Page 1

UK March - April 2012



Room a Grow de ls insi Detai

Everything is Automatic

Forcing the Bloom

High-tech tips and tools for grow room excellence

How to yield heavy, high-quality harvests


Indoor gardenING expo DENVER




March 10 - 11

June 2 - 3

July 21-22







Maximum Yield UK | March / April 2012

CONTENTS March/April 2012




Pint-sized Entrepreneurs


Strong Stems, Healthy Plants


Planning a Garden for Spring


Controlling Salt Buildup


by Heather Pearl


Boosting the Bloom


Killer - All-natural Neem Oil


The Pythium Predator

by Brian Chiang and Josh Puckett by Lee McCall

by Dr. Lynette Morgan


From the Editor


You Tell Us



Do You Know?

by Donald Lester


Letters to the Editor


Industry’s Latest

Troubleshooting Your pH Tester


Simon Says


Max Mart


MAX Facts


Coming up in May/June


Product Spotlight



by Robbie Martin

Use Less Water (and Grow More) by Dr. J. Benton Jones, Jr.


Cloning Wars: Part Two

by Matt LeBannister

by Beth Dumey and Steve Goldberg



How to Grow a Bonsai From Tree Seeds by Marc Alexander

Maximum Yield UK | March / April 2012


FROM THE EDITOR | Jessica Raymond

Make this the month you try something new! Test out the latest LED lighting options; try all-natural neem oil to kill grow room pests; discover the beauty of bonsais grown indoors. Why not? We’ve pumped this issue full of grow tips, information, education, challenges and treats. Want to learn about the latest new products? This issue contains a comprehensive round-up of the newest products available to help you grow. Check them out at your favourite grow shop. And make sure to enter for a chance to win some of these products in our ‘Win A Grow Room’ contest. Enter online today at This month we kick off our 2012 ‘Grow Like A Pro’ Indoor Gardening Expo Tour in Denver. You’re invited to attend March 11 to learn from the experts, preview the latest products and technologies, and catch up with old and new friends. If you’re unable to visit Denver, you need not worry as we have world-class events lined up in Novi, Michigan; San Francisco, California; and Long Beach, California. Check out and make plans now to visit one of our expos.

Jessica Raymond, Editor

contributors Dr. Lynette Morgan holds a B. Hort.

Steven Goldberg is marketing

Tech. degree and a PhD in hydroponic greenhouse production from Massey University, New Zealand. Lynette is a partner with SUNTEC International Hydroponic Consultants and has authored five hydroponic technical books. Visit consultants.htm and www.suntec. for more information.

manager for Oakton Instruments and has more than 21 years experience both in the laboratory and marketing as well as developing laboratory instrumentation including pH meters.

Heather Pearl is completing her

Brian Chiang has worked for

Donald Lester is the plant

Lee McCall is an alumnus of Johnson &

Josh Puckett earned his bachelor’s

Matt LeBannister developed a

Robbie Martin works for Vital

DiCon Fiberoptics, Inc., an advanced technology company based in California, for the last 13 years. Brian received his bachelor’s degree in physics from UC Berkeley and master’s degree in physics from UC Davis. He is currently the managing director for Kessil Lighting, a DiCon business division.

degree in biology with an emphasis on plant biology from Sonoma State University. He currently works at the UC Davis Foundation Plant Services. He has years of experience in the horticulture and agriculture industries. He also serves as an advisor for the Kessil Research team.

Beth Dumey is senior marketing communications specialist for Oakton Instruments. As a professional communicator, her articles have appeared in a variety of trade magazines, newsletters, and online venues. Visit


Maximum Yield UK | March / April 2012

products manager at JH Biotech, Inc., a California based agricultural technology company with 27 OMRI certified products. Donald has a master’s degree in agronomy with an emphasis in entomology. He is an agricultural scientist with over 10 years of research experience and 50 scientific publications to his credit.

green thumb as a child, having been born into a family of experienced gardeners. During his career, he has managed a hydroponic retail store and represented leading companies at the Indoor Gardening Expos. Matt has been writing articles for Maximum Yield since 2007. His articles are published around the world.

Dr. J. Benton Jones Jr. has 50

years of experience growing plants hydroponically. He is an Emeritus Professor at the University of Georgia, Athens and has authored eight books and written articles for magazines that deal with hydroponic issues. He currently has his own consulting company, Grosystems, Inc. Dr. Jones currently lives in Anderson, SC, USA.

BA in development geography at Kings College. She acts as fundraiser for the Little Growers team, helping to increase its exposure and endorsements. She is keen to champion the Little Grower’s cause for worldwide youth education in the fields of health and horticulture.

Wales University. His extensive culinary background helped him gain experience in and knowledge of fine dining and food production, which developed into a career in the hydroponics and year-round gardening industry. Lee and his business partner use their Denver-based businesses to educate the public on sustainable gardening and high quality produce.

Landscaping Inc. in the sierra foothills town of Grass Valley, California. He holds an associate of science degree in horticulture and nursery crop production from Cabrillo College and attended a two year apprenticeship in ecological horticulture at the University of California Santa Cruz.

Become a Maximum Yield contributor and have your articles read by 250,000 readers throughout USA, Canada, UK, New Zealand and Australia. Maximum Yield is the largest free-to-consumer indoor gardening magazine in the world. Every issue is available on, which has thousands of unique visitors monthly.

Maximum Yield UK | March / April 2012


Coming up on the Web Upcoming Events

‘Grow Like A Pro’ in Denver, Colorado, March 11, 2012 Maximum Yield will be returning to Denver, Colorado March 11 to kick off the 2012 Indoor Gardening Expo ‘Grow Like a Pro’ Tour. Take a vacation in this vibrant city; Maximum Yield and the Colorado Convention Center welcome growers from around the world to participate in a full day of networking, education and entertainment. Visit for complete event details.

Free Digital Subscription to MaximumYield Now you can receive Maximum Yield UK free to your inbox every month. Subscribe to the digital edition of Maximum Yield by simply filling out the form at

Got Questions? Get Answers.

VOLUME 11 – NUMBER 6 March/April 2012 Maximum Yield is published bi-monthly by Maximum Yield Publications Inc. 2339A Delinea Place, Nanaimo, BC V9T 5L9 Phone: 250.729.2677; Fax 250.729.2687 No part of this magazine may be reproduced without permission from the publisher. If undeliverable please return to the address above. The views expressed by columnists are a personal opinion and do not necessarily reflect those of Maximum Yield or the Editor. Publication Agreement Number 40739092

PRESIDENT/PUBLISHER - Jim Jesson GENERAL MANAGER - Don Moores BUSINESS MANAGER - Linda Jesson EDITOR - Jessica Raymond ADVERTISING SALES 250.729.2677 Linda Jesson - Lisa Lambersek - Ilona Hawser - Hayley Jesson- Ashley Heppell - PRODUCTION & DESIGN Alice Joe - Jenn Duong - Liz Johnston - Denise Higginson - ACCOUNTING Tracy Greeno - Tara Campbell -

Maximum Yield’s resident experts are available and ready to answer your modern gardening questions. E-mail or fill out the Ask the Experts question form on

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Maximum Yield UK | March / April 2012

UK DISTRIBUTION Growth Technology Future Harvest Developments Europe Nutriculture UK Direct Garden Supplies Dutchpro Maxigrow Ltd. CANADIAN DISTRIBUTION Brite-Lite Group Biofloral Eddis Wholesale Greenstar Plant Products Inc. Hydrotek MegaWatt Northern Hydroponic Wholesale Quality Wholesale USA DISTRIBUTION Aurora Innovations BWGS General Hydroponics Humboldt Wholesale Hydrofarm Hydro International National Garden Wholesale / Sunlight Supply Nickel City Wholesale Garden Supply R & M Supply Tradewinds AUSTRALIAN DISTRIBUTION Dome Garden Supply Futchatec Growth Technology Holland Forge House N Garden Hydraspher

Maximum Yield UK | March / April 2012



Just checking out the latest issue of MY and it looks great. Love the articles and the graphics. There’s a lot of good stuff in here, a lot of helpful information. My favourite articles from this issue are from my favourite writers including Grubbycup, Dr. Lynette Morgan and Casey Jones Fraser. Keep up the great work. Maximum Yield rocks! Josh Simmons

Lovin’ it

We absolutely love your publication! Thank you for bringing such amazing articles to our industry. Natalie Elola

A Question of Safety

I was happy to find your site and all the great and helpful information you offer. I know absolutely nothing about hydroponics but am very interested in learning. Like any new field, there seems to be endless choices of ways of getting started in growing. I’m not looking to go commercial with it—just to provide for my family and friends. I want to grow organically, and am not clear if this is possible hydroponically. I guess my inquiry is: how can someone like me with zero knowledge about this get started? Do you know of any sites similar to yours that perhaps offer online video tutorials or something like that? Do any full line product suppliers offer something like this? Understandably with our busy schedules it’s difficult to learn these things just searching on our own. Thanks for any suggestions or referrals you can make that would assist me. Jason Trader Jason, you’re in luck. With every issue of Maximum Yield UK, one of our goals is to introduce beginners to modern gardening techniques and tools and help people like you navigate the oftentimes perplexing practice. In the following pages we cover: cloning and LEDs, pest and disease management, gardening planning, plant health and much more. If we failed to answer your questions, I invite you to fill out our Ask the Experts question form at Maximum Yield is here to help you in your hydroponics venture. Good luck and do keep us updated on your progress!

Inspired Reading

I just started receiving my new subscription to Maximum Yield. I absolutely love it—with new growing techniques, nutrient recipes from the experts and tips and tricks for every subject in between. I especially liked Frightful Weather, Delightful Tomatoes by Casey Jones Fraser from the Jan/Feb 2012 issue. Maximum Yield is going to be the vehicle for me to be a better gardener, indoors and out. Aimee Lamson


Maximum Yield UK | March / April 2012

We want to hear from you! Maximum Yield Publications Inc. Snail-mail: 2339 Delinea Place, Nanaimo, BC V9T 5L9 E-mail: Twitter: Facebook:


Hey Simon, It’s my understanding that humic acid is a great source of carbon for plants and that it’s readily absorbed by plant roots. If one is using humic acid in their nutrient stock tank can they cut back on the amount of CO2 injection in the grow room atmosphere? Thanks, Craig

An interesting question Craig, and I can see where you are coming from. The short answer is that humic acid cannot replace carbon dioxide.You are correct in the assessment that humic acid can provide carbon dioxide but it’s in an indirect manner, not directly from this carbon-based substance. Humus is a degraded form of organic material high in carbon; in essence it is fully digested organic material that resists further decay. However, soil microbes can be stimulated by its presence and this activity will release low levels of CO2 as the soil life breathes. Continue adding carbon dioxide to your growing area in the range you are trying to achieve, and don’t adjust for the microbial increase. If you want to, it is possible to measure activity in the soil with specific equipment but in an indoor growing area it is unlikely that microbe activity would provide more than a negligible level of CO2. It is absolutely correct that humic acid is beneficial to plants’ roots (and functions), but also to soil and microbes. Humic acid is an extract derived from ancient deposits of organic matter. In current top soils it exists as humus, and both humus and humic acid are great for plant roots. Humic acid has an extremely high cation exchange capacity and this alone is of great benefit. In its simplest terms humic


Maximum Yield UK | March / April 2012

acid gathers a variety of nutrients and then shuttles them into the plant very efficiently. On top of this, new research suggests that if the substance moves through the root system and into the plant it has similar effects to some plant hormones. Although the mechanism still eludes us, this is a very interesting development in understanding this complex substance. The biodiversity in the rhizosphere expands more rapidly in its presence, which provides vast indirect benefits due to microbial secretions such as growth regulating substance, organic acids, disease suppressing compounds and unique carbohydrates such as glomalin. On a related point, if you are trying to create an aerobic compost tea for disease prevention, new research suggests you should be taking out the molasses and using a blend of humic acid and kelp as the catalyst for bioactivity. When choosing a humic acid there are many options but for those of you running a true water system I would choose a low molecular weight humic fraction product generally referred to as fulvic acid. For more information be sure to check in at your local shop to review the variety of brands and extraction methods available.

Do you have a question for one of our resident experts? Send it to or fill out the form on and your answer might be printed in an upcoming issue.

Maximum Yield UK | March / April 2012



hydroponic news, tips and trivia

Seeds Need Elephants Habitat fragmentation and climate change are threatening seed dispersal patterns in most human-modified landscapes around the world, according to a study published in the journal Biological Conservation. An ecologist at the Centre for Ecological Science at the Indian Institute of Science said, “…there is…a growing crisis around the world when it comes to seed dispersal, yet it is not fully recognised or understood.” According to the study, one of the main contributing factors in the disruption of established seed dispersal patterns is that “many of the largebodied animals that transport seeds, such as elephants, are [now] extremely rare or absent from the non-forest [landscape].” (Source:

MAXFACTS hydroponic news, tips and trivia

British Seed Companies Unveil New Varieties British seed companies have been unveiling their latest discoveries for spring and some of their new finds are spectacular—including a pumpkin that tastes like a butternut squash, red and green lettuce and blight-resistant potatoes. Developing viable new strains of produce that appeal to home gardeners is not always a priority with commercial seed companies, though, according to Martin Harvey, managing director of Marshalls Seeds: “The factors we [as gardeners] consider important are at odds with those of commercial growers, where very short harvest intervals, high yields and uniformity are all-important. This very fact means that we and our competitors find it increasingly difficult to find varieties that are ideal for the home gardener.” (Source:

Allotment Thieves Nabbed in Veggie Lineup Police in Brampton, Cambridgeshire recently caught a brazen gang of thieves after holding an unusual identity parade—of stolen vegetables. Two offenders were ordered to pay £20 in compensation and £85 in costs at Huntingdon Magistrates’ Court after allotment holders identified their purloined produce in a roadside lineup. The two convicted were caught red-handed with a bag of stolen vegetables by local police. (Source: 14

Maximum Yield UK | March / April 2012

Maximum Yield UK | March / April 2012



hydroponic news, tips and trivia

France Loses its Wildflowers A recent study by the Wildlife Department of the French Environment Ministry has concluded that French wildflowers are disappearing at a rapid rate and that pesticides associated with industrial farming practices are to blame. “All over Europe the situation is the same, with these species in serious decline,” a spokesperson said, adding that since the advent of modern farming techniques species like pheasant’s eye, cornflower, corncockle and Venus’s looking glass have “been treated as weeds.” (Source:

High-tech Supermarket Farm Planned for Netherlands Dutch company Van Bergen Kolpa Architecten hopes to produce a working prototype of a ‘supermarket farm’—a new model for urban food production that could grow practically any food customers demand—within the next year. The 4,000 acre farm, which will be divided into production areas for every type of produce, grains, meats and other products, will be capable of growing kiwis even in the cool, gray climate of northern Europe. (Source:

Seasonal Blooms Enliven Living Roofs in Korea Superstar architect Joel Sanders has partnered with Haeahn Architecture to create a series of 12 staggered Seongbukdong residences with living roofs—planted with a variety of sedum species—that bloom at different times of the year. The living roofs insulate the buildings and erupt into riots of colour with the changing seasons. (Source:


Maximum Yield UK | March / April 2012



HOTTEST ITEMS Ask for them at your local indoor gardening store.

Award-winning Original Grow and Bloom Hydro/Coco A+B for Soft Water Dutchpro’s original award-winning grow and bloom hydro/coco A+B for soft water have all the essential macro-and micronutrients necessary for exuberant growth. For use as a feritiliser, use 250 to 350 millilitres per 100 litres of water. Never mix components in pure form with each other—instead, add component A, water and then component B in equal parts. Adjust pH level if necessary. Both the grow and bloom formulas are available in one-litre, five-litres, 10-litres and 20-litres. Ask for the original grow and bloom hydro/coco A+B for soft water from Dutchpro at your favourite hydroponic shop today.

Maxibright DigiLight 150 Watt Digital HID Power Pack The Maxibright DigiLight 150 watt digital power pack has a lightweight design (only 1.5 kilograms), runs silent and has proven reliability. Features: soft start technology for longer lamp life; RF shielded; flying lead IEC connection; runs both sodium and metal halide lamps; low startup current; and thermal protection with auto reset. The Maxibright DigiLight also available in 250, 400 and 600 watts. The Maxibright DigiLight offers greater lumen power per watt than other lighting systems. Compared to CFLs, fluorescents and LEDs, HID is still the most efficient light source available. Check out the Maxibright DigiLight at your local indoor gardening shop.

Dutchpro Seeds—Vegetables, Fruits, Herbs and Flowers The entire Dutchpro seed collection includes 30 varieties of carefully selected and tested vegetable, fruit, herb and flower seeds to guarantee the best quality. We offer the following strains: Vegetable and fruit strains: beetroots, carrots, garden cress, round lettuce, tomatoes, rad-ishes, chillies and strawberries Herb strains: basil, chive, mint, parsley, winter thyme, majoram and rucola Flower strains: alyssum, aster, cornflower, godetia, impatiens, lobelia, sweet pea, nasturtium, petunia, salvia and sunflower For more information visit your local indoor gardening shop. And while you’re there make sure to check out the entire Dutchpro range of products.


Maximum Yield UK | March / April 2012

Maximum Yield UK | March / April 2012



Universal B’cuzz Boosters Now Available in 100 millilitres As always, Atami remains responsive to consumer needs. In September, 2011 Atami released the one and five litre bottles of B’cuzz Universal Boosters. Now, to satisfy hobby growers, they’ve added a 100 millilitre bottle to the range. B’cuzz Boosters are completely soluble in water and will greatly enhance the root growth of your plant. Because the boosters contain chelated micronutrients, the plant only absorbs what it needs, leading to less waste. B’cuzz Universal Boosters also contain all the components necessary for the plant’s citric acid cycle. If used correctly you can expect bigger roots, bigger leaves and great vitality from the plant. The B’cuzz Booster 100 millilitre bottle will be available at your local retail shop soon.

Low Rider™ Air-Cooled Reflector (six inches) Announcing the arrival of Low Rider™, the newest air-cooled reflector in the Sun System Reflector lineup. The Low Rider™ has the distinction of being the most compact high output hood on the market! It is unique because it’s only 15 centimetres tall (44 by 44 centimetres square) for low ceilings or use between floor joists. It’s completely sealed with hinged and double gasketed glass, and features 95 per cent reflective European aluminum interior and built-in six-inch oval shaped air-cooled flanges with bead ring to keep ducting securely in place. Visit an indoor gardening shop near you for more information.

AQUAbox Straight The AutoPot AQUAbox Straight incorporates the AQUAvalve technology but is designed to be placed directly in the ground. It is ideal for large planters, narrow raised beds, grow bags and allotments. Simply place the AQUAbox Straight in the ground and connect to a waterbutt or tank. The capillary matting pulls the water from the AQUAbox Straight and distributes it into the soil below. The roots instinctively head to the water source and attach to the capillary matting. You can connect several AQUAbox Straights to one waterbutt or tank to irrigate a larger area. The AQUAbox is the perfect irrigation solution for weekends or holidays away and year-round watering. No electricity or pumps required. Visit for more information.

Cyclone ONA Fan - High Efficiency Airflow Design a Win-Win for Odor Control Odorchem Manufacturing Corp., the makers of ONA Odour Neutralizers, is pleased to introduce our new ONA Cyclone Fan. Unlike its predecessor, the ONA Storm Fan, our new high-efficiency airflow design draws air in a cyclonic motion from above the fan propelling it directly into the pail of gel providing a 30 per cent increase of ONA into the air. ONA Cyclone provides enough air circulation to neutralize odours in a room up to a maximum of 5,000 square metres. Check out the Cyclone ONA Fan at your local indoor gardening shop.


Maximum Yield UK | March / April 2012

AutoPot Easy2grow Liquid Feed The AutoPot easy2grow Liquid Feed has been specially formulated to be used with AutoPot products, however, it is suitable for use in all watering systems. During recent trials it outperformed all the rest and is perfect for use with all kinds of plants. It is now available in a range of sizes including: 250-milliliters, one-litre, five-litres and 20-liters. Easy2grow Liquid Plant Fertilizer will leave minimal sediment ensuring clear lines and piping, and the optimum performance of the AutoPot irrigation system. It is a one-part feed that dilutes extremely well in water, so will remain mixed. It provides all the required nutrients with added seaweed to ensure you crops will bloom and grow to their full capacity time and time again. Visit an indoor gardening store near you to check it out.

Maxibright DigiLight Pro Variable 400W/600W HID Power Pack The Maxibright DigiLight Pro is a lightweight, selectable output digital power pack. With four power modes, you can use either sodium or metal halide lamps for each mode. Equipped with end-of-life detection and shut-off circuit, plus rubber mounting feet. This product has proven reliability: • Four power modes • Two super lumen modes • Soft start technology for longer lamp life • Silent operation • RF shielded • Flying IEC connection • Runs both sodium and metal halide lamps • Low startup current Check out the Maxibright DigiLight Pro Variable at your local indoor gardening shop.

Maximizer Reflector® Sunlight Supply®, Inc. is pleased to announce the return of the Maximizer Reflector®, the newest reflector in the Sun System Reflector lineup. This economical reflector is made with the same 95 per cent reflective German aluminium that we use in all of our Sun System® reflectors. The adjustable beam spread design allows for specific light distribution depending on your garden size and shape. It is lightweight and simple to use. It is pre-wired with a cord and mogul socket. Visit an indoor gardening shop for more information.

Maximum Yield UK | March / April 2012



Titan Controls® Flo-N-Brew™ Titan Controls® brings you the perfect solution for your compost tea brewing requirements— the Flo-N-Brew™. This tea brewer features Xtreme Gardening Xtreme Tea Brew. This compact and easy-to-use compost tea brewer comes with everything you need to brew two 11-litre batches of premium compost tea for your garden—all you have to add is water. It comes with an 11-litre tea brewer, air pump with hose, Eco 185 submersible pump, fountain kit and two air stones. Titan Controls® - bringing you quality environmental controls and garden systems. Gardening with the gods—what could be better? Visit your favourite gardening shop for more information.

Measure Me Digital Measuring Cup Quickly and easily measure both solids and liquids with just one cup. The Measure Me 600 millilitre digital measuring cup features a scale built into the bottom of the handle to quickly and accurately measure weight and volume. Choose from pounds, carats, cups, ounces, millilitres or grams with a maximum capacity of 600 millilitres or 2.2 pounds. Measure Me features a detachable handle for easy cleaning and measures the ambient temperature in Fahrenheit or Celsius. This cup can also measure multiple ingredients at one time using the TARE feature, has a pre-set weight function and a 30 minute timer, and a blue backlit display screen. Ask your favourite garden retailer to carry Measure Me today.


Maximum Yield UK | March / April 2012

Original Grow and Bloom Soil A+B for Soft Water Dutchpro’s original soft water grow and bloom feed formulas purposely designed for use in soil has all the essential macro- and micronutrients necessary for exuberant growth and bloom. For use as a feritiliser, use 200 to 300 millilitres per 100 litres of water. Never mix components in pure form with each other—instead, add component A, water and then component B in equal parts. Adjust pH level if necessary. Both the grow and bloom formulas are available in one-litre, five-litres, 10-litres and 20-litres. Ask for the original grow and bloom soil A+B for soft water from Dutchpro at your favourite hydroponic shop today.

Introducing Botanicare's New Redesigned Power Cloner Line Botanicare® Power Cloners™ have been modified and improved. Redeveloped with Botanicare’s low profile reservoir, these systems decrease propagation time and now include an array of new features and benefits: • • • • •

• • •

Unique Botanicare Cord Guide designed to block sprayed solution and improve cord management Drainage grid with a recessed pump An internally seated tray Humidome™ options* Customizable points for installation of spouts and fittings Botanicare Ceramic Airstones with Air Pump Water volume indicator Dense neoprenes

These highly affordable second generation Power Cloners™—45, 77 and 180—are now available in black* (100 per cent recycled ABS plastic) and white (70 per cent recycled ABS). *Black Power Cloners do not include a Humidome. The Humidome can be purchased separately. Visit your favourite hydroponics shop for more information.

Introducing Maxibright Maxiswitch Pro Control Units Assembled in the UK, Maxibright Maxiswitch pro control units are built to strict CE standards using only the highest quality components, including Grässlin timers, GE contactors and IMO relays. For safe switching of HID lighting, the Maxiswitch Pro 2 uses a heavy IMO relay. The range offers unrivalled quality and reliability: • Heavy duty cables and wires • Easy to operate Grässlin panel mount timer with 15 minute segments • Hardwearing, rubberised moulded BSI approved plugs designed to be break-proof • IMO relay for dependable switching (Pro 2) • Two year guarantee for peace of mind Total maximum switching capacity: must not exceed 13 amps on Pro 2 and 26 amps on Pro 4, 6 & 8. Visit an indoor gardening shop near you for more information.

Introducing Farmer Friendly Mykos The most awarded name in Mycorrhizae just added a farmer friendly size to the mix. MYKOS, used by the top growers across the United States and abroad for creating faster-growing, higher-yielding plants, is now available in 50 pound farmer sacks. If your garden demands the best beneficial biologicals, get it in a commercial size and price that makes it a cost-effectiveww addition for any gardener’s budget. Visit an indoor gardening shop near you for more information.

AutoPot Introduces the AirDome The AirDome is the perfect accessory for gardeners of all abilities, designed to increase the amount of air around the root zone in potted plants. The AirDome can increase yields by up to 130 per cent. It is very simple to use once assembled, which will take less than 30 seconds. The AirDome is placed at the bottom of the pot, covered with medium and then connected to an air pump. Oxygen is then supplied directly to the plant’s root zone. To maximize the effectiveness of the AirDome use a fluffy mix, such as 50 per cent good quality compost or coco and 50 per cent perlite. The AirDome is ideal for use with AutoPot Watering Systems. Visit an indoor gardening shop near you for more information.

Maximum Yield UK | March / April 2012


O W T T R A P ckett d Josh Pu

S R A W G N I N O CL h by Brian C

iang an

t o o R s e k Ta y g o l o n h ec T D E L x i r t Dense Ma

As the use of dense matrix LED technology becomes more prevalent in the horticulture industry, indoor gardeners are finding ways to expand beyond traditional growing applications. The innate ability of LEDs to emit specific wavelengths has proven invaluable when applied during the normal growth cycle of plants. As researchers discover more about the effect of light for various crops during different stages of development, they will continue to rely on LEDs to create and test these spectrums.


Maximum Yield UK | March / April 2012

The advent of dense matrix LED technology, which compacts many LED chips into a single point source, offers more than long lifetimes and energy savings. This platform is able to unite multiple wavelengths to produce one uniform spectrum that not only eliminates sporadic hot spots, but also allows the entire spectrum to penetrate deeply into plants. This capacity is intriguing to both indoor growers and researchers alike, as dense matrix LED products can now be used in more applications than just during the vegetative or flowering phases of growth.

Rethinking Light Spectrum and Plants

A significant percentage of how plants perceive their environment and the passing of time is through the reception of light. Throughout their evolution, plants have developed pigments and photo-sensory complexes that allow them to detect the quality and quantity of light they are receiving. These biological mechanisms often trigger hormonal responses that communicate to parts of the plant whether they should do things like grow longer, initiate flowering or generate roots Most growers are familiar with plant groupings that include categories like ‘sun loving’ and ‘shade loving.’ These terms describe plants by their light intensity requirements—or the quantity of light they need to flourish. With the advancement of LEDs, we’re beginning to see a shift toward describing plants by their spectral requirements, which, like light intensity requirements, vary among plant species and varieties. Spectral information not only includes ideal wavelengths, but also the quality of light needed. Individual plants require different spectra and intensities throughout their life cycle. Although it is currently difficult to make broad assertions on spectral requirements, we are researching plant reactions to light spectra and intensity amongst different species. The versatility of LEDs to define light spectra makes this technology the perfect medium to

find optimal wavelength combinations for different plants throughout their growth cycles We’ve seen positive results from vegetative and reproductive tests using dense matrix LED grow lights, and our research has developed from this success to include experiments on plant steering, cloning and more. Last issue we described the initial results of wavelength testing on root formation from propagated cuttings, or clones, and through the use of dense matrix LEDs we were successful in promoting roots, although it was unclear which spectrum actually proved most effective. We continued our rigorous testing and experimentation using herbaceous and dormant hardwood cuttings of different plant species and subjecting them to various wavelengths of LED light.

Initial Experiments: Husky Red Cherry Tomatoes

As a recap of our initial experiments, we previously cloned Husky Red Cherry Tomatoes using green cuttings without hormones. Our results are based on observing the days until callus formation, root formation and root branching occurred among the cuttings. At the end of each experiment, percentages of these parameters were taken, in addition to wet and dry weights of generated root mass. To determine whether the presence of light played a role in hastening rooting or increasing the amount of produced root mass, tests were done comparing groups subjected to high-intensity light and complete darkness. Tests were repeated numerous times to confirm results, each time confirming that green tomato cuttings root faster and produce more root mass when light is present. Next, we compared the role of light intensity upon rooting in herbaceous cuttings.

Maximum Yield UK | March / April 2012


Cloning Wars Part two: Dense Matrix LED Technology Takes Root

Secondary Experiments: Marianna Plum Rootstock and Dr. Huey Rose Rootstock We rooted 15 terminal and

Different clones from the same parent tomato plant

axillary propagations in cloning units subjected to different intensities of light. The number of dense matrix LED grow light units that were suspended above the cuttings controlled the difference in intensity. From these tests we confirmed that green tomato cuttings do not require high intensity light to generate sufficient root mass quickly. There was little difference in quickness of rooting and biomass production among the groups. Having observed that light intensity, except in cases of extreme excess or deficiency, does not critically affect the rate and amount of root production, we next focused our efforts on identifying wavelengths and spectra that do. We rooted 15 terminal propagations in cloning units under different wavelengths of light and observed the differences in rooting. Original trials tested green, blue, red and purple

(a mixture of red and blue wavelengths) dense matrix LED units as root-promoting light treatments. To eliminate the possibility of data corruption due to differences in cloning units, we repeated these tests multiple times. Cloning units were thoroughly cleaned, and unit components were switched before each trial. We maintained uniformity by matching each cutting’s stem length, stem width, leaf number and number of nodes to eliminate possible bias from cutting size and origin on the mother plant. Most of our trials demonstrated red to be the best light treatment for producing the most root mass in the herbaceous tomato cuttings. We recorded the longest roots with the highest percentage of branching in cuttings under the red LED treatment. Both wet and dry weights of root mass were the highest in this group at two weeks after the cuttings were stuck, and outside comparative tests done by industry representatives confirmed these results.

To verify our initial observations, we ran secondary tests, analyzing how isolated wavelengths and wavelength mixtures

affect root development in propagated cuttings. While herbaceous tomato cuttings produced the most root mass under the red LED light, we wanted to analyze whether this was also true for different plant species. Our secondary tests also used dormant or hardwood cuttings instead of herbaceous cuttings. Since dormant cuttings take longer to root, performance differences under each wavelength should be accentuated. It is also easier to maintain uniformity in the rooting plant material with dormant cuttings.

Dr. Huey Rose Rootstock

Husky Red Cherry Tomato cuttings subjected to darkness


Maximum Yield UK | March / April 2012

Husky Red Cherry Tomato cuttings subjected to high intensity light

Using the same cloning units, we rooted 15 dormant 23 centimetres Dr. Huey Rose rootstock cuttings under red, purple and blue LED

Photographs of foliage and roots of Husky Red Cherry tomato green cuttings subjected to red, purple and blue LED light treatments

Photographs of foliage and roots of Dr. Huey Rose Rootstock dormant cuttings subjected to red, purple and blue LED light treatments

light. As before, we recorded days until callus formation, root formation and root branching among the cuttings. We also recorded the days until bud break, and compared vegetative production with root production. At the end of the experiment percentages of these parameters were also taken, in addition to wet and dry weights of generated root mass. As before, we observed the most significant root production in those cuttings subjected to the red LED treatment, and these cuttings produced

the longest roots with the highest percentage of root branching. What was interesting to note in this experiment was the difference between callus and root formation among the treatments. The cuttings under purple and blue LED light produced considerably more callus, while the cuttings under red LED light produced significantly more roots. In addition, there was noticeably more bud break and vegetative growth of the cuttings Maximum Yield UK | March / April 2012


Cloning Wars Part two: Dense Matrix LED Technology Takes Root

The cuttings under purple and blue LED light produced considerably more callus, while the cuttings under red LED light produced significantly more roots.”

under the purple and blue treatments than there was in those under the red treatment. Further research will be required to investigate the significance of any correlation between these observations.

Marianna Plum Rootstock

We approached the Marianna rootstock cuttings using a different cloning method. We filled a five by eight centimetre ebb

and flow tray with perlite, and stuck the 15 centimetre cuttings into the tray. Suspended above the cuttings were red and blue LED units, and the tray was on a timer set to flood twice daily for five minutes each time. Through this experiment we confirmed that our observations in the previous trials were not the result of variation in the cloning units. As before, we observed increased production of root mass in those cuttings rooted under the red LED. The percentage of root branching was also higher among those cuttings under the red LED treatment. While we did record increased rooting percentage in the cuttings under the blue LED treatment, the amount of roots produced was inferior to those rooted under red LED light. Trials of this experiment are currently being repeated


Rooted Marianna Plum Rootstock cuttings


Maximum Yield UK | March / April 2012

Though we are continuing our research, our current results indicate a correlation between root mass production and red light among propagated herbaceous and dormant cuttings across a variety of plant specifics. Red light seems to promote root elongation as well as root branching in cuttings despite different methods of rooting. The flexibility of LEDs to produce specific wavelengths—and the advancement of dense matrix LED technology, that compacts these

wavelengths to create spectrums—is revolutionizing the indoor growing industry. By providing spectral variation, growers can choose the best spectrum for various species and different phases of growth. The capacity of dense matrix LEDs to emit these spectrums is also increasing our knowledge of plant light requirements by giving researchers the tools to investigate wavelengthdriven plant responses. With this new understanding, and as LEDs continue to expand lighting applications, we will eventually be able to fully transform how we garden indoors. MY

Marianna Plum Rootstock rooting experiment set-up

Initial Husky Cherry Tomato rooting experiment set-up

Maximum Yield UK | March / April 2012


Boosting the

Bloom by Lee McCall


his article demonstrates how vigorous rooted cuttings can transition, stress-free, into flowering. The end result, if carried out correctly, should be strong insect- and disease-free plants that possess healthy, dense foliage and plenty of potential fruit sites, and that will eventually yield heavy, copious harvests of high-quality, prime-grade produce.

Transition The initial transition from vegetative growth into flowering may induce stress on certain varietals and hybrids. Grow room factors such as ventilation, carbon dioxide


Maximum Yield UK  |  March / April 2012

enrichment and lighting might influence various growth patterns as well. Flowering is often autonomous in many different crops, though, and these types might not shock from light deprivation, transplanting or switching base nutrients from grow formulas to those intended for flowering/fruiting/blooming. Initial root health is always a major contributing factor to the final product. Ensuring there is plenty of room for root expansion once a plant is induced into the flowering phase is imperative for allowing it to grow and mature, as bigger roots are needed to support the mass quantities of blooms and foliage that are produced during crop flowering cycles.

If root growth is restricted, growth is stunted and yield could ultimately suffer. Growers using container gardening techniques with soil, coco or soilless mixes might benefit from conducting the initial (seedling or cutting) vegetative growth cycle in smaller volume containers (two to four litres), and later upgrading to larger ones as needed for mature (three to eight week+) plants that become root bound. Once a plant is root or pot bound, overall growth is slowed dramatically. A variety of aeration containers are available in both fabric and injection-moulded types to prevent root circling, the main cause of root binding. These containers promote feeder root growth through root pruning, a technique that uses air to singe off root tips as they pierce through the fabric walls or into open pockets in the injec-

“Depending on the style of system and method implemented, transplanting may... be completely nnecessary.”

Maximum Yield UK | March / April 2012


boosting the bloom

tion moulded containers. As the root tips die off from the air, the resulting effect is dramatic feeder root stimulation. This technique is similar to topping and cropping plants in order to achieve more tops and fruiting sites. Transplanting can be performed the same day that the crop is induced into flowering, or delayed so that the plant has time to adjust and settle into its new home prior to beginning the bloom phase. Hydroponic growers making effective use of grow blocks, hydroton, silica rock or PET-1 as their choice of grow medium can achieve much larger plants and yields with much less grow medium in comparison to soil or soilless grow substrates. Depending on the style of system and method implemented, transplanting might also be completely unnecessary. For example, many DWC (deep water culture) and aeroponic systems are engineered to harbour small and large (two+ metres) plants without having to transplant at all, due to self-contained reservoirs able to hold adequate amounts of nutrient solution over a given period of time. In drip irrigation and the occasional flood and drain system, 10 and 15 centimetre grow blocks will usually accumulate prolific root masses over the course of a two to four week veg cycle. These root bound blocks can be placed on grow slabs, coco coir mats or PET-1 mats in order to allow the roots extra 32

Maximum Yield UK | March / April 2012

room for growth and to provide simultaneous protection from light and direct air. Mesh-bottom containers and net pots full of other grow mediums can also be placed on rooting mats in order to promote the same effect as grow blocks. A mycorrhizal inoculant or a compost tea heavy in beneficial bacteria, nematodes and protozoa should be incorporated in order to promote rapid root growth and healthy diseasefree foliage and to deter transplant shock. Granular forms of Mycorrhizae are recommended for soil, coco and soilless container gardening applications, and powder forms are available for hydroponic systems. Always use a de-chlorinator and a sediment filter on the water source to preserve the activity and concentration of all microbial inoculants and teas. Tap water might not render these living additives completely useless, but the chlorine, chloramines and heavy metals found in municipal water supplies will definitely ensure the possibility that the additive or inoculants being utilized might not perform to their fullest potential. Finally, shower the garden with a high quality seaweed (Ascophyllum nodosum) supplement when inducing the switch from veg into bloom. This luxuriant sea plant has been known to encourage fruit site development and bud sets in many crops—compared to controls without treatment— when first introduced into a flowering regimen. Many plants will triple in size once set into flowering as long as they are given desirable conditions and adequate space for the roots and foliage to grow into.

Bulking with P/Ks In weeks two through eight of the flowering stage it is important to be consistent and ensure that the crop does not fall victim to pest and mildew infestations, nutrient overdoses or deficiencies as their root masses grow. Any one of these important factors—along with others—could be responsi-

ble for the failure of what might have been a bumper crop. Bloom-boosting products that incorporate plenty of L-amino acids and high-to-low ratios of phosphorous and potassium to nitrogen will fuel weight gain and aroma in blooms and stimulate sugar production in leaf tissue. Carbo-loading is always beneficial during heavy fruiting phases. For growers using beneficial inoculants, these simple and complex sugars boost the levels of microbiological activity in the rhizosphere as they act as a food source for the microorganisms. In sterile hydroponic applications, carbohydrates will enhance flesh density of the produce grown and encourage flavonoids, the

“Organic options may be derived from raw materials like sugar cane, fruit extracts, molasses or malt.”

metabolites in plants responsible for colouration that also act as antioxidants. Carbs are found in many different natural and synthetically processed forms. Organic options can be derived from raw materials like sugar cane, fruit extracts, molasses or malt. Synthetically treated—but not necessarily inorganic—products comprised from deoxyribose, lyxose, ribose, xylulose and xylose are some of my favourite products for bulking up produce and adding weight. Super-concentrated synthetic P/K boosting powder additives are also very popular for incorporating into the feeding during the last weeks before harvest. High percentages of phosphorous and potassium such as a 0-50-30 mix will encourage ripening and last minute bulking in flowers, fruits and vegetables. These additives trick the plant by overdosing its system with high amounts of P/K. This encourages early flower set when used in the transition weeks of the flowering stage. Many of these formulas are extremely concentrated, sometimes calling for as little as one teaspoon per 19 litres of nutrient solution. Organic guano-based additives will provide similar effects with lower concentrations of N-P-K, an option that might appeal to those who wish to garden completely free of synthetic additives and chemicals. Maximum Yield UK | March / April 2012


boosting the bloom

In terms of atmospheric conditions, make sure that there is always plenty of fresh air exchange and control over intake and exhaust of the growing space: the ability to control these factors allows the grower complete automation for finetuning crop production. CO2 enrichment is also always beneficial if available. Whether using compressed gas in bottles or propane/natural gas generators, aim for approximately 1,500 PPM around the plants. Even inducing these conditions in the garden just once a day will benefit your crop—CO2 enrichment will generally increase factors such as growth and overall weight by upward of 15 per cent. And although not mandatory to achieve incredible results, the introduction of CO2 never hurt anything if properly set up and utilized.

Conclusion In conjunction with simple routine maintenance—like regularly replacing grow lamps, keeping the grow room clean and above all being consistent—the information found in this article should prove to be a useful reference to increase your ability to execute bumper crop production. Moving forward, always conduct controlled experiments with plenty of documentation so that all influential factors can be recorded to determine any gains or losses from new techniques or products thrown into the mix. The information you record over the years as you learn from your mistakes and figure out what works and what’s a waste of time and money will be your most important tool as a grower. MY


Maximum Yield UK | March / April 2012


All-natural neem oil will kill bad bugs dead

without harming the good guys With today’s push for more organic gardening in the home garden, it can be hard to balance using natural cures for common problems and still getting a good harvest. Some organic pesticides are not as effective as their chemical counterparts, but there is one exception, and that is neem oil. Neem oil not only effectively kill the pests on your plants (without hurting beneficial bugs like bees) but it can also eliminate most fungus problems. If you are wondering what neem is used for and how you can use a neem oil foliar spray in your garden, keep reading.

• • • • •

Root rot Rust Black spot Sooty mould All other kinds of fungi

Is neem oil safe for humans?

A neem oil foliar spray is used in the garden one of two ways— as an insecticide or as a fungicide.

Neem oil is safe for humans and is a common ingredient in things like toothpaste, shampoo and cosmetics. It is found to be safe in smaller amounts for human consumption, and since insecticidal mixtures of neem oil contain only a very dilute amount of the oil, you can eat fruits and vegetables that are treated without any problems. It is commonly used in organic farming.

Neem oil as an insecticide

How to apply neem oil foliar spray

What is neem used for?

Neem oil is an effective insecticide against many insects that can hurt your plants. These include: • Aphids • Mealybugs • Mites • Scale • Japanese beetles • Whiteflies • Any pest that chews or sucks on the plant Neem oil insecticide doesn’t kill bugs that don’t chew on leaves. All beneficial bugs fall into this category, so you can spray your plants with this organic spray without worrying that you’re harming the good guys like bees, butterflies and spiders. Neem oil insecticide is unique in that it does not immediately kill the insects it affects. Instead, for reasons not yet understood by scientists, neem oil insecticide causes a pest to be unable to maintain hydration, which in turn kills it. Some pests are also repelled by neem oil insecticide, which means they stay away from the plant that was sprayed with neem oil.

Neem oil as a fungicide Neem oil is also an effective fungicide. Applying it to plants can kill harmful and unsightly funguses such as: • Powdery mildew

Neem oil is normally applied as a spray to the leaves of the plant. While neem oil is a good insecticide, there are some things to keep in mind when using it. First, some plants can be killed by neem oil, especially if it is applied heavily. Before spraying a whole plant, spray a leaf on the plant and wait 24 hours to see if the leaf has any damage. If there is no damage, then the plant will not be harmed by the neem oil. Second, neem oil should not be applied to a plant in direct sun. If the plant you want to treat is in full sun, apply the neem oil foliar spray in the evening so that it has time to absorb overnight. Also, do not use neem oil in extreme temperatures, either very hot or very cold. Do not apply neem oil to plants that are stressed, either due to drought or overwatering. Apply your neem oil insecticide about once a week to kill and control pests. Apply neem oil like you would other oil-based sprays—make sure the leaves of the plant are coated, especially where the pest problem is the worst.

Where to buy neem oil

Nurseries, garden centres and hydroponic shops sell neem oil. MY For more gardening tips and tricks visit or check out

Maximum Yield UK  |  March / April 2012


by Dr. Lynette Morgan

Emerging research reveals simple, modern solutions to help even beginner gardeners fight back against Pythium so your plants feel better fast.

38 38

Maximum Yield Yield UK | March/ UK | March/ April April 2012 2012 Maximum

Seedlings are particularly prone to Pythium infection. Here the plant is trying to regenerate healthy white roots after a mild infection.

Pythium. The word strikes fear into many a hydroponic gardener—even those who have never encountered a plague of this nature have usually heard what a scourge this pathogen can be. Unfortunately Pythium can strike at any time and many a new grower has been disillusioned by an outbreak of wilting leaves and browned roots. Pythium is the genetic name for over 50 species in the class Oomycetes, of which only a few are common on hydroponic crops. Pythium ultimum, Pythium aphanidermantum and Pythium dissotocum are the main culprits we encounter in soilless systems, although the range of species being found to cause highly damaging attacks has been growing. In hydroponic spinach, for example, there is one species of Pythium that attacks under cool conditions and another that thrives at higher temperatures.

Pythium spread and infection Pythium is termed a water mould, as it thrives under wet conditions and produces zoospores, which spread by water and through nutrient solutions. In most hydroponic systems there are few natural enemies of Pythium, so once it starts multiplying a large source of inoculum can rapidly develop. The spread of Pythium is relatively simple. After infection, the pathogen produces two kinds of spores—the oospores, which have a thick wall and can survive dry conditions for months or years, germinating again when conditions are favourable for infection, and the zoospores. Released from diseased tissue, these have a pair of beating flagella by which the zoospores swim toward a new plant surface, attracted by chemicals released by plant roots. Once the zoospores have made it to a new site they encyst and infect the plant to start the cycle again. Infection rates with Pythium zoospores are much higher in hydroponic systems with low levels of oxygen in the root zone, which is why overwatering, which reduces the air-filled porosity of a growing substrate, is often a major contributing factor to a Pythium outbreak. One of the main problems with Pythium infection is that while it can rapidly cause symptoms such as damping off on Maximum Yield UK | March/ April 2012


The Pythium Predator

young seedlings, older plants might be heavily infected for some time before any signs are seen, and often the rate at which symptoms appear is dependent on temperature. At higher temperatures, more rapid browning and die-back of Pythiuminfected roots is common, while at lower temperatures many crops don’t show any of the usual symptoms while the pathogen is busy breeding and building up levels of inoculum in the root zone. Many growers are often not even aware they have Pythium, as it can attack the tiny feeder roots without any obvious signs until the leaves suddenly start a midday wilt pattern, by which time there is little chance of control and recovery. Typical symptoms of Pythium infection are die-back of recently germinated seedlings, browning of root tips, loss of feeder roots and the gradual spread of brown, rotten root tissue. The tops of the plants may remain green, but can become wilted during the warmer part of the day. Plant stunting, lack of growth and eventual death usually occur rapidly with severe infections. Milder outbreaks might cause continual, moderate loss of feeder roots, with the plant continually trying to replace these. Short, stubby, thickened roots may also be seen, and overall growth is often severely reduced. Some plants—such as cucumbers in solution culture—are more prone to Pythium attack than others, and this is thought to be due to the large volumes of mucilage produced by the roots, which attracts Pythium zoospores. Mucilage is organic matter or exudate released by healthy root tissue, and it often appears as a whitish mass around and in the root mat. Pythium feeds on organic material such as mucilage, multiplies, then launches a full-blown attack on the root system. Another factor that predisposes indoor or greenhouse hydroponic crops to Pythium outbreaks is the presence of tiny black shore flies or

White, well branched and fully formed, it’s relatively easy to identify a healthy hydroponic root system.

“As with many root diseases, Pythium is extremely difficult to control once it is present at high inoculum rates in a hydroponic system, and prevention is the best form of defense.” fungus gnats, which are attracted to wet growing media and rotting vegetation. Fungus gnat larvae (small white grubs that feed on roots) also ingest Pythium oospores, which then stay in their guts until the insects become flying adults, ready to carry the infection on to a new crop. This is why Pythium, which in itself is much more common under overly damp conditions, is often associated with the presence of fungus gnat flies and larvae.

Pythium control

The first visible sign of Pythium on the tops of plants may be midday wilting and a failure to thrive.


Maximum Yield UK | March/ April 2012

As with many root diseases, Pythium is extremely difficult to control once it is present at high inoculum rates in a hydroponic system, and prevention is the best form of defense. If the water supply is suspected of carrying Pythium spores—which is more common in well or ground water—slow sand filtration or filtrating slowly through 61 to 91 centimetres of granulated rockwool has been found to be effective. The correct dose of UV can also treat a water supply and will reduce the population of swimming zoospores. However, UV can’t be used to treat oospores already in the plant’s root zone or growing media. There has been some evidence that the use of soluble silica at 100 ppm can help control Pythium in cucumbers by strengthening the plant, while many other studies have found that the treatment of nutrient solution with a small dose of non-ionic surfactant (certain types of detergent) can reduce and even eliminate a Pythium outbreak. Much of the current research into control

Spinach is particularly prone to Pythium infection, having two species of Pythium which can attack at high and low temperatures.

of root rot pathogens in hydroponics is focusing on the use of beneficial microbe species, either alone or in combination with effective fungicides and biocontrol agents.

Pythium prevention factors 1. Consider oxygen. A high level of oxygen around the roots is

proven to be suppressive of Pythium and some of the other root rot pathogens as well. Oxygen in most of our hydroponic systems comes from pores in the substrate (the air-filled capacity of the growing media), which holds air. Air has approximately 21 per cent oxygen, while nutrient solution or water can only hold six to 13 ppm depending on temperature. So while aeration of the nutrient can certainly help, especially in solution culture systems, plants can get more oxygen directly from the air. Choosing a highly aerated media—such as a coarser grade of coco fibre with long fibres that open out the substrate, good-quality rockwool or chunky perlite—all mean more oxygenation around the roots, provided of course no one is being too heavy-handed with the irrigation. Forced aeration of the nutrient solution is also beneficial in all hydroponic systems. Creating a good level of turbulence in solution culture systems may also be a valuable technique, because when the flow of nutrient solution is turbulent, Pythium zoospores shed their flagella and encyst, losing the ability to sense and be attracted to infection sites on the roots.

Maximum Yield UK | March/ April 2012


The Pythium Predator

“If the water supply is suspected of carrying Pythium spores—which is more common in well or ground water—slow sand filtration or filtrating slowly through 24 to 36 inches of granulated rockwool has been found to be effective.”

nutrient can keep root temperatures down to an optimal state, but shading the root zone can also be easily carried out. Keeping the air temperature down with evaporative or air conditioning is also an option. Pythium has been proven to be far more aggressive when conditions are hot, and less oxygen is held in the nutrient solution as temperature increases as well. Combining an overly warm root zone with a bit too much irrigation and a heavy, saturated growing media is going to cause problems sooner or later.

A severe infection of Pythium can result in a completely brown and rotten root system.

2. Don’t ever overwater. Review your watering procedures. Nutrient, when applied to a substrate, displaces the air-filled pockets—then when draining fully occurs, more air is drawn down into the root system. But if watering is too frequent, the air-filled pores remain saturated, and the plant has less access to the oxygen contained in air. Overwatering is the most common cause of Pythium in hydroponics, and it seems most inexperienced growers tend to water plants to death without understanding the root system requirement for breathing and absorbing oxygen for respiration. 3. Keep the temperatures down. Maybe investing in

a solution chiller or even a bottle of ice in the nutrient tank when it’s hot is worth considering. Solution chilling to lower the risk of Pythium is probably a better option in a continually circulating solution culture system where the chilled


Maximum Yield UK | March/ April 2012

4. Maintain biodiversity in the root zone. Heavy use of sanitation chemicals was once thought to be the answer to preventing Pythium attack; however, research has shown that even with very thorough cleaning and use of disinfectants, Pythium is not always completely eradicated, and new sources of the disease are pretty much everywhere. Encouraging a healthy root zone with a highly diverse range of microbes is a more effective long-term approach. Recently disinfected hydroponic systems are devoid of useful microbes, allowing opportunists such as Pythium an open field for attack. A well-seasoned system might be a better approach, as would be the introduction of beneficial microbes. There are many thousands of species of beneficials, so natural inoculates such as fresh vermicast (worm castings) incorporated into the growing media are worth trying, as are the microbial products on the market. Hydroponic systems are often low in microbial diversity and density, particularly with regard to those species that might control root rot disease pathogens such as Pythium. However, several species of specific microbes have been shown to have potential for controlling root rot pathogen in certain crops. These microbes include Pseudomonas chlororaphis, Pseudomonas fluorescens, some species

of Bacillus, Gliocladium, Lysobacter and Trichoderma, which indicates that inoculation with beneficial microbes of the correct species could be an effective control option if carried out correctly. 5. Eliminate stress. Environmental stress is one factor that

often brings on a Pythium attack. Keeping temperatures within range; supplying plenty of oxygen and sufficient light (Pythium attack is more common under low light in certain plant species); applying correct watering practices; and reducing transplant shock are all good methods of preventing problems. Healthy plants are more able to resist and defend themselves from Pythium, while those that have been weakened or damaged will release phenolic compounds, which signal to any lurking Pythium spores that it’s a good time to attack. 6. Reduce Pythium inoculation. Unfortunately, Pythium is

pretty much everywhere in our environment. However, it is most commonly introduced on new transplants—which probably will appear symptomless—in water (well or ground water in particular); on feet, shoes or clothing; carried by animals; as wind-blown dust; or sometimes in growing media such as peat

or substrates, which might have been in contact with soil or plant matter such as compost. 7. Don’t let the gnats attack. One of the more common

methods of spread is via fungus gnats and shore flies. These tiny insects are attracted to overly damp media, and are common in some hydroponic systems. Unfortunately, the larvae of these flies not only chew on the root system, they also carry Pythium spores in their gut and mouth parts and are responsible for transmission of the disease. Fungus gnats can be controlled with commercial products or with beneficial predators, or by

Maximum Yield UK | March/ April 2012


The Pythium Predator

“When cleaning out a system or even while the crop is still developing, areas of biofilm (a layer of grime and organic matter) can build up inside the irrigation system.” symptoms. Many researchers have carried out trials into the effect of surfactants for Pythium control in hydroponics with promising results, although dose rates and the surfactant products used differ from study to study. Non-ionic surfactants (detergents) have been proven to control Pythium in nutrient solutions by having a lytic effect—they dissolve the plasma membrane of the fungus structures, killing them. Surfactants might cause quite a bit of foaming at the nutrient tank in recirculating systems, but may be worth trying—particularly if all else fails.

Sources and references

Cucumbers produce large volumes of mucilage in the root system, which attracts Pythium spores.

reducing watering, removing any rotting vegetation or covering the surface of growing media. 8. Give some thought to biofilms, root tissue fragments and mucilage. When cleaning out a system or even while the

crop is still developing, areas of biofilm (a layer of grime and organic matter) can build up inside the irrigation system. Old root fragments are a common source of Pythium infection, and can be difficult to eradicate from growing media, although oxidants such as hydrogen peroxide will dispose of organic matter if applied at a strong enough dosage. Mucilage is more difficult to manage—some crops, such as cucumber, which produce vast quantities of this root exudate material, are best not grown in recirculating systems because of this. While all roots produce some organic compounds, the buildup can become higher in recirculating systems in which there is little biodynamic diversity, as beneficial microbes are responsible for much of the breakdown of mucilage. 9. Surfactants are worth trying if a Pythium outbreak is starting to occur. While many commercial NFT growers

have experimented with the use of non-ionic surfactants in their nutrient for Pythium and other root rot pathogen control, the results are somewhat inconclusive, as many factors other than pathogens can cause similar


Maximum Yield UK | March/ April 2012

Stanghellini, M. E. and Tomlinson J A., 1987, “Inhibitory and Lytic Effects of a Nonionic Surfactant on Various Asexual Stages in the Life Cycle of Pythium and Phytophthora Species.”The American Phytopathological Society Vol.77, No. 1, pp 112-114. Seebold, I. W. and Dixon E., 2008, “Control of Pythium Root Rot in a Tobacco Float System with Surfactants.” Phytopathology Vol. 98, No. 6, pp 143. Cherif M., Tirilly,Y. and Belanger, R. R., 1997, “Effect of Oxygen Concentration on Plant Growth, Lipidperoxidation and Receptivity of Tomato Roots to Pythium F under Hydroponic Conditions.” European Journal of Plant Pathology Vol. 103, pp 255-264. Sutton, J. C., Sopher, C. R., Own-Going, T. N., Liu,W., Grodzinski, B., Hall, J.C. and Benchimol, R.L., 2006, “Etiology and Epidemiology of Pythium Root Rot in Hydroponic Crops: Current Knowledge and Perspectives.” Summa Phytopathology, Vol. 32, No.4. MY

Pint-sized Entrepreneurs by Heather Pearl

Little Growers is a horticultural education charity that works with schools, predominantly in the UK, but also worldwide, to provide children with everything they need to grow their own produce. Each school is provided with their own bespoke set-up which includes raised beds, a polytunnel, seeds and the environmentally friendly AutoPot watering systems to ensure the crops have everything they need 365 days a year.

Little Growers Project Market Stall (Pilot) Little Growers has recently extended its local projects. In addition to growing within schools, the children are now also planning and running produce market stalls within their schools. Little Growers held its first market stall September 17, 2011 in collaboration with the Co-operative Supermarket in Bagshot. The four Little Growers projects sold their produce to the community—from beetroots, gourds and turnips to herbs, sungold tomatoes and courgettes—with all produce selling out in three hours! It was a huge success and a great way to end the summer. Over £315 was raised and given to the schools to help sustain their gardening projects. The best sellers from the stall were the huge crates of rocket that had been freshly harvested that morning, as well as the cherry tomatoes, beetroots and carrots. The Little Growers staff was in awe of how enthusiastically the children took control of running the stall, organising the produce, and weighing and selling to passersby; there are definitely some mini Alan Sugars among the Little Growers! Little Growers hopes the Co-Operative Supermarket will see what a brilliant idea this is and support the projects. The long term goal of Little Growers is to have the schools’ produce branded and sold within the Co-operative alongside the organic, fair-trade and other ranges. This will mean that parents and residents can buy locally-grown produce and sustain the school projects directly. By extending the Little Growers projects from not only growing their own produce but selling it, the charity is promoting young enterprise and social entrepreneurial skills.

Little Growers South Africa – SOS Children’s Village Project The Little Growers SOS Children’s Village project in South Africa continues from strength to strength; this amazing project has truly come from nothing. The grand opening was July 27, 2011. The commercial scale polytunnels were built on derelict land that was levelled and prepared before installation of the growing project. The polytunnels are filled with AutoPot systems—they are using both the easy2grow system and the AQUAbox Spyder for raised beds. They propagated a range of summer crops including tomatoes.

The project is overseen by the housemothers who look after eight children each. They have training sessions with horticulturalists to facilitate ownership of the project and to provide them with the necessary skills they need to oversee the project. This project shows what can be achieved with hard work and determination! MY For more information about Little Growers please e-mail or visit Maximum Yield UK | March/ April 2012


by Matt LeBannister

STRONG STEMS, HEALTHY PLANTS The three main culprits of weak or stretched stems and ways to toughen them up

There are many variables that must be considered when setting out to grow consistently healthy plants. When growing indoors, gardeners must take responsibility for meeting all of their plants’ needs. However, having the right knowledge can give indoor gardeners a big advantage over outdoor growers, because while traditional outdoor gardeners are more or less at the mercy of their local soil and weather conditions, indoor growers have the ability to maximize crop potential by customizing the growing environment to meet their plants’ specific requirements.


Maximum Yield UK | March/ April 2012

“Weak stems will not transport water and nutrients efficiently throughout the plant, greatly diminishing potential yield.”

Controlling temperature indoors means there are no unexpected spring frosts or protracted heat waves, while having the ability to feed plants frequently with a nutrient solution specifically designed for each stage of growth allows the indoor gardener to fully meet the plants’ nutritional needs. Natural sunlight is replaced by light bulbs designed to mimic the sun, but also to give plants the perfect intensity and spectrum for their particular stage of growth. Plants can be watered frequently and allowed to drain, keeping them from drying out or drowning. The only real disadvantage facing indoor gardeners, in fact, is that they are in complete charge of their crops—if something goes wrong, it’s because they did something wrong, and they can’t blame it on the weather.

Weak, limp, discoloured or stretched stems are major symptoms that indicate one or more of the needs of your plants are not being met. Weak stems will not transport water and nutrients efficiently throughout the plant, greatly diminishing potential yield. They cannot support large leaves, fruit or flowers and can be damaged easily. Certain conditions affecting the overall health of the plant tend to manifest themselves as afflictions of the plant stem. Most stem problems can be treated and all can be prevented, though—with a little knowledge and foresight. The most common cause of weak or stretching stems is an inadequate source of light. When plants do not receive light of sufficient intensity for their growing phase they can begin to grow thin and

Maximum Yield UK | March/ April 2012


strong stems, healthy plants

“Nitrogen is largely responsible for the chlorophyll in leaves, making it essential for photosynthesis.”

spindly as they stretch toward the light source. The stems of plants left growing on the furthest edge of the range of a light source will often begin to reach toward the middle, and will be noticeably weaker than those directly under the light. This can be remedied a number of ways. Rotating the plants periodically so that they each get equal time directly under the light can help keep stems from stretching. Sometimes just adding reflective material—either mirrored or flat white—around the edge of the growing area can help to keep light in, or you can install an apparatus called a light mover to move the light source around over the garden, effectively distributing light evenly to all your plants. Sometimes all your plants can begin to stretch. This is most likely because the light is simply not strong enough. Fast-growing plants in their vegetative stage require lights that can provide them with 2,500 lumens/foot candles of light for 18 uninterrupted hours a day in order to maintain vigorous health and strong stems. Flowering plants need 10,000 lumens/foot candles of light for 12 uninterrupted hours a day to produce fruit and flowers to their maximum potential. Each different wattage and type of bulb will have a different output, and since light diminishes exponentially over distance, these two variables must be factored in when determining the right bulb for you and the correct distance to hang that bulb from in order to effectively light your plants. For example, plants growing 60 centimetres away from the light source are receiving


Maximum Yield UK | March/ April 2012

four times less light than plants 30 centimetres away from the light source receive. To tell how much light in lumens your plants are actually receiving from the light source, divide the light output by the distance squared. Nitrogen is another factor that is highly important in leaf and stem development as well as overall plant health. It is a macronutrient that plants need in relatively large amounts—although less so when fruiting or flowering. Nitrogen is largely responsible for the chlorophyll in leaves, making it essential for photosynthesis, and also plays a significant role in the production of certain amino acids and enzymes. When nitrogen reaches toxic levels within the plant, however, certain adverse symptoms might become pronounced. Plants might appear overly green and lush, yet growth will be stunted and fruit may have trouble setting. Stems will become weak and can be easily damaged. They will also be able to be bent over with little resistance, and the tissue in the stem that transports water throughout the plant will begin to break down, restricting the uptake of water by the plant. There are a few causes of nitrogen toxicity. There could be too much nitrogen present in the growing medium or hydroponic solution, in which case flushing the growing medium with straight pH balanced water or with a clearing solution can help rid the medium and plant of the built-up nitrogen.You should also use a quality plant nutrient formula like pine tree oil

Maximum Yield UK | March/ April 2012


strong stems, healthy plants

“Keeping your grow room well ventilated and making sure plants are not spaced too closely together can also reduce the risk of verticillium wilt.”

extract, which is a natural source of nitrogen and relatively safe compared to other nitrogen-rich nutrient additives because the risk of toxicity is low. There is another relatively common disorder that affects the stems of plants during their seedling phase, known as Pythium wilt or damping-off. Seedlings that are afflicted will seem to rot at the point where the stem and the growing medium meet. This is a fungal infection of the plant tissue that will eventually cause the stem to be unable to take up water and nutrients from the roots, causing the seedling to eventually fall over and die. To prevent Pythium wilt from afflicting your seedlings, plant them in well-drained soil with plenty of light. If the air becomes too stagnant or humid, damping-off is likely to occur. Humidity domes can be used to keep the air and root zone humid while seedlings or cuttings grow, helping to prevent the fragile roots from drying out. Humidity domes should be ventilated or removed once a day for 10 minutes to allow the seedlings or cuttings to be exposed to some dryer air, thus reducing the risk of them damping-off. Using a sterile growing medium can also help prevent Pythium wilt. To sterilize your own soil—this is best done in


Maximum Yield UK | March/ April 2012

mid-summer—simply place it in a clear plastic bag and leave it in direct sunlight. The sun will heat up the soil, killing any harmful pests and bacteria. Soil can also be baked in an oven at 177°C for 10 to 15 minutes. Adding a layer of dry material along the soil line will help to keep the surface dry and also reduces the likelihood of fungal growth. Sand, perlite or fine sphagnum moss is ideal for this. Once a couple of weeks have passed, plant stems will toughen up enough for them to no longer be at risk of contracting the damping-off fungus. Another fungal infection that can cause stems to be weak and droop is verticillium wilt. This disorder can affect plants in every stage of growth, although the symptoms of verticillium wilt will most often first appear on the lower and outer parts of the plant. Stems and leaves will become weak and begin to droop, and the interior of the stems may become discoloured. Cleanliness is the best way to prevent verticillium wilt. Thoroughly cleaning equipment between crop rotations can help, and sterilizing tools when taking cuttings is essential to prevent the spread of the fungus from one plant to another. This is important since plants are at their most vulnerable when being cut—with the stress involved, and the fact that there is an open wound created, through which the fungi could find easy access to the plant’s vital systems. Keeping your grow room well ventilated and making sure plants are not spaced too closely together can also reduce the risk of verticillium wilt. There is no cure for this infection, so plants that are noticeably afflicted must be destroyed in order to prevent the transfer of the disease to the remaining healthy plants. There are a number of reasons your plant stems might seem stretched or weak, although insufficient light intensity, nutrient toxicity and disease are the most common culprits. Keep these factors in check and you’ll go a long way toward preventing plant stem problems from ever occurring—which will lead to generations of healthy plants with strong stems. MY


The following easy-to-implement eco-solutions will help you prepare your garden for spring. Although the calendar tells us that every New Year begins in January, it’s hard to argue that from a gardener’s point of view the year begins with the first new buds of spring. But everything good that comes out of your outdoor garden at harvest time grows from the careful planning and hard work you put in months before, and early spring is the perfect time to put in the effort to ensure success in the months ahead. A small amount of planning now can help provide a continuous flow of food from your garden this coming season. This month also begins the season of dormant pruning of your fruit trees, cane berries, bush berries, grapes and roses. I recommend researching correct pruning techniques for each variety before cutting anything, due to the variety of responses from species to species and the different types of cuts to be made. Take the opportunity of plant dormancy to do hard woodcuttings. This method is the most cost-effective and foolproof way to propagate deciduous woody perennials. Try lilacs, roses, figs and grapes, to name a few. Winter is the best time to mulch and top dress but early spring works too—a thick top dress is always a good idea during winter rains. A blend of humus concentrates, guano mix, earthworm castings and organic compost will provide your soil and plants with the nutrients they need when getting ready for a new season.You can prevent erosion and protect soil structure by mulching exposed soil, especially if it is sloped. Wood chips, cardboard, straw and newspaper can all help protect bare garden soil from the power of Mother Nature.

Environmentally conscious gardeners should be aware of the affects of their garden additives. With kilometres of aisles of synthetic pesticides and fertilizers to choose from it can sometimes be hard to resist quick and easy answers, but there are solutions out there for healthy non-toxic garden systems. The biologic method of making compost extract and active aerobic compost extract will enliven any soil, from an urban backyard to monocropped industrial agricultural acreage. Any reputable local grow store should be able to provide all of the proper equipment for producing your own compost extracts to ensure the best results. Extractor bags enable you to instantly make compost extract in any type of container. Comprised of quality mesh screen, extractor bags are sized for microbial and nutrient extraction. Directions and recipes are usually included with these long-lasting durable products. If active aerobic compost extract is what you’re after, complete kits for making your own compost extract in 26, 57, 208, 1,135 and 3,785 litre sizes are available on the market now. These kits include durable, easy-to-clean components that are effective at extracting the most from your compost. Spring will soon be in the air all around us, and now is the time to get your garden ready for the warm weather and abundant harvests ahead. A well-prepared gardener is usually a successful gardener—and isn’t that the kind of gardener you’d like to be? MY

Maximum Yield UK | March/ April 2012


Salt Controlling

Buildup by Donald Lester

Knowing why and how salt accumulates in hydroponic solutions and soilless systems can help you avoid the situation in the future.

Salt buildup is a common problem for growers; in soil systems, it is characterized by an accumulation of white or off-white (sometimes even brown or gray) crystals forming on the soil surface in fields and on the surface of potting mix in pots. Salt buildup can also occur in hydroponic solutions and in soilless systems. Salt buildup can be a serious problem for plants because it affects the ability of their roots to take up water. Plants normally regulate how much water they have in their system by actively drinking through their roots. When the water surrounding the roots becomes too salty, however, the salty water does not have enough water molecules in it relative to the fresher water within the plant, so it becomes hard for the plant to suck up the few water molecules left in the salty water outside. Humans have the same problem with their cells trying to get fresh water from salty water—which is the reason a sailor lost at sea can die of thirst in the middle of the ocean. 52

Maximum Yield UK | March/ April 2012

Plants respond to excess salt in the same way they respond to conditions of drought. The common symptoms are stunting, wilting, drying of the leaves and even death. There are several reasons why salt accumulation can occur, including the use of high-salt fertilisers, a poor water source, poor water drainage, bad substrate selection or even salt-sensitive plants. These factors can occur alone or in combination. One side effect of too much salt is that it can negatively affect the pH of the soil or nutrient solution. When a weak acid or a weak base is added to a salt it is called a buffer. If the pH is not in the desired range, then buffering can make pH correction more difficult. This is one reason why growers can continue to add a pH adjuster and see quick results, but then over time they see the pH drift back to where it was before the adjuster was added. Salt buildup can be corrected by leaching, changing the water source, choosing the proper substrate, switching to fertilisers

with a low salt index, by the addition of calcium or by adapting to the salt by using plants with a high salt tolerance. Leaching and your water source In soil-based systems, salts can be leached out of the soil. Pure water can dissolve the salts and leach them out of the soil profile, but that is usually not practical in agricultural fields or large indoor cropping systems. Some growers resort to leaching salts out of the soil profile with water that is less salty. This method works, but it takes a lot more water to dissolve the unwanted salts than it would with pure water. Check the salt levels in your water source—any environmental laboratory can do this for you. Water softeners add sodium to the water, so softened water should never be used for watering plants.

“Plants respond to excess salt in the same way they respond to conditions of drought. The common symptoms are stunting, wilting, drying of the leaves and even death.”

Substrate choice Some substrates can be high in salt, so staying away from the main culprits can help avoid the problem. Coir coconut fibre can be one of the offenders, so some industry experts recommend thoroughly rinsing the coir before use to remove excess salt. Sphagnum peat and compost made from purely plant sources are both good low-salt choices. Ask for an analysis of any organic amendments that you are considering, and choose your amendments wisely. If no analysis is available, you should test a small amount of the amendment before purchasing a large quantity. When considering substrates, remember that growing media should contain a substantial quantity of large pores to facilitate good drainage. Low salt index fertilisers There are several types of salts that can build up in soils and fertiliser solutions, but sodium chloride (table salt) is arguably the most common. In fact, many fertilisers use salts as active ingredients.You can get a good indication of how much salt is in a fertiliser by looking at the salt index (SI). University studies have measured how much salt is in certain brands of fertiliser and they have been ranked accordingly. It should be noted, however, that the SI does not predict the exact amount of fertiliser or the particular formulation that could produce crop injury, although it does compare one fertiliser formulation with others regarding the relative osmotic (salt-related) effects. It also shows which higher-SI fertilisers will be most likely to cause injury to germinating seeds or seedlings if placed in close proximity. For example, a liquid 2-10-10 formula might rank 27.5, whereas a 2-20-20 might rank at 7.2. Clearly, using half the rate of 4-1010 is still saltier than using the full rate of 2-20-20.

rates of gypsum. Calcium has a more powerful electrical charge than sodium, so the application of gypsum will displace soil sodium. Irrigation then leaches the free sodium through the soil profile, thus restoring the physical properties of the soil.

Addition of calcium In soils with high sodium content, gypsum (calcium sulphate) may be applied to improve the soil structure. Managing soil sodium is really about maintaining optimum levels of soluble soil calcium—in order to amend a salty soil, sodium must be replaced with calcium, which is usually accomplished with high

Salt tolerance in plants Plants vary in their susceptibility to high salt concentrations. Salt buildup is a common complication. If excessive salt accumulation is an issue in your garden, then hopefully these tips will help you isolate and rectify the situation and avoid the problem in the future. MY Maximum Yield UK | March/ April 2012


by Beth Dumey and SteveN Goldberg

pH What to do, what not to do and why “I’m trying to test the pH of my solution to make sure my plants are getting enough nutrients. I think my pH tester is broke. Or maybe it is clogged. I’m not sure, but I’ve only had it a few weeks. I think I need to return it.” –Frustrated Hydroponicist


Maximum Yield UK | March/ April 2012

“Properly storing pH testers ensures optimal functioning and enhances their longevity.”

Chances are the pH tester does not need to be returned. Instead, applying some simple troubleshooting and storage techniques can save the hydroponicist’s time and frustration. Several influences can impact a tester’s functionality, leading to drifting readings, slow response times, environmental interference and more. Here are some common complaints and what to do about them:

“My reading keeps drifting. What can I do?” The types of sensors or electrodes in pH testers are gel-filled. You are most likely to experience drifting when measuring a relatively large volume of liquid, measuring liquid at slightly colder temperatures or testing fairly clean water. Here’s what might be happening: • Because gel-filled electrodes leak solution at a much slower rate than liquid-filled electrodes they take longer to stabilize. This slower response can be perceived as drift. • When measuring a 481 gram sample, your readings will take longer to reach equilibrium (i.e., drift than if you used a smaller volume of 85 or 198 grams. Try using a smaller sample size. • When measuring liquid that is fairly clean, carbon dioxide can cause the pH to change as the sample is allowed to sit and react with the air. This may appear as drift, but actually the CO2 is changing the pH. • In general, pH testers containing electrodes with built-in temperature sensors aren’t as responsive as separate pH and temperature electrodes.

“I don’t think my pH tester is working. It’s so slow.” The age and condition of the electrode in your pH tester can affect response times. Properly functioning, new gel-filled electrodes will go from pH seven to pH four in no more than 60 to 90 seconds. Keep in mind: • As electrodes age, they respond more slowly. • In some circumstances it is normal if your electrode is quick to respond during calibration but slower to respond during your test. • Electrodes that are dirty or dried out will respond sluggishly. If rinsing with clean water isn’t enough, warm, soapy water will work well for most organics, while low concentrations of acids work well for most inorganic material. After cleaning, a period of soaking to rehydrate the glass sensing bulb may be necessary—warm (60 to 80°C) pH four buffer works well and is easy to confirm when hydration is complete as the pH reading will be constant.

Maximum Yield UK | March/ April 2012


Troubleshooting Your pH Tester

“There seems to be interference affecting my readings. What’s happening with my tester?”

“Calibration is necessary to achieve an accurate reading. In a sense, it sets the metre at the correct level, much like a scale needs to be placed at exactly zero to produce an accurate weight.”

Be wary of electrical signals introduced into your system such as nearby electric mixers, motors, ballasts, fans, etc. These can create environmental noise and impact your readings.

“My tester doesn’t seem to be calibrating. What do I do?” Calibration is necessary to achieve an accurate reading. In a sense, it sets the metre at the correct level, much like a scale needs to be placed at exactly zero to produce an accurate weight. To calibrate, always choose a pH seven buffer solution plus at least one other pH value close to your expected measurement range. Using solutions of known pH value allows you to adjust your tester. Perform calibration before each reading or set of readings. To troubleshoot: • Be sure to calibrate with fresh, unexpired buffer solution. • Try changing the batteries and calibrating again. • Reset the tester.

“My pH tester is grimy and not working well. How do I clean it?”

pH testers with mechanically intact electrodes containing no broken parts can often be restored to normal performance by one of the following procedures: •

General cleaning: Soak the electrode in a 1:10 dilution of household laundry bleach in a 0.1 to 0.5 per cent liquid detergent solution in hot water with vigorous stirring for 15 minutes. Place electrode under warm, running tap water for 15 seconds. Soak the electrode in storage solution for at least 10 minutes. Removing salt deposits: Dissolve the deposit by immersing the electrode in 0.1 M HCl for five minutes, followed by immersion in 0.1 M NaOH for five minutes, and thorough rinsing with distilled water. Eliminating oil/grease films: Wash electrode pH bulb in mild detergent or methanol. Rinse electrode tip with distilled water. Clogged reference junction: Heat a diluted KCl solution to 60 to 80°C. Place the pH electrode into the heated KCl solution for approximately 10 minutes. Allow the electrode to cool while immersed in unheated KCl solution. Disposing of protein deposits: Dissolve the deposit by immersing the electrode in a one per cent pepsin solution with 0.1 M HCl for five minutes, followed by thorough rinsing with distilled water.

For all of these cleaning procedures, soak the electrode in storage solution for at least 10 minutes prior to use. If these steps fail to restore normal electrode response, replace the electrode.

“I’m not sure if I’m storing my pH tester correctly.” Properly storing pH testers ensures optimal functioning and enhances their longevity. However, electrodes should not be stored for longer than six months. After six months, electrodes should be rotated or replaced. For best results, always keep the pH bulb wet, preferably in a storage solution or in pH 4.01 buffer with 1/100 part of saturated potassium chloride (KCl) added. Other pH buffers or tap water are acceptable storage media, but avoid storing in distilled water or reverse osmosis water because it will deplete the hydration layer of refillable electrodes and decrease the life of nonrefillable electrodes. KCl and pH four buffers provide good conditions for mould to grow. To prevent mould from growing in storage solutions, use up to four per cent of sodium benzoate or azide in the reference fill and storage solutions. 56

Maximum Yield UK | March/ April 2012

If the electrode has not been hydrated (i.e., placed in solution for more than one hour), allow the electrode to soak in a buffer (preferably pH four) prior to standardization or measurement. This will help optimize and re-establish the thin hydration layer on the sensing bulb, which is critical to pH measurement.

The Help Desk If after applying the techniques above your pH tester still seems a bit off, it may be time to call the professionals. Many suppliers and manufacturers have technical experts available to assist you by phone, e-mail or even via live chat on their website. Write down any error messages before you call. Be ready to answer how long the problem has been going on, as well as specifics such as the temperature of the solution. Of course, if the pH tester has any cracks or physical damage, this likely is diminishing its performance. At this point, the technical expert can propose the next best steps. MY

Measuring the pH of Pure Water Common sense says: “What could possibly be so difficult about reading the pH of pure water? It should be neutral-pH seven, and there are no interferences.” In practice, it can be quite difficult and often frustrating to obtain reproducible pH values in samples with low-ionic strength. Water that has very few ionic species is said to be low in alkalinity, ionic strength, or have low conductivity/high resistivity such as distilled or deionized (DI) water. It is common to attain different pH values with new, sealed electrodes that calibrate perfectly in pH buffers when attempting to measure DI water. This is due to the varying junction potentials that develop across the reference junction. Some techniques and product recommendations for overcoming such limitations will be discussed here.

Choosing a pH electrode: More expensive double-junction and calomel electrodes have a number of advantages over traditional electrodes; however, they are generally no better than their counterparts for pure water applications. A good choice is a refillable, liquid-filled electrode, ideally made of low resistance glass. A flowing reference junction has a higher flow rate to minimize junction potentials. Sealed electrodes, usually gel-filled, are best known for their long-life due in part to the extremely slow leak rate of the reference solution. However, a fast leak rate is desirable with pure water so a pH potential can be established more quickly. This is also the reason why sealed electrodes should not be stored in DI water-the sample will accelerate the leaching of reference solution, which can not be replaced.

Electrostatic interference: Since ultra pure water is a bad conductor, it can also be a source of static potentials. These static potentials may present problems in measuring pH. To compensate for this interference, pH electrodes are available with a special shielded or grounded compartment. Such electrodes are expensive and specifically designed for measurement of ultra pure water.

Other measurement tips: • It is beneficial to measure pH in the smallest sample volume possible. Direct pH measurement in large volume samples such as drums or tanks and other samples with flowing or moving water tend to fluctuate and will require excessive stabilization time. • Addition of a tiny amount of KCl will increase ionic strength to the sample and improve response time. Only high purity KCl should be used as trace contaminants in low-grade KCl can artificially alter the pH. • Maintain good laboratory practices including using clean glassware, avoiding cross-contamination after calibration by rinsing thoroughly with DI water, using only certified calibration standards, etc. • Temperature compensation should be used during measurement and calibration. Calibrate daily at multiple pH calibration points. • Minimize exposure of your sample with air. CO2 gas absorption can actually decrease pH.

Maximum Yield UK | March/ April 2012


Use Less

Water by Dr. J. Benton Jones, Jr.

(and Grow More)

Sub-Irrigation Hydroponics. No electricity required

A number of years ago I joined a group of agronomists as we visited several research stations and commercial farms that were using various irrigation methods. One of the more interesting visits was to a research station where cotton was being irrigated by sub-irrigation using a new product called leaky pipe, placed 15-centimetres below the soil surface under each cotton row. Nearby fields were being flood irrigated. What was remarkable was that the plants receiving water by means of the leaky pipes were larger and more vigorous in appearance than those receiving water by means of flood irrigation and we were also told that water use was 30 per cent less with the leaky pipe system. However, there were two drawbacks to the system—the leaky pipe had to be replaced each year and control-fitting leaks were difficult to locate and fix.


Maximum Yield UK | March/ April 2012

In the 1960s, fresh market stake-tomato growers were experithe base of the pot, the nutrient solution being delivered to the encing financial challenges due to high production costs. Since value by gravity flow from a supply tank. I have devised similar the soils were sandy, replacement fertilisation following periods growing systems, one using 34 litre plastic storage boxes as the of rainfall was required. In addition, the underlying water table rooting vessel, and the other being constructed troughs that are had to be controlled by ditching to keep it below the rooting four-metres long, 10-centimetres wide and 18-centimetres deep. zone. However, an innovative method for growing tomato plants The level of nutrient solution in the base of the rooting boxes under such soil conditions was eventually developed, based on and troughs is maintained using an attached float value. Nutrithe ability to control soil depth in relation to the water table. A ent solution is delivered to the float value by gravity flow from a soil bench was formed, fertiliser for the crop season was applied supply tank. on the soil surface and the bench was then covered with plastic. The primary advantage of sub-irrigation is that all of the apThe water table was adjusted during the growing season in plied water and essential plant nutrient elements pass through order to keep the soil under the bench moist. The inventor, Ger- the plant, therefore no loss of either to waste and the system aldson (1963), named this system concept “quality and balance,” can be operated by gravity flow with no need for electrical since it established a nutrient-moisture gradient within the soil power. My experience with long troughs has revealed that bench. A cross-section of the soil bench gives the dimensions there exists a water-flow mechanics issue, requiring the placeand position of the applied fertilizer and the depth of the water ment of a dispensing pipe in the bottom of long (greater than table. This system not only saved the stalk-tomato growers’ busi- 1.2-metres) troughs. ness by reducing their production costs, but the tomato plants By maintaining a constant level of nutrient solution (or water) responded to the consistent nutrient element-moisture environ- in the base of the rooting vessel, roots will occupy that portion ment by producing higher yields of market-quality fruit. of the rooting medium where there exists a balance between Using this sub-irrigation principle, several colleagues and I successfully grew greenhouse tomatoes in 18-centimetres of milled composted pinebark placed in a watertight container. The required fertilizer for the season was mixed into the pinebark and an inch of water was maintained in the bottom of the box using a float value mechanism. An article describing this method for use by the home gardener appeared in the March 1980 issue of Popular Science magazine (Jones, 1980) and a research paper was published authored by Bruce et al (1980). The Scaife pipe dream growing method applied the same principle for supplying water and essential plant nutrient elements by means of sub-irrigation. A sock of sphagnum peat moss was placed into a vertical pipe fitted into an opening in a horizontal pipe of circulating nutrient solution. Scaife attributed the vigorous plant growth he obtained to what he called the carburetor effect—the aeration conditions that existed around the root Figure one: cross section of a plastic sheet covered soil bench for growing mass as illustrated in figure two, again a result of the use of tomatoes in a sandy soil, showing the position of applied fertilizer and mulch and the water table creating a moisture gradient zone where roots occupy sub-irrigation. that portion of the soil where there is a balance among water, plant nutrient There are two growing systems marketed elements and air. today that employ the sub-irrigation technique. In the one growing system, the rooting container is filled with an organic rooting medium containing sufficient “The primary advantage of sub-irrigation is essential plant nutrient elements to carry that all of the applied water and essential the plants through the growing season. plant nutrient elements pass through the By observing an indicator float, water is added by hand when needed to maintain plant with no loss of either to waste and a certain level in the bottom of the rootthe system can be operated by gravity flow ing vessel. In the other growing system, with no need for electrical power.” each rooting vessel has its own value that regulates the level of nutrient solution in

Maximum Yield UK | March/ April 2012


Use Less Water (and Grow More)

occupied water and air space. Root absorption of water and plant nutrient elements is controlled by root activity and therefore not influenced by periodic applications of either water or nutrient solution. For use in my growing systems, a dilute

nutrient solution formulation is required. I have found that a ⅓ dilution of a modified Hoagland/Arnon formulation is sufficient to meet the nutrient element needs of most plants with no need to change the formulation based on plant species or stage of growth. One essential requirement is that the level of nutrient solution in the base of the rooting vessel be kept constant, as a changing depth will adversely affect root function. Therefore, automatic depth control is essential for maximum plant performance. Con-

“The hydroponic sub-irrigation concept has great potential, currently only lacking innovative growing systems that would lend themselves to wide commercial use.”

stancy within the rooting vessel contributes to greater vegetative top growth, since the root system is stabilized and not continually growing in size. I have used various rooting media: perlite, composted milled pinebark, a 50/50 mixture of perlite and composted milled pinebark, as well as various organic soilless mixes, but perlite consistently gives the best results. The depth of the rooting medium is critical, based on its own wicking characteristics. Perlite or composted milled pinebark (46 centimetres) seems to be the optimum depth, sufficient for maintaining the proper mix of water and air within the medium while keeping the top surface dry. The hydroponic sub-irrigation concept has great potential, currently only lacking innovative growing systems that would lend themselves to wide commercial use. The savings in water and reagents compared to other hydroponic methods in use— such as flood and drain or drip irrigation—would certainly seem to justify more intensive commercial development and use. The other major advantage for the sub-irrigation technique is of course that it requires no electrical power. MY

References: Bruce, R.R., J.E. Pallis, Jr., L.A. Harper and J.B. Jones, Jr. (1980) “Water and Nutrient Element Regulation Prescription in Nonsoil Media for Greenhouse Crop Production”, Communications in Soil Science and Plant Analysis 11(7), pages 677 to 698.

Figure two: an illustration of the “Scaife Pipe Dream” rooting system in which a mesh sock is filled with an organic rooting medium that is set into a vertical stand pipe fitted into a horizon pipe of flowing nutrient solution. The air column maintained around the rooting medium sock is thought to stimulate root function, therefore vigorous vegetative plant growth.


Maximum Yield UK | March/ April 2012

Geraldson, C.M. (1963) “Quality and Balance of Nutrients Required for Best Yields and Quality of Tomatoes”, Selected Proceedings of the Florida State Horticultural Society 76, pages 153 to 158. Jones, Jr., J.B. (1980) “Construct your own Automatic Growing Machine”, Popular Science 216(3), page 87.


Grow a Bonsai From Tree seeds By Marc Alexander

Presenting key tips for growing ultra-zen bonsai trees from seeds, and adding a touch of Japanese artistry to your home dĂŠcor Growing bonsai trees is a very attractive diversion though quite challenging. Admittedly, maintaining a bonsai garden is not as easy as it seems. It takes a lot of time, care and patience to grow and sustain the trees especially when they are still young and just starting to flourish. To start you can either buy a previously grown bonsai tree or you can plant and grow your own from seeds. Although the

former is more practical and uncomplicated, you may find the latter more gratifying and fulfilling. When you plant bonsai tree seeds, take time in choosing the seeds that you will use. Remember that although bonsai trees originate from regular trees, they require different methods of nurturing.You can use seeds that grow in the wild, however commercial bonsai seeds are preferable because it is more likely they will be disease-free. Also, there are species that are easier to grow and maintain.Your choice depends on your experience in growing these trees. If you already have sufficient experience in this hobby, you may be confident enough to risk planting species that are more difficult to develop. Once you have decided which kind of bonsai tree seeds to plant, you will need to prepare the materials, foremost of which are your bonsai tree seeds.You will also need bonsai-specific soil, pellet trays, peat pellets, sealable plastic bags, bonsai pots, paper towel tray and water. Most of these materials can be bought from garden shops. Germinate the seeds by drenching them in water for 24 hours using the tray. The next step is to place the soaked seeds in paper towels that you will then seal inside sealable plastic bags. Leave them for about a week in a cold place; the refrigerator is a good option. Afterward, bring the seeds out and place them in the pellet trays. This time, gradually put warm water in the trays. Observe the seeds closely until they start to swell. Be sure the trays have holes to drain the water off so as not to drown them. Place the seeds on the peat pellet then transfer them to the pots. Fill the pots with bonsai soil. Water the newly planted bonsai seeds and keep them moist while they are in the process of growing. Place them in a spot where they can get enough (but not too much) light. When the seeds have finally grown, inspect them and separate the healthy from the frail ones. Place them in individual pots and care for them until they bloom into full-grown bonsai trees. It is not an easy task to grow bonsai trees. If you are just beginning to grow your own bonsai garden, it is best to consult those who are already experienced in this hobby.You may also want to join associations of bonsai enthusiasts so you can learn more about this craft. MY (Source:

Maximum Yield UK  |  March/ April 2012


you tell us

Peter Knobel, Dutch Pro sales director (Europe)

We recently chatted with the folks at Dutch Pro about expanding into new markets, manufacturing only what customers actually need and bringing just the essentials—like beer barrels and bar equipment—to trade shows… Maximum Yield (MY): How did your line of nutrients get started? How long have they been around? Peter Knobel: Dutch Pro is one of the pioneers (‘the old school of Amsterdam’) and is the only company and supplier for nutrients founded and based in Amsterdam. About 30 years ago some growers who didn’t want to settle for the grow and bloom stimulators available at that time started to develop specific nutrients—we ended up designing a complete line that met every demand and could fulfill all the wishes of the modern grower. MY: How are your products different today than they were when the company first started? Is it a different market today? What advances have been made in the science of fertilizers since your company started making them? 62

Maximum Yield UK | March/ April 2012

Peter: Actually the whole product line hasn’t changed much— why change a winning formula? When we started to sell our products abroad we introduced 250 millilitre versions of our Explode, Take Root and Multi Total products. We also introduced a soft-water version of our basic nutrients last year especially for the UK market. The market is much more competitive today and the demand for high-technology products has increased enormously. We are also seeing nutrient companies launch many different (and unnecessary) products to expand their range just to gain more shelf space to compete with each other. We will not expand our product line with these ‘marketing bottles’—our customers appreciate getting a better end result with a much lower investment and the use of fewer bottles. MY: What makes your products superior? Peter: Our award-winning products are stable and clear, contain organic elements, keep plants vital and green until the end of the cycle and impart a characteristic taste and fragrance. All our products are designed for every irrigation system, as well as most soil, hydro and coco set-ups. In hydro you can even reach an EC level of 2.3 without burning your plants! Our products are also

very price-competitive and highly concentrated—the dilution rate for our stimulators is 1:1000.You’ll need fewer different bottles and smaller amounts of each product to get better results than you would with most other products on the market. MY: Who are the people behind your company? Are you primarily growers, scientists or marketers? Who started it all? Peter: Dutch Pro is a team of close friends who shared their experience and love for growing plants for over 30 years. Working closely together and making optimum use of the specific skills of the individuals within the team got us where we are today. Everyone within the team has his own role and together we are able to fulfill all the roles needed to run the company. MY: Where do you make your products? What are your facilities like? Peter: Production, marketing and sales operate directly out of Amsterdam. Last year we opened a new factory for the international market—the demand for our user-friendly product lines has increased enormously in a very short time and we’re now one of the strongest up-and-coming brands in Europe. Due to the demand for our products we had been working overtime until new bottling machines were finally installed to handle the European demand. We also dispatch our products straight from our centrally located warehouse in the UK. MY: It would appear from your website that your company attends a lot of trade events throughout the year, all over the world. Is this a full-time job for someone on your staff? Do you take turns going? What does this commitment entail for the company over the course of a year? Peter: We inform visitors to our website of all trade events and we attend most of these shows but it’s always a strategic choice. These shows do have a big impact on the company due to all the preparation required. Most of the time we drive to the venue in our Dutch Pro truck loaded with marketing material, samples and stand construction—including our own bar equipment and beer barrels from Amsterdam! The responsibility for coordinating all this is in the hands of one person, assisted by the manager responsible for the country where the trade show is being held.

and the sale of vegetable, fruit, herb and flower seeds was a natural fit for us. Our products can be used for all kind of plants— my palm trees, for instance, are growing better and flowering much more after using our products than you might expect in our climate! These days our seed displays and products are also available in garden centres. We want to stay close to our background—the trend today is that nutrient manufacturers start to add products that they don’t manufacture themselves, but buy from the same source as everybody else. Even some wholesale companies have started to market their own line of nutrients. We only do what we specialize in—we manufacture a highly concentrated user-friendly product line of nutrients at very competitive prices. As Dutch Pro we also decided not to implement any price increases so we could keep our products available for all our customers at every income level. MY: What’s the next big thing for Dutch Pro? Peter: Our next step will be to address the demand for our products from markets outside Europe. MY

MY: I see your company manufactures fertilizer and sells seeds—are these two particular areas a good fit? Why seeds and fertilizer as opposed to fertilizer and grow media, or fertilizer and potting supplies? Peter: The choice to combine the manufacturing of nutrients Maximum Yield UK | March/ April 2012




Pythium is the genetic name for over 50 species in the class Oomycetes, of which only a few are common on hydroponic crops.

pH testers containing electrodes with built-in temperature sensors aren't as responsive as separate pH and temperature electrodes.



The most common cause of weak or stretching stems is an inadequate source of light.


You can prevent erosion and protect soil structure by mulching exposed soil, especially if it is sloped.

Plants respond to excess salt in the same way they respond to conditions of drought. The common symptoms are stunting, wilting, drying of the leaves and even death.

Some plants—such as cucumbers in solution culture— are more prone to Pythium attack than others.

7. 8.


Properly functioning, new gel-filled electrodes will go from pH seven to pH four in no more than 60 to 90 seconds.

To tell how much light in lumens your plants are actually receiving from the light source, divide the light output by the distance squared.

9. 64


Maximum Yield UK | March/ April 2012

Sodium chloride (table salt) is arguably the most common salt that builds up in soils and fertilizer solutions.

IndustrY’s Latest


The Phat Filter Now Available in Holland

International Growers Supply is proud to welcome Dutch Lighting Solutions as its new Phat Filter distributor in Holland. The Dutch wanted the genuine Phat Filter brand back in Holland and now they have it. Ask your local retailer to contact Dutch Lighting Solutions at +31 (0) 162-521026 or visit The Euro size Phat Filters are now in stock and shipping.

AutoPot’s Commercial Trial Goes Live

AutoPot’s commercial trial at Valley Grown Nurseries is now in operation. The trial was set up at the end of December 2011 and is already thriving. There are 88 pots using 44 AutoPot easy2grow systems growing 44 plants of two varieties of peppers—the Palermo pepper and the California Block red. AutoPot would like to thank Canna and Gold Label for providing the coco for this trial. The trial is being monitored 24 hours a day with live streamed video to Here you can see time-lapse photography and narrated videos from the trial. Aeroponic technology is also being utilised to demonstrate how effective the AutoPot systems are even when a medium is not used. Valley Grown Nurseries is one of the largest commercial nurseries in the country, supplying peppers to major supermarket chains including Waitrose. Keep reading Maximum Yield UK and stay tuned to for ongoing trial results, tips and advice on how to get the most from one of the market leading growing systems in the UK.

You’re Invited to ‘Grow Like A Pro’ with Maximum Yield at the 2nd Annual Denver, Colorado Indoor Gardening Expo!—March 11, 2012 Maximum Yield’s Indoor Gardening Expo Tour is kicking off in Denver, Colorado March 11, 2012. Take a break from ‘life as you know it’ in this vibrant city and plan to attend this world-class industry event. Hundreds of industry experts will be on hand to offer their tips and tricks, and educate you on the latest products and innovations our industry has to offer. Visit for full event details.

Free Digital Subscriptions to Maximum Yield UK

We are excited to announce that we are now offering free digital subscriptions to Maximum Yield UK. Subscribe now by simply filling out the form at Don’t miss one more issue of Maximum Yield. Subscribe today!

Maximum Yield UK | March/ April 2012





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Maximum Yield UK | March/ April 2012

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Maximum Yield UK | March/ April 2012


Hybrid Hydroponics Indoor growers in Europe have devised a system that produces fat plants in small spaces. This hybrid hydro set-up could be the ideal system for you.

Bumble and Bumble – Star Pollinators in the Greenhouse Honeybees are generally thought of as the most common pollinator but bumblebees may be better for pollinating seed and food crops. Find out what makes them effective indoor pollinators.

LEDs – Making Your Investment Worthwhile Spend your grow light dollars wisely with these tips that serve to help you navigate the LED maze with ease.

Talking Shop With… Get to know your local hydro shop. We could feature your favourite grow gurus in the next issue. Recommend your favourite shop to be featured in Maximum Yield UK by e-mailing Maximum Yield UK (May/June) will be available in May for FREE at selected indoor gardening retail stores across the UK and on Subscriptions are available at

Maximum Yield UK | March/ April 2012


MAXIMUM YIELD distributors

1st Hydroponics Unit 5 K-Line House, West Rd. Ipswich, Suffolk UK IP3 9FG Tel: +44 (0) 1473 279829 21st Century Garden Unit # A6., Bounds Green Ind. Es., Ringway London, Greater London UK N11 2UD Tel: +44 (0) 2083 614659 3 Counties Hydroponics Unit 52, Robert Court Ind.E s. Britten Rd. Reading, Berkshire UK RG2 0AU Tel: +44 (0) 1189 874758 3 Counties Hydroponics The Lodge, 113 Invicta Rd. Dartford, Kent UK DA2 6AY Tel: +44 (0) 1322 273444 3 Counties Hydroponics Unit 13., Chiltern Bus. Ctr. Cowley, Oxford UK OX4 6NG Tel: +44 (0) 1865 771747 3 Counties Hydroponics Unit #11, Olds Close, Olds Approach Watford, Herts UK WD18 8RU Tel: +44 (0) 1923 774486 3 Countries Hydroponics Unit 12., Yew Tree Ind. Es., Mill Hall Aylesford, Maidstone UK ME20 7ET Tel: +44 (0) 1622 790456 3 Countries Hydroponics Unit 10., Woodley Yard Cherstsey Bridge Rd. Chertsey, Surrey UK KT16 8LF Tel: +44 (0) 1932 562174 3 Countries Hydroponics Unit 9., Galley Hill Yard Waltham Abbey, Essex UK EN9 2AG Tel: +44 (0) 1992 652301 A-Zee Hydro Ltd. Unit C4, Suttons Bus. Ctr.New Rd. Rainham, Essex UK RM13 8DE Tel: +44 (0) 1708 551199 Acorn Horticulture 65 Deep Ln.  Sheffield, UK S5 0DU Tel: +44 (0) 1142 458581 Addloes Lighting & Hydroponics 16-A Maple Rd., Winton Bourmouth, Dorset UK BH9 2PN Tel: +44 (0) 1202 524525; Allbright #6., The Rise Edgware, Middlesex UK HA8 8NR Tel: +44 (0) 2089 582426 Amazing Garden Supplies (Bridgend) Unit 6 Eastlake Close., Litchard Ind. Es. Bridgend, South Wales UK CF31 2AL Tel: +44 (0) 1656 663030 Amazing Garden Supplies (Bristol) Unit 3 Moravian Bus.Pk., Moravian Rd. Kingswood, Bristol UK BS15 8NF Tel: +44 (0) 1179 605566 Anglia Hydroponics 62 A Straight Rd. Boxted, Colchester, Essex UK C04 5RD Tel: +44 (0) 1206 272677 Aquaculture Unit 79 (A) Carlton Ind. Es. Barnsley, South Yorkshire UK S71 3HW Tel: +44 (0) 8456 445544 Aquaculture Unit 3, Asher Ln. Bus. Pk. Asher Ln. Ripley, Derbyshire UK DE5 3RE Tel: +44 (0) 8456 445544


Maximum Yield UK | March/ April 2012

Listed alphabetically by shop name.

Aquaculture Unit #3, Pkwy One, Pkwy Dr. Sheffield, South Yorkshire UK S9 4WU Tel: +44 (0) 8456 445544 Aquatech Horticultural Lighting Unit 3F, Spa Fields Ind. Es. New St. Slaithwait Huddersfield, West Yorkshire UK HD7 5BB Tel: +44 (0) 1484 842632 Ashton Hydroponics Ltd. Unit 3 Park Parade Ind. Es. Welbeck St. S. Ashton-Under-Lyna, Manchester UK O4L 67PP Tel: +44 (0) 1613 391673 Aztec Garden Unit 1A Roughan Ind.Es. Bury St. Edmunds, Suffolk UK IP30 9ND Tel: +44 (0) 1359 271876 Basement Lighting Ltd. Unit #3, The Old Maltings, George St. Newark, Nottinghamshire UK NG24 1LU Tel: +44 (0) 1636 650189 Big Stone River Garden Center Unit #1 East Gate Grimsby, Lincolnshire UK DN3 29BA Tel: +44 (0) 1472 241114 Blooming Borders Unit 3, Borders Bus Pk. Longtown Carlisle, Cumbria UK CA6 5TD Tel: +44 (0) 1228 792587 Bradford Hydroponics 9597 Manningham Ln. Bradford, West Yorkshire UK BD1 3BN Tel: +44 (0) 1274 729205 Branching Out Unit #E, The Old Brewery, Durnford St. Ashton Gate, Bristol UK BS3 2AW Tel: +44 (0) 1179 666996 Bright Green UK Ltd. 42-44 Princess Rd., Hull, Yorkshire UK HU5 2RD Tel: +44 (0) 1482 341925 Brit Crops Ltd Unit 9 OJ’s Ind. Pk.Claybank Rd. Portsmouth, Hampshire UK PO3 5SX Tel: +44 (0) 2392 669111 Britlite Hydroponics Unit 11 Roman Ind. Es. Croydon, UK CRO 2DT Tel: +44 (0) 2086 834424 Chrissie’s Garden Unit 33 Portsmouth Enterprise Ctr. Quartermain Rd. Portsmouth, UK PO3 5QT Tel: +44 (0) 2392 667887 Clever Green 35 Ketley Bus. Pk. Waterloo Rd., Telford, Shropshire UK TF1 5JD Tel: +44 (0) 1952 257200 Crofters Bio Gardens Unit 2, Bloomsgrove Ind. Es.Ilkeston Rd. Radford, Nottingham UK NG7 3JB Tel: +44 (0) 1159 782345 Discount Hydroponics 1 Bus. Bldg. Waltergrave St. Hastings, East Sussex UK TN34 1SJ Tel: +44 (0) 1424 428186 Eastbourne Hydroponics 47 Upperton Rd. Eastbourne, East Sussex UK BN21 1LT Tel: +44 (0) 1323 732241

Eighteen Twelve Ltd. Unit 11 Whitehall Properties Towngate Wyke, Bradford UK BD12 9JQ Tel: +44 (0) 1274 694444 Elements Hydroponic Center 44 Auster Rd. Clifton Moor, York UK YO30 4XA Tel: +44 (0) 1904 479979 Enhanced Urban Gardening 152 London Rd. Workingham, Berkshire UK RG40 1SU Tel: +44 (0) 1189 890510 Esoteric Hydroponics Ltd. 8 Martyr Rd. Guildford, Surrey UK GU1 4LF Tel: +44 (0) 1483 596484 Garden Secrets UK Ltd. Unit 3 Hollybush Est. Whitchurch, Cardiff UK CF14 7DS Tel: +44 (0) 2920 651792 Great Stuff Hydroponics 24 Collingwood Ct. Riverside Park Ind. Es. Middlesbrough, UK TS2 1RP Tel: +44 (0) 1642 224544 Great Stuff Hydroponics 30 C Ellemeres Ct. Leechmere Ind. Es. Sunderland, UK SR2 9UA Tel: +44 (0) 1914 474098 Green Daze Hydroponics Ashington Unit 9 Waterside Ct. North Seaton Bus. Pk. Ashington, Northumberland UK NE63 0YG Tel: +44 (0) 1670 818003 Green Daze Hydroponics Gateshead 10 Wellington St. Gateshead, UK NE8 2AJ Tel: +44 (0) 1914 789107 Green Finger 190 Hessle Rd. Hull, East Yorkshire UK HU3 3BE Tel: +44 (0) 1482 222425 Green Spirit Hydroponics Ltd 8-10 Stanley St. Sheffield, UK S3 8HJ Tel: +44 (0) 1142 753353 Green Stream 12-14 Vivian Rd. Harbourne, Birmingham UK B17 ODS Tel: +44 (0) 1214 262675 Green World 1618 Market Vaults Scarborough, UK YO11 1EU Tel: +44 (0) 1723 370900 Greener than Life 575- 577 Holderness Rd. Hull, East Riding UK HU8 9AA Tel: +44 (0) 1482 374201 Greenfinger Ltd. T Marchant Est., 42-72 Verney Rd. Unit #59 Bermondsey, London UK SE16 3DH Tel: +44 (0) 2073 940629 Greenfinger Ltd. 16-18 Park Rd., Unit 3 Park Works Kingston, Surrey UK KT2 6BX Tel: +44 (0) 2085 463444

Greengrass Indoor Gardening Supplies Unit 5A Alexander Ct. Hazleford Way Newstead, Nottingham UK NG15 0DQ Tel: +44 (0) 1623 755055 Greenhouse Effect Unit 2 Eagle Farm Cranfield Rd. Wavendon, Milton Keynes UK MK17 8AU Tel: +44 (0) 1908 585283 Greenleaf Systems Unit 26, Millers Bridge Ind. Es., Seymour Bootle, Liverpool UK L20 1EE Tel: +44 (0) 1519 331113 Greens Horticulture Unit F Totterdown Bridge Est, Albert Rd. St. Philips Bristol, Somerset UK BS2 0XH Tel: +44 (0) 1179 713000 www. Greensea Hydroponics Unit 1G. Gregory Rd. Mildenhall, Bury St. Edmonds, Suffolk UK IP28 7PP Tel: +44 (0) 1638 715350 Greenstream Hydroponics 12-14 Vivian Rd. Birmingham, Harbourne UK B17 0DS Tel: +44 (0) 1214 262675 Greenthings Hydroponics Unit 1, Adjewhella Chapel Barriper Camborne, Cornwall UK TR14 0QW Tel: +44 (0) 1209 611870 Grotec Hydroponics 393 Manchester Rd., Rochdale, Greater Manchester UK OL11 3PG Tel: +44 (0) 1706 750293 Grotech Ltd. Unit 21. Saddlers Hall Farm, London Rd. Basildon, Essex UK SS13 2HD Tel: +44 (0) 1268 799828 Grow 4 Good Ltd. 22i Beehive Workshops Durham, UK DH1 2X1 Tel: +44 (0) 1913 757667 Grow Den 2 Horthfield Rd., Rainham, Kent UK ME8 8 BJ Tel: +44 (0) 1634 239333 Grow Shaw 96-98 Shaw Heath Rd., Stockport, Manchester UK SK3 8BP Tel: +44 (0) 8452 725266 Grow Zone UK 40 Surf View, Camullas Way Newquay, Cornwall UK TR7 1PP Tel: +44 (0) 1637 850488 GroWell Coleshill Units 8-11 Coleshill Trade Park, Station Rd. Coleshill, Birmingham UK B46 1HT Tel: +44 (0) 8453 442333 GroWell Dudley Unit 52 Enterprise Trad. Es. off Pedmore Rd. Brierly Hill, Dudley UK DY5 1TX Tel: +44 (0) 8453 456991 GroWell Fullham 1 Royal Parade 247 Dawes Rd. Fullham, London UK SW6 7RE Tel: +44 (0) 8453 445174

GroWell Hockley Heath Ivy House Farm, Grange Rd. Hockley Heath, Solihull UK B94 6PR Tel: +44 (0) 8433 571640 GroWell Mail Order Division PO Box 3255 Warwick, UK CV34 5GH Tel: +44 (0) 8453 455177 Growing Life #6 Newington Green Rd. London, UK N1 4RX Tel: +44 (0) 2070 339541 Happy Daze Hydroponics Unit 4 Craven Court Hedon Rd. Hull, UK HU9 1NQ Tel: +44 (0) 1482 224299 Happy Gardens Ltd. Unit 9, Kelham Bank Ind Es., Kelham St. Doncaster, South Yorkshire UK DN1 3RE Tel: +44 (0) 1302 761386 HFM Pyrotechnics Ltd. 165A Londford Rd. Cannock, Staffordshire UK WS11 OLD Tel: +44 (0) 1543 500800 Hi9THC Unit 3. Rope Walk. Coach Rd. Whitehaven, Cumbria UK CA28 7TE Tel: +44 (0) 7821 914646 High Street Hydroponics Unit 56 Hebden R., Berkley Ind.Es., Scunthorpe, North Lincolnshire DN15 8DT Tel: +44(0) 1724 857191 Holland Hydroponics 17 Rondin Rd., Ardwick, Greater Manchester UK M12 6BF Tel: +44 (0) 8458 720570 Holland Hydroponics Handbridge Mill 5 Parliament St. Burnley, Lancashire UK BB11 5HG Tel: +44 (0) 8458 720590 Home Grower Ltd. Unit 8, Oak Court, Crystal Dr. Smethwick, West Midlands UK B66 1QG Tel: +44 (0) 1215 411446 Web: Huyton Hydroponics & Gardening Supplies Huyton, Mersey Side UK Tel: +44 (0) 1514 820101 Hydro 1 Stop Unit 35 Deykin Pk. Ind. Es. Deykin Ave. Aston, Birmingham UK B67HN Tel: +44 (0) 1213 280876 Hydro Hobby Unit 4 Brook Farm, Stoneleigh Rd. Gibbet Hill, Coventry UK CV4 7AB Tel: +44 (0) 2476 414161 Hydro Station Ltd. Unit 10 Hillfoot Ind. Es. Hoyland Rd. Sheffield, South Yorkshire UK S38AB Tel: +44 (0) 1142 491636 Hydrodragon Ltd. 113-115 Alfred St. Roath Cardiff, South Glamorgan UK CF24 4UA Tel: +44 (0) 2920 490333

Hydroglo Ltd. The Top Store South Rd., Towerhamlets Dover, Kent UK CT17 OAH Tel: +44 (0) 1304 203199 Web: Hydrogrow Systems Ltd. Unit 7, Acton Bus. Pk., Fields Farm Rd. Longeaton, Nottingham UK NG10 3FZ Tel: +44 (0) 1159 730007 Web: Hydrolite UK Ltd. 215 Denman St., Radford, Nottingham UK NG7 3PS Tel: +44 (0) 1159 785556 Hydroponic Corporation Unit 20, Deeside Ind. Es., Zone 1 Deeside, Flintshire UK SH5 2LR Tel: +44 (0) 1244 289699 Hydroponica Ltd. 130 Doncaster Rd. Wakefield, Yorkshire UK WF1 5JF Tel: +44 (0) 1924 362888 Web: Unit 24, Port Talbot Business Units Addison Road Port Talbot, UK SA12 6HZ Tel: +44 (0) 1639 888891 Hydropower 300 Holton Rd. Barry, Vale Of Glamorgan UK CF63 4HW Tel: +44 (0) 7725 551479 Hydrosense 47 Scarrots Ln. Newport, Isle of Wright UK PO30 1JD Tel: +44 (0) 1983 522240 Hylton Hydro Rockington Nursery Blackness Rd. Sunderland, UK SR4 7XT Tel: 01 9155 18453 Hytec Horticulture Old Wales Wood Colliery, Mansfield Rd. Sheffield, UK S26 5PQ Tel: +44 (0) 1909 772872 Kernow Grow Ltd. 11 D. Kernick Ind. Es. Penryn, Cornwall UK TR10 9EP Tel: +44 (0) 3300 104420 King Of Green 18-24 Saint Helens Rd., Westcliff on Sea Westcliff, Essex UK SS0 7LB Tel: +44 (0) 1702 347536 Kitbag Hydroponic Warehouse 22 Pool Bank St. Nunaeton, Warwickshire UK CV11 5DB Tel: +44 (0) 2476 641033 Lancaster Hydroponics Unit 18 Lansil Ind.Es., Caton Rd. Lancaster, Lancashire UK LA1 3PQ Tel: +44 (0) 7961 279279 Lothian Hydroponics 172 S Mid St. Bathgate, West Lothian UK EH48 1DY Tel: +44 (0) 1506 650501 Makes Sense Grow Shop The Annex Rear of #20, Barden Rd. Tonbridge, Kent UK TN9 1TX Tel: +44 (0) 1732 507201

Maximum Yield UK | March/ April 2012


MAXIMUM YIELD YIELD MAXIMUM distributors distributors

Manchester Hydroponics Unit 1A, Reliance St. Newton Heath, Manchester UK M40 3AG Tel: +44 (0) 1616 887333 Matilda’s Planet 1 Green Pl. Kenfig, South Wales UK Tel: +44 (0) 7895 567843 Mellow Yellow Hydro Ltd. Unit B1A Towngate Works., Dark Ln. Mawdesley, Lancashire UK L40 2QU Tel: +44 (0) 1704 822609 Mile End Hydroponics 265 Wick Rd. London, UK E9 5DG Tel: +44 (0) 2085 330497 Mousehold Garden Center 63 Mousehold Ln. Norwich, Norfolk UK NR7 8HP Tel: +44 (0) 1603 413272 Mr. Beam Hydro Rose Grove Selby Rd. Askern, Doncaster UK DN6 0ES Tel: +44 (0) 1302 708297 New Age Hydroponics Unit 1 Albert Pl., Albert Mill Lower Darwen, Lancashire UK BB3 OQE Tel: +44 (0) 1254 661177 New Leaf Hydroponics 1 Horsewater Wynd, Hawkhill, Dundee UK DD1 5DU Tel: +44 (0) 1382 202556 Norfolk Lights & Hydroponics Centre Ltd. Unit 2 Guardian Rd., Ind. Es. Norwich, Norfolk UK NR5 8PF Tel: +44 (0) 1603 666199 North Devon Hydroponics Unit 4 Abbey Rd. Barnstaple, Devon UK EX31 1JU Tel: +44 (0) 1271 314999 NuGreen Hydroponics Unit 4 Stirchley Trad. Es., Hazelwell Rd. Stirchley, Birmingham UK B3O 2PF Tel: +44 (0) 1216 855900 One Stop Grow Shop Unit 8, Fenton Ind. Es., Dewsbury Rd. Fenton, Stroke-On-Trent UK ST4 2TE Tel: +44 (0) 1782 212000 Planet Hydro Unit 11 NorthBridge Works., Storey St. Leicester, Leics UK LE3 5GR Tel: +44 (0) 1162 510800 Plant Life Unit 11 Riverside Wy., Ravensthorpe Ind Es. Dewsbury, West Yorkshire UK WF13 3LG Tel: +44 (0) 1924 492298 Plantasia Brill View Farm Ludgershall Rd. Bicester, Oxfordshire UK OX25 1PU Tel: +44 (0) 8707 555225 Progrow 5 Westwood Units, Alphinbrook Rd. Marsh Barton Trad. Es. Exeter, Devon UK EX2 8QF Tel: +44 (0) 1392 276998


Maximum Yield UK | March/ April 2012

Listed alphabetically by shop name.

Rootzone Hydroponics Ltd. Unit 2 & 3., The Green Bus.Ctr., The Causeway Staines, Middlesex UK TW18 3AL +44 (0) 1784 490370 Sale Hydro 71 Dane Rd., Sale Manchester, Lancashire UK M33 7BP Tel: +44 (0) 1619 739899 Email: Sea of Green UK 25 Eastcott Hill Swindon, Wiltshire UK SN1 3JG Tel: +44 (0) 1793 617046 Somerset Hydro Unit 14., Yeovil Small Bus. Ctr. Houndstone Bus Pk. Yeovil, Somerset UK BA22 8WA Tel: +44 (0) 1935 420720 South Coast Hydroponics Unit 8., Enterprise Ind. Es., Enterprise Rd. Horndean, Portsmouth UK PO8 0BB Tel: +44 (0) 2392 598853 Southern Hydro Centre 9 Mamesbury Rd. Southampton, Hampshire UK S01 SFT Tel: +44 (0) 2380 704080 Southern Lights #1 25 Fratton Rd. Hampshire, UK PO1 5AB Tel: +44 (0) 1705 811822; Southern Lights #2 19A Grace Hill. Folkestone, Kent UK CT20 1HQ Tel: +44 (0) 1303 210003; 44 (0) 1303 252561 St Albans Hydroponics Unit 5 London Rd., Bus.Pk., 222 London Rd. St Albans, UK AL1 1PN Tel: +44 (0) 1727 848595 Starlite Systems 226 Albert Rd., Plymouth, Devon UK PL2 1AW Tel: +44 (0) 1752 551233 Sub-Garden Supplies 45-J Leyton Industrial Village, Argall Ave., Leyton, London UK E10 7QP Tel: +44 (0) 2085 399563 Sunrise Hydroponics 127 Newcastle St., Burslem. Stoke on Trent, Staffshire UK ST6 3QJ Tel: +44 (0) 1782 813814 The Green Machine Ltd. Unit 1A., Felin Puleston Ind.Es., Ruabon Rd. Wrexham, UK L13 7RF Tel: +44 (0) 1978 265090 The Grow Den 2 Hothfield Rd. Rainham, Kent UK ME8 8BJ Tel: +44 (0) 1634 239333 The Grow Den Ltd. Unit 13., Eaves Ct., Eurolink Com.Pk., Bohan Dr. Sittingbourne, Kent UK ME10 3RY Tel: +44 (0) 1795 426264 The Head Gardener Unit 11, Barton Bus. Pk. Eccles, Manchester UK M3O OQR Tel: +44 (0) 1617 079860 The Home Grower Unit 8., Oak Ct. Odbury, West Midlands UK B66 1QG Tel: +44 (0) 1215 411446

The Hydroponic Warehouse Unit 15., Bay Airport Ind.Es., Kingston Pk. Newcastle, Tyne and Wear UK NE3 2EF Tel: +44 (0) 1912 862045 The Inner Garden Ltd. Unit 14., Cornish Wy., West, Galmington Taunton, Somerset UK TA1 5NA Tel: +44 (0) 1823 274791 The Persy Grow Shop 4 Kings Mews. Brighton, East Sussex UK BN3 2PA Tel: +44 (0) 1273 777335 The Plant Pot 69 Ratcliffe Gate Mansfield, Nottinghamshire UK NG18 2JB Tel: +44 (0) 1623 422711 Toddington Hydroponics Center Griffin Farm Unit 9., Toddington Dunstable, Bedford UK LU5 6BT Tel: +44 (0) 1582 664765 Triangle Hydroponics 31B., The Triangle Bournemouth, Dorset UK BH2 5SE Tel: +44 (0) 1202 556661 U Grow London Studio12, Imperial Studios, 3-11 Imperial Rd. London, UK SW6 2AG Tel: +44 (0) 2073 843388 Warehouse Hydroponics Bank Quay Trading Est., Slutchers Ln. Warrington, Cheshire UK WA1 1PJ Tel: +44 (0) 1925 637837 ireland Northern Lights 9 Dunluce St. Larne Antrim, Northern Ireland BT40 1JG Tel: +44 (0) 2828 278485 The Grow Shop 14 Brews Hill Nauan, Co. M Fath Ireland OLI Tel: +44 (0) 1772 204455 scotland Progrow Scotland Unit 6., Nasmyth Square Houston Ind.Es. Livingston, West Lothian Scotland EH5 45GG Tel: +44 (0) 1506 430830 Abergreen Horticulture Ltd Arch 8 Palmerston Rd. Aberdeen, Granpian Scotland AB11 5RE Tel: +44 (0) 1224 574737 Kingdom Hydroponics Unit #12 Carbery Pl., Mitchelson Ind. Es. Kirkcaldy, Fife Scotland KY1 3NE Tel: +44 (0) 1592 655611 Hydra Hydroponics 41 Tower St. Edinburgh, Scotland EH6 7BN Tel: +44 (0) 1315 611332 Glasgrow 15 Parnie St. Glasgow, Scotland G15RJ Tel: +44 (0) 1415 527522 EZ Grow Perth 77 Scott St. Perth, Scotland PH2 8JR Tel: +44(0) 7521 597308


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Maximum Yield UK | March/ April 2012


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Maximum Yield UK March 2012  
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Hydroponics gardening resources by Maximum Yield, a free how-to hydroponics gardening and indoor gardening bi-monthly magazine that is distr...