These easy-to-grow, easy-to-sell performers will keep shoppers dancing in the aisles over their full blooms and vibrant hues. Naturally compact Conga Series Calibrachoa now offers a full color lineup with all the most popular solid colors, plus exciting bicolors to kick up your quart and color bowl offerings at retail. Book it today.
Lighting
and
Energy Costs
(Above) Knowing how electricity impacts energy costs helps you optimize your greenhouse lighting. | 10
Lighting research update. See page 34.
How they work together in IPM.
BY DRS. MICHAEL BROWNBRIDGE AND ROSE BUITENHUIS
8 Business Issues 10 Lighting strategies to control energy costs. Technology Issues 12 A new pepper weevil strategy is being assessed. HPS vs LED 14 Which is best for you?
challenges 30 The plant’s perspective on supplemental lights.
Recirculation of nutrients
Progress in our industry is always a team effort.
BY DR. CHEVONNE CARLOW
BY GARY JONES
Photo Courtesy Dr. Xiuming Hao
A Larger, Looming Labour Challenge
The best grower in Canada working with the most high-tech facilities with only premium varieties still needs one important factor in place before they can harvest and market a profitable crop.
Good labour.
Farming is as much about people as it is about plants. Even the most automated of greenhouses requires skilled trades people and highly trained operators to keep things running efficiently.
The Canadian Agricultural Human Resource Council (CAHRC) recently hosted an AgriWorkforce Roundtable to discuss challenges and possible solutions to address the critical – and growing – agricultural labour shortage.
Marc Smith, the retired assistant director of the New York State Agricultural Experiment Station in Geneva and senior extension associate, offered an international perspective on shared agricultural labour challenges being experienced in the U.S. and Canada.
Smith started off by identifying several trends in the U.S. agricultural labour sector:
• Regardless of government policy, people seeking employment in agriculture will be scarce.
• Economic and other motivations to develop and adopt labour-saving technologies are growing.
• Political and economic pressures will force minimum wages higher in many states.
• Perception of agriculture as an unattractive field for careers is a perennial challenge.
“In Canada the gap between labour demand and the domestic workforce in agriculture has doubled from 30,000 to 59,000 in the past 10 years and projections indicate that by 2025, the Canadian agri-workforce could be short workers for 114,000 jobs,” notes CAHRC communications and marketing specialist Theresa Whalen. “This was a key finding of Labour Market Information (LMI) research by CAHRC entitled Agriculture 2025: How the Sector’s Labour Challenges Will Shape its Future.”
That report noted that “among commodities, the ‘greenhouse, nursery and floriculture’ industry will continue to have the largest labour gap. With an expected gap of 27,000 workers in 2025, this commodity group will account for nearly one-quarter of the sector’s labour gap.”
Several years ago an Ontario cucumber grower emphasized to me how valuable off-shore labour was to the industry; there were simply not enough local workers willing to work in agriculture.
Foreign temporary workers are an essential resource. It’s a win-win-win situation – for the economy, for the employers and for the employees. Greenhouse
Sound familiar?
He then related how one of his long-time offshore workers was not returning this particular year, but for a very good reason. The worker had saved enough money working in Canada for several years to be able to invest in his own farm back home to the point where it had become a full-time and sustainable business. That’s only one example of how the program is valued by the temporary workers.
All advertising is subject to the publisher’s approval. Such approval does not imply any endorsement of the products or services advertised. Publisher reserves the right to refuse advertising that does not meet the standards of the publication.
Open House for Ontario Poinsettia Trials
One of North America’s largest poinsettia trials is hosting an open house next month.
The Ontario Poinsettia Trials will welcome growers and retailers on Nov. 22 from 10 to 3 (lunch provided) at Jeffery’s Greenhouses, Plant 2, located at 2411 Fourth Ave. in Jordan, Ont.
The trials will compare growing habits, height and vigour, among other traits.
On hand will be the technical representatives from each of the four companies participating in these trials.
A short speaker program will cover propagation, growing on, finishing, pest control, and the varieties, along with a panel discussion.
The trials coordinator is Melhem Sawaya of Focus Greenhouse Management. For more information, contact him at 519-427-8440 or mel@focusgreenhousemanagement.com.
More information was included in a feature last month – “Ontario trials offer pointers on points” –that has also been posted greenhousecanada.com.
BIG BOOST FOR FLOWER EXPORTS
Canadian flower exports are getting a boost. Flowers Canada Growers is receiving $393,070 under the Growing Forward 2 AgriMarketing program.
The investment will allow FCG to develop standardized training protocols for flower growers on Canada’s new export certification program for greenhouse-grown plants. This will ensure workers and managers understand and comply
THE NUMBERS
Percentage of people in 17-country survey (Canada included) that do gardening or yard work at least once a week.
with the new program. The funding will also help FCG increase its market share domestically and internationally through various marketing activities. “Canadian flower growers, many of whom are family owned farms, continue to seek opportunities to grow their exports,” said FCG executive director Andrew Morse. “This assistance will play a critical role in helping Canadian farmers reach new markets, and grow
the local economy.”
Floriculture is an important part of the horticultural industry, with more than 1900 growers producing 28 per cent of the Canadian horticultural production. In 2016, ornamental product sales (including greenhouse flowers and plants, nursery products and sod products) totalled $2.3 billion. That includes $1.5 billion from greenhouse flower and plant sales (and resales).
This non-repayable contribution will help FCG retain and expand their market, and boost exports to the United States, leading to good job creation as well as consumer access to a wide variety of competitively priced indoor plants and cut flowers in Canada.
These investments are made through the the federal Growing Forward 2, AgriMarketing Program, a five-year, $341-million initiative.
23% of Canadians surveyed trust the government food inspection system.
24% 93% VS
people in 17-country survey (Canada included) that don’t garden.
Percentage of Canadians in a recent survey who know a little, very little or nothing at all about farming practices.
Percentage of Canadians believe Canadian food is amongst the most affordable in the world today.
13% 69% 46% of Canadians surveyed are concerned about the use of pesticides in crop production.
Percentage of Canadians surveyed are concerned about the rising cost of food.
29% of Canadians surveyed believe farmers are good stewards of the environment.
$2.5 B
Total operating expenses for Canadian greenhouse growers (2016).
She’s told us time and again—she loves bicolor blooms! We’re delivering them on new varieties growers will love to produce. An Osteospermum whose flowers are always open for business, even on cloudy days. A restrained Thunbergia with an extended shelf life. A prolific Superbena that shrugs off mildew with ease. Genuine Proven Winners, every one.
BRIGHT LIGHTS ® Double Moonglow Osteospermum
Tangerine Slice A-PEEL ® Thunbergia
SUPERBENA ® Stormburst Verbena
Campfire® Fireburst Improved Bidens
Responding to the needs of growers, Proven Winners is replacing the original Campfire Fireburst Bidens this year with a more restrained, well-branched selection that works better in combination containers and hanging baskets. This vigorous plant thrives in heat and drought conditions where other flowers might need extra care, and its deep orange and yellow bicolour blooms keep right on coming from spring into fall. Dimensions are 1218” in height. Full sun. provenwinners.com
‘Green Twister’ Echinacea
‘Green Twister,’ from Jelitto, is a unique and colourful seed selection. This lively green coneflower will show natural variation in the colour and size of the green edge. A few flowers are light green but some are almost yellow-edged each with an increasing carmine-red centre.
Lantana Bloomify
“Bloomify will not multiply!” The first certified sterile lantana series on the market was bred through the University of Florida and meets the needs of hot and humid locations. New Bloomify does not set seed, so it won’t go out of flower in the heat of summer. The series features better branching than the competition for a better appearance at retail. There are two colours for 2018 sales: Red and Rose. Gardeners will enjoy its mounded ball-shaped habit. www.ballfloraplant.com
Petunia ‘Surfinia Trailing Red’
The petals are arranged around a large cone and there is very often a higher petal count. Flowering stems are shorter in the first year but normal size (around 100 cm/40”) in the second year. Many of these stems are a dark burgundy colour. www. jelitto.com
Rev up your reds with the new ‘Surfinia Trailing Red’ petunia from Suntory Flowers. Compared to popular ‘Surfinia Deep Red,’ plants are fuller and more vigorous as a premium trailer well-suited to hanging baskets. Flowers are larger with a brighter colour. This essential red will be perfect in patriotic combinations. Surfinia petunias are known worldwide for outstand ing garden performance. www.suntorycollection.com
Wave Plug & Play™ Combos
Bred for extra-large flowers, increased density of foliage, and earlier flowering, ‘XXL Tabasco’ joins the esteemed XXL Dahlia series from Dümmen Orange. After winning the prestigious Les Exceptionelles® award this year, these jumbo dahlias are now the undisputed top-choice for garden performance and retail positioning. Launched in 2006, Les Exceptionnelles is an
independent testing program of new flower cultivars in Quebec. Candidates are judged for natural superiority in the garden by consumers through public voting at the trial garden and a panel of horticulture professionals. Les Exceptionnelles are chosen for their beauty, performance, and easy care, as well as their insect and disease resistance. na.dummenorange.com
What’s better than one Wave® Petunia? Mix ’em to the max and serve up grab-n-go gardens that give today’s consumer plenty of time to enjoy life. Wave Plug & Play Combos feature on-trend colours that are virtually care-free. Fill your customers’ planters with easy spreading colour all season. Rev up your mix program with Wave’s proven-to-perform, proven-to-sell combos from seed. They’ll hold their own against any vegetative combination. www.panamseed.com/ PlugandPlay
For more New Varieties, visit the “Marketplace” section at greenhousecanada.com. We’re always looking for New Varieties (75 to 100 words with a high resolution photo) from flower and vegetable breeders; please send to greenhouse@annexweb.com.
Dahlia XXL Tabasco
BUSINESS ISSUES
www.360energy.net | info@360energy.net
Lighting and Energy Costs
Knowing how electricity impacts energy costs helps you optimize your greenhouse lighting.
Lights are one of the most important aspects of a greenhouse energy mix. Lighting extends the growing season to overcome seasonal changes that limit production and revenue. Lighting must be managed carefully to ensure the benefits are not offset by increased power costs.
Whether you already have lights or are considering installing them, you need to understand how the electricity requirements impact your budget. The best way to do this is with an energy plan that will help you:
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Doef’s Greenhouses (Lacombe, Alberta) has achieved significant energy savings through lighting strategies
• Understand your rates, usage patterns and total costs.
• Develop strategies to minimize costs.
Understand Your Rates: Understand your electricity rates, and how changes to your lighting technology or lighting acreage will change your rate class. Rates in most jurisdictions have two components:
• Usage-based commodity costs (on a $/kWh basis).
• Demand-based distribution and transmission costs (on a $/kW or $/kVa basis).
How these components are applied vary between regions. In Alberta and British Columbia, an increase in demand in any one month will pull demand-based costs higher throughout the year. In Ontario, demand costs only increase in the lighting months.
Ontario also has Global Adjustment, which is the bulk of expense for most growers. It can be charged in two different ways. Class B customers
(those whose yearly peak demand averages less than 500 kW or those who chose not to opt out of the class) have global adjustment billed based on a monthly rate per kWh. Class A customers (those above 500 kW who choose to opt out of Class B) have global adjustment billed based on a fixed percentage, determined by the site’s usage during the five peak hours of the previous year. By strategically modifying how you use lighting, you can influence your total costs. Class A and Class B customers may take different strategies.
Understand Your Energy Usage: The next step is to look at your interval data – the load profile illustration of your hour by hour usage. With an actual load profile (from historic use) or projected (from schedules for new lighting), you can compare your use against hourly rates and estimate what power costs when you are using it most. This helps you more accurately forecast monthly peak demand, usage and costs.
Interval data can flag potential changes in the effectiveness of your lights. Year-over-year comparisons may show declines in peak lighting load, providing an indication of (e.g.) outages that can be proactively addressed through maintenance.
Develop Strategies to Save: Doef’s Greenhouses in Alberta used their knowledge of usage and rates to reduce their annual demand-related costs by six per cent. They delayed the start of their lighting season by two weeks, which avoided incurring charges during an additional billing period. They saved a further five per cent with minor changes to crop rotation and lighting schedules. The changes had little impact on production, but significantly reduced their demand costs. In a different example, a greenhouse grower in Ontario asked their utility to extend their billing period by one week; this enabled an extra seven days of lighting while avoiding charges from higher demand.
For Class A customers in Ontario, tweaking operations to avoid the five peak hours can significantly reduce costs; mistakenly using full lighting load during the peaks can significantly increase costs. Planning ahead is critical.
A solid understanding of how electricity impacts your energy costs helps you plan to optimize your greenhouse lighting; minimizing costs while maintaining or increasing yield.
This article was supplied by 360 Energy, one of North America’s leading energy services firms.
TECHNICAL ISSUES
Beating the Beast
The pepper weevil can develop a large population (300-600) from fertile egg to adult within two weeks.
The pepper weevil has become a bigger nightmare for pepper growers in Leamington area. The swarming of pepper weevil in the Leamington area might be a result of the milder winters and more year-round greenhouse production, inter-planting schemes and lack of attention on greenhouse cleaning procedures that enhance the survivorship of pepper weevil. Ignoring just one adult weevil is a reason to take out an entire crop. That’s because due to high temperatures in the greenhouse, the
weevil can develop a large population (300-600) from fertile egg to adult within two weeks. As a result, the fruits or buds fail to develop a mature harvest and abort even at the older fruit stage.
Flowering buds and young fruits are the favourite parts of pepper crops in which the larvae develop. Adults can survive on stems and leaves in the absence of fruits and are ready to attack as the buds appear.
The female creates an egg cavity with her mouth parts before depositing eggs and will seal the puncture containing the egg with a light brown liquid that hardens and darkens over time. The punctures they create in peppers open penetration holes for different kinds of fungi.
Use of Entomopathogenic fungi like Beauveria bassiana, Fusarium temperatum, Fusarium verticilliodes, Metarhizium anisopliae etc., is one of the important control methods of insects including pepper weevil. Scientific reports show that both Beauveria and Fusarium have been used to control different kinds of weevils, including pepper weevil. But all these success stories are accomplished under controlled
laboratory conditions, where the environment is ideal for the virulence of the fungi. The efficiency of these entomopathogenic fungi was found very low when applied under field conditions.
Following the trend and severity of the problem particularly in Leamington area GrowLiv Ltd started a research project in 2016 to beat the beast of pepper weevil. It is trying to solve the question of why entomopathogenic fungi are not working under field or greenhouse conditions.
After an extensive literature search and experimentation, the company is now able to control/manage the pepper weevil in four commercial greenhouses. The entomopathogenic fungi was found colonizing inside pepper fruit only when the pepper weevil larva moves into the fruit cavity. There was no fungus inside the fruit if the larva was killed by fungus at very early stage right inside the surface cavity on pepper fruit where the weevil deposited its egg. The procedures developed are providing a suitable environment to entomopathogenic fungi to grow faster and persist longer on the crop. This method has been observed highly fetal for larvae, pupae and adults of pepper weevil both inside and outside of the pepper fruit.
The MycoLiv system is a comprehensive approach towards a successful microbial control of pepper weevil. A suitable myco-insecticide and the biostimulant are key components of the system. The biostimulant is helping beneficial fungi to survive longer on the crop foliage, increases its virulence and colony forming ability. In general it improves plant health as well as the fruit quality and encourages growth of other beneficial microbes in the crop environment. The right concentration of the both components is crucial part of the program.
It is suggesting its own spray design. It uses high volume spraying (min. 200 L spray volume per acre), focusing mainly on the top one-third of pepper plant. Teejet (AI80015) nozzles are delivering the right volume and droplet size when operated at 15 bar pressure. Morphology of crop canopy, orientation of spray nozzles and the speed of sprayer determines the right amount of spray volume for proper coverage of target area. Crop work such as pruning helps lot for better penetration of the spray. A regular treatment of new growths on the pepper plant, right with the start of crop, might be helpful in controlling pest complex of greenhouse peppers including pepper weevil.
ABOVE
A dead adult pepper weevil collected from a greenhouse.
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HPS or LEDs (or both): which system will work best for you?
The following are highlights of a presentation made during a research conference hosted by Flowers Canada Ontario earlier this year.
LED technology is increasingly being used in sole-source lighting (SSL) for all types of horticultural applications – both in greenhouses and indoor facilities.
There are many compelling reasons why growers are making the switch to LED technology, including:
Energy savings – LEDs use up to 40 per cent less energy than traditional HPS systems to deliver the same light levels.
Optical design freedom – LED optics offer exceptional design flexibility in terms of light level, colour spectrum and distribution pattern.
Spectral tuning – LED fixtures offer multiple colour spectral variations – each specifically designed to elicit the desired plant response – including leaf size and stem elongation, chlorophyll concentration, pigment concentration, branching and early/late flowering. Plant response times are also often faster with LEDs.
Heat management – LED fixtures produce less heat and can be placed closer to plants, enabling higher light intensities without excessive heat. Reduced heat also translates into reduced water consumption.
Long life, low maintenance –LEDs last much longer than HPS lamps, and require far less maintenance.
From a horticultural perspective, the spectral “tunability” is probably the most unique benefit, so let’s take a closer look at what that means.
The chart Fig. 1 shows a spectral comparison of an HPS lamp vs. 100 per cent red; 85 per cent red/15 per cent blue; and 70 per cent red/30 per cent blue LEDs.
As you can see, the HPS lamp delivers the widest range of wavelengths; however, plants and humans perceive light very differently. The human eye responds most strongly to light in the green/yellow part of the spectrum, whereas plants respond most strongly to the PAR region (blue and red wavelengths) for photoperiodic growth responses and germination control.
Given that much of the light emitted by HPS lamps is not usable to plants – the HPS spectrum is far less efficient than with LEDs where the spectral output can be targeted to only those wavelengths that are useful to the plant.
Photosynthesis, flowering, climate response and photomorphogenesis are all affected by the intensity, duration, distribution and spectral quality of light. Since plants respond most strongly to the red and blue wavelengths, with LED-based sole-source lighting (SSL), we can
Many growers are currently opting to install hybrid lighting systems, i.e. a mix of LED and traditional technologies –allowing them the benefits of both technologies.
BY STEVEN SZEWCZYK
tune the lighting to focus on what the plant uses most.
So one of the major challenges in designing LED fixtures for horticultural applications is developing optimum colour efficiencies or “colour recipes” to deliver PAR photons as efficiently as possible and essentially allow growers to “tune” their lighting to the optimal wavelengths for each stage of growth.
For example, if a grower wanted to encourage more compact growth, with sturdier leaves, they would use a higher component of blue light; however, if the intent is to encourage flowering, the grower would use less blue light and more red light. Similarly, the pigment of the leaves can be manipulated by using specific wavelengths
So all of this is very exciting, but we cannot dismiss the fact that there are still some obstacles to be overcome before we see large-scale adoption of LED lighting in horticulture.
In the past, there was no alternative to traditional light sources like HPS. So although we could measure light intensity (quantity), we were not able to measure the effects of specific spectral colour compositions. However, with the development of LEDs, this is now possible.
We are still very much in the research phase as far as light spectrum compositions and their effect on plant growth, fruit yield and quality goes. We are still discovering which crops respond well to LED lighting, and to specific spectral recipes. Even certain varietals can react differently to a particular spectral composition.
Probably the most significant roadblock for widespread adoption of LED lighting is the high cost of ownership.
A good way to get a true comparison between the cost of LED vs. traditional lighting is to look at the cost per µmol delivered, as the outputs from one manufacturer to another can differ. Below is an example to demonstrate:
• 1000w HPS DE Fixture w/ 2100 µmol output at $550* = $0.26/µmol.
• 215w LED Top Light w/ 550 µmol output at $420* = $1.31/µmol.
• 320w LED Top Light w/ 860 µmol output at $950* = $1.10/µmol.
* Pricing is ballpark/MSRP.
An incremental cost of four to five times that of HPS means you have to look at many factors to determine if the ROI on converting to LED makes sense.
Fig 1.
Excellent results for Winter & Early Spring Plantings
Winmar RZ F1
Cca/Ccu Px (ex Sf)
Cervello
RZ F1
Tomatoes
Endeavour RZ F1 - Large TOV
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Prodezo RZ F1- Large
TOV
ToMV:0-2/Ff:A-E/Fol:0/For/Va:0/Vd:0 On (ex Ol)
Kivu RZ F1 -
Beef
ToMV:0-2/Ff:A-E/Fol:0,1/For/Va:0/Vd:0 On (ex Ol)
For USA: Rijk Zwaan USA Inc. | Phone (832) 455 3000
Greenhouse Crop Specialist Tomato Rijk Zwaan Export B.V. | Marleen van der Torre | Phone (226) 344 6670
Growers should consider not only the initial capital expenditure costs of the luminaires themselves, but also the incremental costs associated with a transition to LED lighting.
converting to LED technology is a BIG investment, so make sure you do your homework in advance.
Use the “LOGIC” checklist to bear in mind when considering an LED lighting
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fixtures that are engineered specifically for horticultural applications. Factors to consider include light intensity (µmol/m2/s ), fixture efficiency (µmol/J); light distribution and spectral recipes. Look out for exaggerated claims. A reputable manufacturer will offer a complete system warranty with a rated lifetime of 50,000+ hours and a guaranteed photon flux maintenance under typical operating in a
Return on investment for LED lighting is different
Payback calculations for LED lighting are only useful when they apply specifically to your situation. Look for a manufacturer who will provide a custom light plan that considers all the factors specific
Use the “LOGIC” checklist to bear in mind when considering an LED lighting system.
A good LED lighting system is a big investment, so do your homework. Ensure you are considering all factors when calculating your cost of ownership. The cheapest price may turn out to be an
What does the future hold for LED technology in horticultural applications?
As we learn more about LEDs in relation to horticulture, we will undoubtedly see increasing general adoption as researchers, manufacturers and growers become
And much like the general lighting industry adopted a set of quality standards and benchmarks like the Lighting Facts program, so too will we start to see set standards emerge in the horticultural industry.
For now, many growers are opting to install hybrid lighting systems, i.e. a mix of LED and traditional technologies – allowing them the benefits of both technologies.
Steven Szewczyk is the regional sales manager for Eastern Canada and the Northeast U.S. for P.L. Light Systems/Agrilight Inc.
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ARE PESTICIDES compatible with biocontrol?
When using biocontrol, it is important to understand the role that pesticides play in supporting the program.
BY GRAEME MURPHY, DR. ROSE BUITENHUIS, DR. MICHAEL BROWNBRIDGE
This is the last part in a six-part series of articles on thrips (and other pests) integrated pest management, where we provide practical application tips and tricks, information on new technologies and how it all fits within an overall IPM program. Each article is accompanied by a short video demonstrating a technique or principle. The content of this series is based on research performed at Vineland Research and Innovation Centre and is supplemented with ‘information from the field’, contributed by colleagues using biocontrol strategies in greenhouse production. For more information on specific biocontrol agents or IPM in general, see www.greenhouseIPM.org.
Imagine a pesticide that is effective against a wide range of pests, resistance doesn’t develop, is safe in terms of human health and the environment, and is completely compatible with all biocontrol agents. Clearly, that’s a pipe dream but what if we lower our expectations a little; how about a pesticide that
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controls one or two pests and is compatible with a few biocontrol agents?
Definitely more realistic, but it still leaves the question: what is pesticide compatibility anyway, and how can we make use of pesticides to support biological control?
As Suzanne Wainwright-Evans (aka “The Bug Lady”) put it during
Drs. Michael Brownbridge and Rose Buitenhuis, of Vineland.
the recent IOBC-Greenhouse IPM meeting: “Many growers are moving to integrate biological control agents into their pest management programs, but are finding that it is not as simple as just replacing a pesticide application with a release of insects or mites. Rather, a holistic approach needs to be taken to successfully move to a bioprogram.”
In short, many factors need to be considered when integrating pesticides with biologicals.
Ideally, a preventive biocontrol program will proceed exactly according to plan, providing excellent control of all pests on a long-term basis. Unfortunately, pest/natural enemy populations often get out of balance for a variety of reasons:
• New, or secondary pests become established.
• An influx of pests from outside overwhelms the established biocontrol program. We saw such an event in many Ontario greenhouses in late June/early July of 2016, when huge incursions of western flower thrips occurred across the Niagara region.
• Pesticide residues on incoming plant material may adversely affect the biocontrol agents in the greenhouse.
In any or all of these situations, judicious use of pesticides may be needed.
When talking about the implementation of biocontrol in greenhouses, the issue of pesticide compatibility is always a major part of the discussion. All the major biocontrol producers have side-effects lists on their websites or available as downloadable apps that provide some indication of the acute toxicity of pesticides against various natural enemies. These lists rate the mortality of a specific natural enemy when exposed to a pesticide, ranging from “1” (0-25 per cent mortality) to “4” (75-100 per cent mortality), and state the length of time in days or weeks that residues will persist and be active.
You will note that compatibility does not mean safe. Even a pesticide assigned a “1” on the above scale can still kill up to 25 per cent of natural enemies. And if it is sprayed every week….
Information on side-effects is obviously very useful and growers need to have an understanding of the potential impact that pesticides can have (should they need them) on their biocontrol programs. However, there is more to pesticide effects than their acute toxicity. Whether or not a pesticide kills a biocontrol agent is not always so black and white. There are also sub-lethal effects, i.e., those that don’t cause death but may reduce the effectiveness of the biocontrol agent.
For example, there may be reductions in the searching ability of the predator or parasite, general movement, egg laying (number of eggs, egg survival and hatch), lifespan of the adult, fitness of the males and/or females in mating. The list is long and it is expensive to carry out all the trials needed to produce this type of information. For the most part, we get by on the bare minimum (how many adults/larvae are killed and how long do the residues remain active), but it is important to keep sub-lethal effects in mind as part of pesticide compatibility
There is one other thing to bear in mind concerning sideeffects. For the most part there is general agreement among the side-effects lists of all the major biocontrol producers. However, companies carry out their own research into side-effects and update their lists as new information becomes available. For this reason, the side-effects listed by different companies do not always agree, and there may be disparities in the assigned toxicity rating or the period of residual impact. Whenever there is a discrepancy, use the more conservative value, i.e., the highest toxicity
rating and the longest residual period. Treat side-effects lists as guidelines rather than as permission to spray.
When considering pesticides that can support a biocontrol program, we can think of them in terms of how they should or should not be used:
Those that should never be used – ever! These are often highly toxic to natural enemies with a persistence of 2-3 months, sometimes more. Many of these are older pesticides, e.g., pyrethroids such as permethrin (Pounce) and deltamethrin (Decis), and many organophosphates such as malathion, chlorpyrifos (Dursban/Lorsban) and acephate (Orthene).
Can sometimes be used – maybe. These include pesticides that are toxic to a broad spectrum of biocontrol agents, but have a shorter residual period than those described above. They can be used to clean up a greenhouse (especially while effects of more persistent products that have been applied still exist) or in spot sprays (but be careful with spot sprays; they still have the potential to seriously disrupt biocontrol programs). Examples include abamectin (Avid), which is highly toxic (4 on the side-effects scale) to a
wide range of biocontrol agents and has a residual period of two to three weeks. Some products may be much more toxic or have a much longer residual period against predatory mites than against insect biocontrol agents. Additionally, some of these products may be safe when applied as a drench, but harmful as a spray. For example, imidacloprid (Intercept) is generally safe to use as a drench in a predatory mite-based biocontrol program, but not if used as a spray. Yet, no matter how you apply it, it will be very disruptive to parasitic wasps such as Encarsia or Diglyphus. But imidacloprid’s future is uncertain at this time…
Toxic products with an important role in IPM. Although toxic to many biocontrol agents, certain products have virtually no residual effect and biocontrol agents can be re-introduced almost immediately or within a few days. Examples are soap, mineral oil, DDVP. DDVP is very old chemistry (an organophosphate) and is highly toxic to almost everything in the greenhouse (including people), but it is also very volatile, vaporizing quickly and disappearing from the greenhouse in one to two days. As such, it is widely used as
a cleanup product prior to introducing biocontrol agents because the impact on them is so short-lived. The registration of DDVP is currently being re-evaluated by the PMRA in Canada.
Somewhat compatible. These are pesticides that have varying levels of impact on biocontrol agents and generally short persistence:
• Insect growth regulators such as cyromazine (Citation), diflubenzuron (Dimilin) and kinoprene (Enstar II) fall within this group.
• Miticides like fenbutatin oxide (Vendex), bifenazate (Floramite), acequinocyl (Shuttle) are also included.
• Some of the newer chemistries that fall within this category provide growers with a wider choice of options. For example, flonicamid (Beleaf) appears to be safe for most biocontrol agents and the diamide insecticides such as chlorantraniliprole (Coragen, Acelepryn) and cyantraniliprole (Exirel) likewise seem to be broadly compatible. However, even with products that
Graham Bolton FCC Senior Relationship Manager
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initially seem to have a good fit with biocontrol programs, some biocontrol agents may still be affected and many have not yet been extensively tested.
• Biopesticides can also fall into this group. These include microbial bioinsecticides such as BotaniGard and Met 52, and various biofungi cides. The use of biopesticides in IPM has been previously discussed in this series. In general, they are safer than most conventional
pesticides but they can still have a detrimental effect on biocontrol agents. For example, Orius can be
flip side to this is that the action of fungal bioinsecticides like BotaniGard and Met 52 can be adversely affected by fungicides used for disease management.
What about pesticides other than Various fungicides and plant growth regulators (PGRs) also affect biocontrol agents. While materials in both groups are commonly less toxic to biocontrol agents than insecticides or miticides, there are exceptions. Thiophanate-methyl (Senator) is highly toxic to some biocontrol agents with a residual period of over two weeks. To reinforce an earlier comment, be careful; one Side-Effects List shows this product has Level 4 toxicity against Encarsia, while another shows it as Level 1. As for PGRs, there is very little information in the Side-Effects Lists. However, research in North Carolina in 2013 showed significant sub-lethal side effects of some PGRs . So, do not assume that
Those that are completely compatible with all biocontrol agents. Are there any?
One final point needs to be emphasized. Compatibility of pest control products needs to be considered within the context of the entire crop management program. We cannot focus just on thrips or whiteflies – or whatever the primary pest of concern may be. For example, the use of imidacloprid (Intercept) can lead to an increase in spider mite populations. The products that might be considered to control a secondary outbreak of a pest such as tarnished plant bug, may have impacts beyond just that target pest. Similarly, many miticides also have insecticidal activity, so there may be unintended consequences for beneficial insects. Conversely, insecticides may be harmful to predatory mites. This may seem counter-intuitive but these assumptions are often made, and failure to check the compatibility of pesticides prior to their use have resulted in program failures.
To summarize, when using biocontrol, it is important to understand the role that pesticides play in supporting the program. However, equally important is to know their limitations, and to appreciate that our knowledge is far from complete.
Graeme Murphy (graeme.murphy307@ gmail.com) is a greenhouse IPM specialist, bioLogical control solutions. Drs. Rose Buitenhuis (Rose.Buitenhuis@vinelandresearch.com) and Michael Brownbridge (Michael.Brownbridge@ vinelandresearch.com) are scientists at the Vineland Research and Innovation Centre.
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Ontario research update: LED lighting systems in floriculture
Every operation has different requirements; as with any technology, there are many considerations to take into account before taking the plunge.
BY DR. CHEVONNE CARLOW
There’s been a lot of talk about light-emitting diode fixtures (LEDs) in the greenhouse industry over the last few years. They are often marketed as the solution to our electricity woes with the added benefit of spectrum control for specific crops.
However, as with any technology, there are many considerations to take into account before taking the plunge.
The purpose of a greenhouse is, in part, to use the sun as much as possible.
For Canadian greenhouses, this is more challenging through the winter months when there often isn’t enough light for optimal production. As a result, efficient lighting to supplement or adapt light in the greenhouse for improved production under low light is of interest to many year-round growers.
However, when it comes down to comparing LEDs to standard greenhouse lighting practices,
we are often left with many questions.
High-pressure sodium (HPS) lights are well known to us. They provide a full spectrum of light that can be used by the plant (PAR light, or Photosynthetically Active Radiation), along with a heat byproduct, which you may be happy to reap benefits from through the cold winter months.
However, with the cost of electricity set to jump in the next few years, this wasted energy isn’t the most efficient way to heat or light a greenhouse.
On the other side, much of what we know about LEDs is still evolving, or unknown. We know that they waste less heat and are more energy efficient compared to HPS lights.
Not all LED fixtures are created equal, and depending on the light intensity and spread, you may need more fixtures in the greenhouse to achieve a similar light level as compared to HPS fixtures.
Compared to HPS, LEDs remain a larger upfront
ABOVE
Figure 2. Plants accumulated more mass under HPS lighting than LED lighting, even though this wasn’t always apparent visually or in spread measurements.
investment, but the energy savings may help to pay that upfront cost back in the end. The benefits tuning the light spectrum to produce the same high quality crops in addition to value added traits such as different colouring, habits or flavour profiles is certainly exciting, and is the focus of several research projects.
Greenhouse lighting research projects in Ontario continue to look at both cut and potted flower crops. The studies highlighted in this article have focused on the comparison of HPS to LED (typically 70-80 per cent red to 20-30 per cent blue ratios) light.
CUT FLOWERS: On the cut flower side, gerbera have been shown to be more consistently of market quality across harvest weeks under LED lights, but the harvest is slightly less than with HPS (Zheng, Llewellyn and Vinson; University of Guelph).
Ongoing work in lisianthus and chrysanthemum has shown that buds are initiated faster under HPS than LEDs of various spectrums, but this is probably more related to the extra heat given off by the HPS fixtures than the spectrum itself (Grodzinski, Leonardos and Ma; University of Guelph).
Potted crops: Work done at the Vineland station by OMAFRA and Flowers Canada Ontario with potted crops has found that different species are more sensitive to the difference between HPS and LED than others.
Our initial trials focused on the spring bedding plants verbena, calibrachoa and petunia
Consistent with the cut flower studies,
flowers grown under HPS lights accumulated more dry mass than those under LEDs (Figure 1).
In terms of plant spread (as measured by the height and width of the crop) and flowering time, the results indicate that the variety or species may have a large effect on how the plant behaves under different lighting (Figure 2).
Differences in size and flowering weren’t seen or weren’t significant in both calibrachoa and petunia. In this case it’s likely that the genetics, especially for the
compact calibrachoa variety, played a role in this response.
The verbena however was significantly larger and approximately one week earlier to flower under HPS lights. Considering a temperature difference of between 2-4 C at the leaf level between HPS and LED pots, this result isn’t surprising. However these results do emphasize the importance of trialing out species specific responses in your own greenhouse.
As with all research, answers to our most pressing questions lead to more
Petunia Verbena
ABOVE
Figure 3. Species specific responses show that the calibrachoa and petunia varieties used in this trial were similar in spread and flowering time under either LED or HPS lights. Verbena on the other hand, was larger and flowered one week earlier under HPS as compared to LED.
questions! For example, what’s the effect of LEDs on your IPM program; do your pests or biocontrol agents work differently under different light? Are specific spectrums more critical at certain stages of production like propagation than others like finishing? What’s the overall effect of LED light on the shelf life of potted flowers?
Major changes to production systems, such as switching from HPS to LED lights, often require us to adapt other production practices to optimize growth production. So, for example, a switch to LED might mean that you need to
irrigate less frequently, or account for an extra week in your production schedules. Remember, these details all needed to be figured out for HPS lights at one time too!
The takeaway: So, in the end, how do you know if LED lights are right for you? This is the ultimate question, and it can only be answered by taking stock of your own operation and asking some more questions. This will be an ongoing process of course, but here are a few to get you started:
• Know your operation – Do you need light?
• Know what you want – What is
the purpose of the light?
• Know the economics – Is this a smart long term decision?
• Trial it out – Participate in getting meaningful results for you!
Dr. Chevonne Carlow is the OMAFRA greenhouse floriculture specialist.
• Chevonne.Carlow@ontario.ca.
FOR MORE ON GREENHOUSE LIGHTING, VISIT THE “STRUCTURES AND EQUIPMENT” SECTION AT GREENHOUSECANADA.COM.
FOR SENDING IN YOUR NOMINATIONS!
Canada is full of young, skilled and knowledgeable people who are driving the greenhouse industry forward. From commercial growers and wholesalers to manufacturers, equipment suppliers and service providers, they are the best and brightest in our industry. Join us as we celebrate the future of horticulture in Canada.
Winners of the Top 10 Under 40 will be featured in the November issue of Greenhouse Canada and will be announced during “The Gathering” on October 4th at The Canadian Greenhouse Conference in Niagara Falls.
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THE PLANT’S perspective on supplemental lights
With more and more growers growing through the winter months, we wondered what effect the lights have on the crops. One ‘expert’ gave us the scoop.
Growing vegetable crops in winter in Canada is now an established practice in the sense that we know how many lights should be installed and how much light can be delivered to plants. Good information is available on a number of micromoles needed for leafy and fruiting crops and what is a good Daily Light Integral (DLI). With the arrival of LED lights we heard the term “top lights” and “inter-light.”
teacher trying to explain sunlight to the class.
BY DR. MOHYUDDIN MIRZA
I still see crop management problems during winter months and they are primarily related to us not thinking about the plants enough when lighting is applied.
Light spectrum: In plain language, whenever I think about sunlight, I think about a young boy – that is me – sitting on a jute rug on the dusty ground under a tree and a
After being convinced that we students were not going to remember that light consists of different spectra and wavelengths, he made us memorize VIBGOYR. It was a fancy word not found in the dictionary and we memorized it quickly. Then we memorized V for violet, I for indigo, B for blue, G for green, O for orange, Y for yellow and R for red. So that is it. This VIBGOYR is stuck with me. Then the teacher asked us why we were sitting under this tree. Our answer was that the tree provides shade and shelter from the sun. Now I understand better the role of green chlorophyll in plants.
Here are the corresponding wavelengths for the colours:
COLOUR Wavelength
VIOLET 380-450 nm
BLUE 450-495 nm
GREEN 495-570 nm
YELLOW 570-90 nm
ORANGE 590-620 nm
RED 620-750 nm
From a plant viewpoint, blue and red spectra are the two most important for photosynthesis and some other functions. The contribution of other spectra like green, UVa and UVb are slowly being investigated.
Here is an example of how plants react to blue light. (Blue Light 400-500 nm)
• Better penetration in leaf tissue.
• Stomatal regulation.
• Provide shorter internodes.
• Thicker and darker leaves.
• Increased root mass.
• Flower induction.
Red and far-red also have important functions. The bottom line is when growers use lights they should know the spectrum, the intensity in micromoles, and the DLI. The most important fact is that in a greenhouse the light is called “Supplemental.” And this is supplemental to natural light available.
Growers should know about joules as well. Most greenhouse computers will give readings in joules and watts. Joules trigger irrigation, while watts are used for turning the lights on and off and for screens.
The plant’s perspective when to turn the lights on: Once the supplemental lights are installed then growers have other perspectives in mind. Power is expensive and now with added costs like higher minimum wages, overtime payments and increased costs of labour and inputs, growers want to use lights when it costs less.
For example, growers prefer to turn lights on around 1 a.m. when the power rate is the lowest.
Here is the problem with this approach and this is not a “small” problem. Plants get totally confused and ask the
question, what are you doing?
Lights are turned on at 1 a.m. and Vapor Pressure Deficit (VPD) is very low. VPD is measured in millibars or grams of moisture per cubic metre of air. The VPD generally is around less than one gram, which means it is very humid and the plant is not transpiring. Screens are open to save heat.
What we are doing by turning the lights on is sending a signal to plants to open their stomata and start “working.” Yet the plant is saying, “OK, you are not doing
me any favours. I cannot start working because I cannot transpire. And if I cannot transpire, and you start irrigating my roots there will be more trouble for me and for you. For me it is pain in every cell. My roots are telling me that they have to get rid of water at 1 a.m. and the leaves are saying, sorry my stomata are not open!
WHAT ARE THE CONSEQUENCES
“My entire world goes haywire because my cells started bursting with the root pressure created by not understanding
my physiology. I am designed to take up water from roots loaded with all the nutrients and then I retain them in my cells and let the water go into the air.
“However, the VPD was very low at the time you decided to turn the lights on because the price of electricity was cheaper. Once my cells are burst, then my chronic enemy, the dreaded powdery mildew, is waiting there to come and those good foods I made for a different purpose are now used by my enemy.
“Even the fruit I made for you is no good because it started turning yellow and consumers don’t like it. My leaves can become loaded with powdery mildew and Cucumber Green Mottle Mosaic Virus (CGMMV) can attack me. In case if you want to know the name of this disease of cell bursting, it is called edema. This is the same thing when your feet are swollen and kidneys are not removing water from your body. This is how my tomato leaves looked like with edema in winter (photo at right).
“So, I would humbly request you don’t turn the lights on until the VPD is at least three grams/m3 of air. I know your arguments as well. Oh, it is very cold,
you say, and you have to keep my vents closed and use the energy screen. You can always start giving me light in different ways as well. You can start giving me supplemental light an hour before sunset and continue for few hours or start before sunrise.”
Winter is coming and by early
October growers start using supplemental lights. Please pay attention to the needs of the plants you are growing. Read the plants carefully and make adjustments accordingly.
Dr. Mohyuddin Mirza is an industry consultant, drmirzaconsultants@gmail.com.
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ABOVE
Tomato with edema.
THE LATEST on lighting
A spotlight on some of the latest research at Harrow, University of Guelph and Wageningen University
BY TREENA HEIN
Lighting research is very exciting these days, with manipulation of LED placement and wavelength both possible. We checked with three leading greenhouse lighting researchers to hear about their newest studies – some ongoing and some recently completed, some new and some building on previous studies.
One of the projects of Dr. Youbin Zheng, associate professor in the University of Guelph’s School of Environmental Sciences, has the goal of determining the best light spectral combinations and intensities for indoor/warehouse and greenhouse microgreen production. This study, supported by the National Research Council (NSERC) and Greenbelt Microgreens, involves investigation of both yield and quality (for example, nutritional value and post-harvest shelf life).
Zheng is also developing a feedback control system to manage greenhouse lighting in order to save energy and maximize crop production. The work is supported by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and Heliospectra.
“Our recent trial compared the use of a conventional HPS control strategy with real-time feedback-controlled LEDs (which are dimmable) for the production of cut gerbera in Ontario during the normal supplemental lighting season of November to March,” notes Zheng.
“Results showed that the LED treatment had the same or better crop growth, harvest and
Lighting is essential with year-round vegetable production in Canada.
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quality metrics compared with HPS, while also delivering 15 per cent less supplemental light overall to the crop throughout the season.”
DYNAMICALLY CONTROLLED LEDS
Zheng says these results provide a compelling argument for the use of dynamically controlled LEDs as a supplemental light source for greenhouse production in the darker months in northern latitudes.
Another of his studies involves using LEDs to control plant height. Bedding plant growers often produce hanging baskets above the main lower crop level (bench or floor) in the same greenhouse to maximize use of production space, he notes. This practice reportedly can result in stretched plants at lower crop level, commonly considered a result of a combination of high-density plantings, competition for available light and changes in spectral composition from passing through an upper canopy.
“Our group has been investigating how to use different light spectral combinations and timing of light treatment on the morphological changes of several bedding plant species (e.g., petunia, marigold, geranium),” he explains, “to investigate whether we can control bedding plant height and flowering without using chemicals.”
CUT FLOWER PROJECTS
Supported by the International Cut Flowers Growers Association and Lumigrow, Zheng has also recently investigated the use of LEDs for producing cut flowers during the darker months in
ABOVE
Lighting trials with peppers at Harrow Research and Development Centre.
Ontario over three growing seasons.
“The first year we compared HPS and LED supplemental lighting treatments (at the same crop-level intensity and photoperiod) to produce three cultivars of cut gerbera,” he says. “The LED treatment provided similar or better production, harvest quality and postharvest shelf-life indices compared with HPS treatment.”
In the second year, a single cultivar of cut snapdragons was produced using four different canopy-level supplemental LED intensities, and in the third year, two cultivars of cut gerbera (one starting in plug-stage and the other already in flower) were grown under five different supplemental light treatments.
The results of both of these trials can be used to help growers determine the optimum lighting setup for their specific production systems.
Zheng and his colleagues are also actively investigating the responses of different plant species to different LED light spectra and spectral combinations to unlock some of the mechanisms involved. This will guide the development of different lighting recipes for specific functions such as increasing or decreasing height, branching, increasing biomass production, promoting flowering and increasing certain nutrients in edible crops.
YEAR-ROUND VEGETABLE CROPS
One research project led by Dr. Xiuming Hao is focussed on economical year-round vegetable production.
“In Ontario and most places in Canada, we are short on light from October to March,” says Hao, who is based at the Agriculture and Agri-Food Canada (AAFC) centre in Harrow, Ontario. “Growers want to plant tomatoes, cucumbers and peppers in September or October in order to harvest around Christmastime to get the best price. Supplemental lights can achieve this, but
variety, nutrition and climate control are important factors affecting plant growth and fruit production and need to be adjusted.”
This and Hao’s other projects are being funded by AAFC Peer Review Program, AAFC’s AgriInnovation Program and the Ontario Greenhouse Vegetable Growers.
Hao and his colleagues have already found that lower intensity over a longer duration costs less in capital expenses with fewer light fixtures required per unit area. However, crops exposed to longer periods of light can be pushed beyond their limits; the yellow spots of chlorosis will appear on leaves and there can be little yield increase.
“We’ve developed a solution where we lower the temperature right after the supplemental lighting was shut-off during the darkness so the crop has a better rest and is not so stressed by the increased duration of light,” Hao explains. “A temperature of 13.5 to 14 C is suitable as a minimum for tomatoes, 13 C for cucumbers and 15.5 to 16 C for peppers, to maintain quality. There are also small differences among varieties.”
Not only does the temperature drop give the crop a good rest, but while it occurs, leaves cool faster (due to their large surface area in relation to volume) than the fruit (larger volume). This causes the plant to focus on growing the fruit, resulting in faster fruit growth and increased yields.
Hao notes that it takes one to two hours to lower the temperature depending on the temperature outside, and 30 minutes to one hour to bring it back up.
“You only want the temperature to stay lowered for about a half-hour to one hour,” he says, “just giving the plants a little
shock.” In addition to ensuring better yield, lowering the temperature also saves growers money on heating.
FAR-RED LED LIGHTING
Hao is also studying far-red LED light, wavelengths in the 720 to 750 nm range out of the visible range of humans. Applying far-red light at the top of plants is interpreted by them to mean they are being shaded, and in response stems and leaves stretch to reach for more light.
“Most greenhouses currently use HPS lights that produce lots of heat and the plants are very compact,” Hao notes. “However, with bushy plants, the light is being blocked by leaves and not utilized efficiently by the plant. With far-red LED, you get a longer plant that can intercept and absorb more light, and can achieve higher yields in the early production period in tomatoes and sweet peppers. Later on, the canopy is thicker and there is no effect.”
Cucumbers do not show any effect, he explains, because they grow very quickly in comparison.
Hao is also in the first year of a three-year comprehensive study looking at the use of LED lighting to improve crop growth, fruit yield, quality (including anti-oxidants) and pest control efficiency on tomatoes, peppers and cucumbers. Team members include Dr. Rose Labbé at Harrow (biocontrols and pests); Dr. Aiming Wong of AAFC London Research Centre (how LEDs might help greenhouse vegetable crops increase tolerance or resistance to virus disease); Dr. Rong Cao of AAFC’s Guelph Research Centre (antioxidant levels in fruit); and University of Guelph scientist Dr. Bernie Grodzinski (how LEDs
can speed up the movement of starch from the leaves to the fruit for increased yield).
“Red light is good for growth but blue light and UV-A light is better for fruit quality,” Hao explains. “With LED lighting, you can change the wavelengths at various heights. With red light and far-red light at the top and blue light in the middle, we try to increase both fruit yield, and quality and antioxidants at the same time.”
For fruiting greenhouse vegetables such as tomatoes, the translocation or movement of photo-assimilate (sugar etc.) from leaves to fruit is very important. Jason Lanoue (a PhD student at the University of Guelph under the supervision of Grodzinski and Hao) is studying various spectra of LED and developing LED light recipe to promote the translocation of photo-assimilate from leaves to fruit for increasing fruit yield.
WAGENINGEN PROJECTS
At Wageningen University in the Netherlands, Dr. Anja Dieleman has been working on LED greenhouse lighting for five years.
“Several years ago, one of my colleagues,
Tom Dueck did multiple trials in which he compared LEDs with HPS and hybrid systems (HPS+LED inter-canopy lighting; LED + LED inter-canopy lighting) in tomatoes,” she notes, “with the result that these systems were comparable in crop production.”
“Adding far-red light in the cultivation of tomatoes, with striking results.”
During the last few years, within the framework of the EU HI-LED Project (www. Hi-led.eu), Dieleman and colleague Esther Meinen have been studying the effects of light colours on young pepper and tomato plants. They found two hours of green light at various times of day all provided taller plants with more open canopy, with light better able to penetrate the crop. These results show that green light provides plant ‘stretching’ effects similar to far red light. The effect
of other colours was similar to white light.
Dieleman and her colleagues have also developed lighting recipes in which plants received a few hours of blue or green light in the morning followed by red light during the rest of the day (in addition to normal solar greenhouse light). Several hours of blue light at the start of the day led to an eight per cent increase in tomato production.
“In the last few years we have been working on adding far-red light in the cultivation of tomatoes, with striking results,” Dieleman adds. “Adding far-red light favours assimilate partitioning to the fruits, at the expense of the leaves, which led to a five to 20 per cent increase in tomato fruit production depending on the variety.”
Dieleman and her colleagues are also still working on the design of low carbon footprint production systems for tomato production, based on LED lighting and varieties that suit this lighting system best.
Treena Hein is a freelance writer in Ontario and a frequent contributor to Greenhouse Canada.
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The e cke Poinse TT ia Manual
Who better to help you grow your poinsettia crops than the world’s leader?
The Paul Ecke Ranch, the world’s largest poinsettia breeder, shares its expertise on how to grow and market the number one Christmas flower.
This manual provides everything a grower needs to know about producing and selling this pervasive crop of red, pink, yellow, purple, speckled, and marbled flowers.
Using its vast experience, The Paul Ecke Ranch provides a great guide to selecting cultivars and growing high-quality crops. After giving a brief history of poinsettias and their place in the market, the authors provide detailed chapters about propagation, growing on, nutrition, pest and disease control, pot and cut flower culture, postharvest care, and marketing. Colour photos throughout.
Producing The New New Guinea Impatiens
This has long been a gardening favourite, as reflected by its strong retail sales year after year.
BY MIKE FERNANDEZ
A longtime garden favourite, New Guinea impatiens can be an easy growing option for the greenhouse producer as well, with a few simple tips and techniques. That is true of the newer sun loving varieties like Sun Harmony as well.
This series provides all of the same features that have made New Guinea impatiens so popular, with the added advantage and versatility of growing in partial shade and full sun alike. Sun Harmony varieties, for example, are well branched with a lovely mounded and compact habit. Plants are covered in large 5 cm flowers and excel in both the ground and containers.
Rooting and transplant: For rooting, choose a light, well draining peat media. Keep pH at 6.0 to 6.5, and maintain electrical conductivity (EC) at
approximately 0.6 to 0.8.
Apply a preventive fungicide spray at sticking to protect from botrytis.
Maintain greenhouse temperatures at 22 to 24 C (72 to 75 F).
Keep soil moderately dry. No fertilizer in the mist is needed. Light levels should be high – 5000 foot-candles or more.
Time to transplant should be approximately four weeks for well-rooted liners.
Plant in January to March for a spring finish. From a 10 cm (4 to 6 inch) pot, plants will be ready for sale in eight to 10 weeks. Plant one plant per pot and three per pot with 25 cm (10 inch) pots or hanging baskets, and plants will be ready for spring sale in eight to 10 weeks.
MAIN Sun Harmony™ Baby Pink. BOTTOM Harmony™ Orange.
9:35 - 10:00 AM
Trials grower Emma Johnston of Jefferys Greenhouses will provide an overview of the trials.
10:00 - 10:25 AM Gary Vollmer of Selecta: “Starting Out On the Right Foot.”
11:40 - 11:55 AM
Dr. Sarah Jandricic (OMAFRA): “Insect Biological Control.”
11:55 AM - 12:10 PM Graeme Murphy (IPM specialist): “Insect Chemical Control.”
11:15 - 1 1:40 AM
Sirekit Mol (Beekenkamp): “European Trends.”
10:25 - 10:50 AM
Dr. Harvey Lang (Syngenta): “Finishing the Crop.”
10:50 - 11:15 AM
Dr. Allen Hammer of Dümmen Orange: “Varieties and Pot Sizes in the North American Market.”
12:10 - 12:30 PM Panel discussion 12:30 - 1:00 PM Lunch Provided. 1:00 - 3:00 PM Time to tour the trials.
Media: Select a well draining diseasefree medium. Keep pH at approximately 6.0 to 6.5, and maintain electrical conductivity (EC) at 0.6 to 0.9.
Fertilizer: For the first two weeks, keep fertilization at low levels (50 ppm nitrogen mist). At week three after transplant, begin feeding 65 to 80 ppm
nitrogen in a well-balanced fertilizer. This should be about the time roots reach the sides of the pot. Avoid salt accumulation, as Sun Harmony can be sensitive to high salt levels. Proper runoff should prevent this.
Light: New Guinea impatiens prefer high light levels, a minimum of 5000
foot-candles.
PGRs and pinching: Sun Harmony may need plant growth regulators (PGRs). Both Sumagic and Bonzi are effective at low rates. If needed in weeks six to 14, drench with Bonzi at 1/10th of 1 ppm and up to 1/2 if needed.
Temperatures: Daytime temperatures should be 18 to 28 C (68 to 72 F). Maintain nighttime temperatures at 16 to 21 C (68 and 70 F). Stem elongation can result from overly high temperatures.
On the other hand, low temperatures can cause plants to be too compact. If grown cooler, add more production time to the crop.
Watering: Keep plants evenly moist, and avoid overwatering.
Pest and disease control: Maintaining moderate humidity levels and providing good air circulation should be part of any good preventive program. Preventing insect or disease activity starts with vigilant scouting and monitoring.
Watch for insects including thrips and broad mites, and scout for diseases including myrothecium and botrytis.
For more information on Sun Harmony or any of Danziger’s products, visit www.danziger.co.il.
Mike Fernandez is North American product manager for Danziger “Dan” Flower Farm. He can be reached at mike@danziger. co.il.
FOR MORE CROP CULTURE ARTICLES, VISIT THE “INPUTS” SECTION AT
LEFT Sun Harmony™ Blush RIGHT Sun Harmony™ Scarlet.
Substrate enhancer
Growers can now rely on Retain substrate enhancer to help them with water management and nutrient management in a wide variety of crops. Retain can be mixed dry or pre-hydrated into soil and soilless media. It works well with both soil as well as soilless media. It is suitable for a wide range of uses, including hanging baskets, potted plants, bedding plants, gardens, trees and shrubs, lawns and hydroponics. www.RainSoil.com
WaterPulse milestone
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INSIDE VIEW
GARY JONES | Gary.Jones@kpu.ca
Recalling Early Challenges Concerning Recirculation
Preparation for painting my home office/study recently required a serious clearing out, and I undertook a somewhat enforced go-through of my filing cabinet. You know the feeling. (If you don’t, do it sometime, it’s pretty liberating. But be warned, it will take you much longer than you think!) Three drawers packed tight with technical crop information from the late ’80s onwards. (Now you see why it was liberating.)
Photocopies of articles, confidential Ministry technical releases, faxes (Google it if you’re too young to know), even microfiches (ask your grandfather). Of all of these, hand-written notes brought memories back of grower visits, meetings and conversations as if they were just yesterday. (For any students reading, it’s been shown that typing notes into a laptop fails to generate the same level of long-term memory. Just sayin’, like.) I even came across a copy of Volume 14, Numbers 7 & 8 (July-August 1991) of Alberta Technical Notes, edited by a certain Dr. Mirza Mohyuddin. (Mirza’s gift when visiting me in Sussex, U.K. at that time!)
In the “For Sale” section at the back, apart from two greenhouse businesses for sale, Joe Doef was selling a 1977 Dodge postal van, “heated with rollup door.” No price mentioned.
Given the theme of this month’s Greenhouse
Lambie closed with, “At present there is no clear view as to which [disinfection] system will succeed. Much more research is needed before any major investment is carried out on the nursery (greenhouse).”
Stuart also pointed out that “maintaining healthy roots is key to success.” Some concepts are just timeless, but we often forget that oxygen is an essential plant nutrient just like the solid and liquid ones we put in the feed tanks, and we’d do well not to forget that. Plants with roots that are stressed due to oxygen depletion are more susceptible to root diseases than are healthy roots. I’m sure Dr. Mohyuddin (yes, the same one from 1991 Alberta Tech Notes!) has even discussed this in recent issues of this magazine!
What of this rather reflective trip down the memory lanes of horticulture?
We often forget that oxygen is an essential plant nutrient.
Canada, one particular article caught my eye.
In his 1990 piece entitled “Testing the case for recirculating nutrients”1, Stuart Lambie, then a technical advisor for Grodan, discussed the potential challenges of the (then) new concept of re-circulating the nutrient solution in rockwool growing systems.
He mentioned the probable savings in feed and water costs, but also pointed out “there is little practical knowledge of how to deal with crop nutrition, cope with the build-up of sodium, chloride and sulphate levels and clean recirculated water –or of which systems actually work.”
He posed two major questions that “still need to be answered” (“How should the feed program be modified?” and “How should the return feed be cleaned of bugs and diseases?”) and described 12 possible configurations for channel systems.
Well, we’ve come a long way in the intervening 27 years and gone a very long way to answering Stuart’s questions. For example we have gutter systems that are now pretty much industry standards. We have ion-specific electrodes and nutrient management systems that can adjust return feed solutions to intended recipe targets. And we have multiple options for effective disinfection of dirty return solution. Answers have come through government-funded research, supplier innovations to meet market-place needs and the hard work and curiosity of growers. Progress in our industry is always a team effort.
But as well as the timeless concepts (such as healthy roots!), we realize that we’ve never quite “got there” – there is always something new to discover, a better way of doing things, new ideas to move forward. I wonder what we’ll look back on in another 27 years as new ideas that will then be common place.
One question remains however. Did Joe Doef ever sell his ’77 Dodge postal van? Joe?
1 Lambie, Stuart, “Testing the case for recirculating nutrients,” Grower magazine, August 1990.
Gary Jones is co-chair of Horticulture at Kwantlen Polytechnic University, Langley, BC. He serves on several industry committees and welcomes comments at Gary.Jones@kpu.ca.
• Real-time, highly accurate WC, EC and temperature data
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