Using 3D printers for prototyping allows you to tweak custom designs without expensive mould changes. | 34
Eggplant consumption – particularly exotic varieties not previously grown here – is increasing at an impressive pace. | 30
VINELAND RESEARCH AND INNOVATION CENTRE PHOTO
Issues 10 Keyhole Garden is a New Buzzword for the Industry
Issues 12
Worry About Filling Key Vacancies Shading Trials 20 Which Type Performs Best in Greenhouses?
3D Printing 34 Could This Technology Be a Game-Changer?
Farming In The City 44 It’s Easy to Understand Why Urban Agriculture is Booming.
50 Are LEDs the right choice for my operation? Growers looking to meet their long-term lighting needs.
DR. YOUBIN ZHENG
Root health can be your hidden wealth Pair of growers in Western Canada offer their insights
BY DR. MOHYUDDIN MIRZA
Growers weigh in on the many benefits of screening. Some farms are even using double screens.
BY GARY JONES
Weighing the ‘costs’ of eating healthier
Do consumers really appreciate the value they get with fresh vegetables?
There are definitely two sides to this question.
We’ll start with the positives.
First case in point: this year’s Food Freedom Day fell on Feb. 9, about three days later than 2014, largely due to our sinking loonie and its impact on imported produce. However, Canadians are still only paying about 11 per cent of their disposable income on grocery bills for the year.
Second case in point: the many health benefits of fresh vegetables are widely understood, thanks to the marketing efforts of various government agencies, grower groups and disease awareness associations.
• We’ve all grown up with the “seven to 10 servings of fruit and vegetables per day” guidelines of Health Canada.
• The USDA’s Dietary Guidelines are a little more robust, recommending adults eat between five to 13 servings of fruits and vegetables per day.
Key to the success of the program has been the number of major retailers who supported it.
So what are the negatives in this discussion? For starters, despite all the health promotion campaigns, Statistics Canada reported that in 2011 only slightly more than 40 per cent of Canadians ages 12 and older consumed fruit and vegetables five or more times per day.
And then there’s “price.” Here’s where the argument gets most frustrating. The Half Your Plate website noted that in a January 2016 sampling in Toronto, $10 would buy half a pound of peppers, a pound of apples, a pint of cherry tomatoes, one cucumber, a three-pound bag of carrots, a pound of onions and one avocado.
You’d probably pay about the same for a weekend’s worth of junk snack food…but without the nutritional boost.
Food Freedom Day fell on Feb. 9, about three days later than 2014.
Third case in point? The “Half Your Plate” program is brilliant. It has been developed and promoted by the Canadian Cancer Society, the Heart and Stroke Foundation of Canada, the Canadian Public Health Association, and the Canadian Produce Marketing Association.
Half Your Plate simply encourages consumers to fill half their plates with fruits and vegetables with every meal. “Increased consumption of fruit and vegetables,” notes the website, “has been proven to reduce the risk of chronic diseases such as some cancer, heart disease and stroke.”
In various media reports over the past winter we’ve heard of consumers grumbling about the rising price of fresh winter produce, most of which is imported. The dollar’s decline is making it much more expensive to buy these goods. Paying $2.99 for a stalk of celery in January prompts a grumble, but paying $2.99 yearround for an average size bag of potato chips is par for the course.
The search term “healthy snacks” yielded 92,500,000 results. It’s trending. Far and away the majority would include fresh produce, and much of it can be grown in greenhouses. This is just another reason growers here should push for increased research into both yearround production and alternative crops.
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Green Careers Canada Now Online
Landscape Ontario and the Canadian Nursery Landscape Association have launched a new online resource for green profession educators and students across Canada.
Green Careers Canada (www.greencareerscanada.ca) is designed to provide easy access to information about landscape and horticulture jobs, courses, scholarships, bursaries and apprenticeships in each province. It also promotes awareness about
green career options to guidance counsellors, co-op teachers and policy makers.
Green Careers Canada also has an interactive component, where students and professionals share their educational and industry experiences through video interviews.
Updated regularly, Green Careers Canada also presents a comprehensive list of events and information related to the industry.
NEW OMAFRA FLORICULTURE SPECIALIST
Dr. Chevonne Carlow recently joined the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) as its greenhouse floriculture specialist.
Carlow will be working to connect growers with information on floriculture crop production and related issues.
In addition, she will be working on collaborative research and demonstration
projects related to the floriculture sector. She takes over from Wayne Brown who retired from the position last year.
Carlow enjoys the unique challenges that come with producing top-quality plants.
She first became interested in working with plants while attending the University of Western Ontario as an undergraduate student. Following graduation she enrolled in a Master’s program
at the University of Guelph. There she worked on understanding the effects of shading and light ratios on young plant development.
PLANT STRESS RESPONSES
Following that, she moved on to study plant stress responses while working to complete her PhD at the University of Guelph. During that time, she also taught introductory
plant biology through lab demonstrations.
Carlow is excited to be a part of the Ontario floriculture industry and is meeting as many growers as she can throughout this winter and into the spring season.
She is located at OMAFRA’s Vineland office and can be reached at 905-5634141, extension 179, or through email at chevonne.carlow@ ontario.ca.
$2B Estimated spending on Valentine’s Day flowers in U.S., 2016
Retail Federation)
NEW VARIETIES
Warm up combinations with sunny Beedance bidens from Suntory Flowers. ‘Painted Red’s’ petals are half redorange and half yellow, becoming redder in cooler temperatures. ‘Painted Red’ (pictured) won the Innovation Award at IPM Essen in Germany for best new bedding and balcony plant, and best new annual at the HTA National Plant Show in the United Kingdom. ‘Red Stripe’ has yellow
flowers with unique red stripes on each petal. Benefits include early flowering, continuous flowering and manageable plant habit. Beedance has shorter internodes but flowers still mingle nicely in combinations. Plants are seed sterile but still produce pollen. Cutting sales will support honeybee health research through the Pollinator Partnership. suntorycollection.com
This impressively vigorous, landscapesized Lantana from Proven Winners forms a mounding then trailing mass of dark green foliage dotted with pretty pink and light yellow bicolour blooms all season with minimal seed set. Use it as a groundcover, in mono pots, or in large containers with other very vigorous plants. Provide high light and warm conditions for best growth. It is 20-24” tall with a 24-36” spread. It works best in full sun. provenwinners.com
Extend your season – add this heat lover! Compact, upright habit with eye-catching burgundy colour, ‘Little Zin’ Hibiscus from Ball Floraplant is perfect for summer combos. Hibiscus rooted cuttings should be ready for transplanting 21 to 28 days after sticking. ‘Little Zin’ should be kept evenly moist with some drying between waterings to give the most consistent quality growth. When plants are young, allow the media
to dry slightly between watering. Excessive moisture for prolonged periods can cause plant stretch and undesirable growth habit. Pinch plants back seven to 10 days after transplanting to improve basal branching. It grows 1824” (46-61cm) tall by 18-24” (46-61cm) wide. The attractive dark burgundy foliage pairs well in combination with other plants. ‘Little Zin’ thrives in the heat and full sun.
ballfloraplant.com
With tremendous impulse appeal at retail, ‘Superbena Sparkling Amethyst’ from Proven Winners bears large clusters of amethyst purple flowers kissed with rosy purple centres. The flowers completely cover the canopy of dark green, powdery
mildew-resistant foliage all summer without deadheading. This plant makes a perfect 4” Grande pot but becomes a vigorously spreading plant for the consumer as it matures. It is an excellent spiller in combination planters and hanging baskets. provenwinners.com
‘Salmon’ is the latest addition to the Surfinia Summer Double petunias. This uniform series in the Suntory Collection is early flowering and grower friendly. Unlike other double petunias, Summer Doubles offer outstanding heat and rain tolerance and award-winning garden performance. Dead flowers do not stand out as new blooms cover old. This series is excellent in combinations. ‘Salmon’ is two weeks earlier than the rest of the series. Also new in Surfinia Summer Doubles is the Double Romance combination, featuring ‘Rose,’ ‘Pink’ and ‘White’ – three perfectly matched varieties. Command a premium with this unique combination that is perfect for Mother’s Day sales. suntorycollection.com
YaraLiva Calcinit
The reliable source.
Rely on YaraLiva for your crops
YaraLiva Calcinit has the consistent quality and reliable performance necessary to maximize your crop’s yield. Yara’s portfolio of products includes the new YaraLiva Calcinit K, a nitrate, calcium and potassium source. Yara has a full range of solutions for greenhouse growers.
Rely on it for the environment
The carbon footprint of Calcinit and Calcinit K is four times lower than most others in the industry. With a catalyst that took 10 years of research to develop, Yara’s exceptional environmental stewardship means a greater contribution to sustainability.
Rely on YaraLiva
For better quality crops that are longer lasting and have better freshness and appearance, the clear choice is YaraLiva Calcinit, the world’s best-selling calcium nitrate.
A Key to Sustainability
Keyhole Gardening a New Buzzword for the Industry
Teach a village how to garden and it will prosper for a lifetime. That’s our aim at Vita Gardens.
Based in Sarnia, in southwestern Ontario, we work to bring life to all through innovative garden technology. Inspiring people to grow healthy food through unique and responsibly designed raised bed gardens is our mission.
Keyhole gardening is one of those buzzwords that seems to be taking over the industry. The keyhole gardening method was developed in Africa as a way to grow food in severe drought and extreme heat. It works by creating one raised bed for both growing and composting and uses up to 80 per cent less water than conventional gardening beds.
ABOVE
Eddie
To us, it was an idea that seemed too good to be true. How could one compact unit use less water, compost and grow abundant crops at the same time? We created an updated version that does just that – and eliminates the need for kneeling or bending over.
After the bed is loaded with green and brown composting materials, gardeners collect scraps and water through the built-in compost tunnel. This is key to reducing evaporation and allows plants to develop strong, healthy roots that are more resistant to drought.
Growing plants in the keyhole garden is easy. Any vegetable or ornamental that grows in a traditional garden can grow in a keyhole garden.
While most common vegetables work well in this raised bed garden, tomatoes and kale tend to thrive in both North America and Africa.
OUR JOURNEY
Last summer, we wanted to give back with something more concrete than a corporate nod or a few cheques. We wanted to be involved with keyhole gardening personally and pay respect to the region that invented this practice. To do this, we partnered with an organization called Africa New Life to build 10 keyhole gardens in Kigali, Rwanda.
Physically building gardens in Rwanda allowed us to see the real needs on the ground. We decided to purchase all local materials to build the gardens so we could support the local Kigali economy. This included stitched rice sacks as the structure, sticks for the framing, and surrounding dirt for the soil.
The dirt was – without exaggeration – like concrete. It had been sun-baked to a rock hard crust since the last rainy season. We first had to fracture the hardpan, lift it, and then pulverize the dirt into something usable.
I will never forget the people we met over the summer. Rwanda left me speechless.
I saw a 73-year-old woman reach out to the heavens in gratitude as she danced joyfully around her keyhole garden. With tears in their eyes, I saw grown men at a loss for words, wondering why we would travel halfway across the globe to help them. I saw a 92-year-old man improve his eyesight after I gave him my old prescription glasses.
Teaching communities how to sustain themselves is a life skill. The great thing about keyhole gardens is that they can be made out of nearly anything. The average cost for constructing, training and materials for a keyhole garden in Rwanda is around $100.
While keyhole gardens are convenient and efficient, the benefits they provide are also longlasting and impactful. After a few short months, our new friends began harvesting lettuce and other crops from their keyhole gardens. We’re excited to watch the community continue to grow.
For more information about Vita Gardens, visit vitagardens.com.
Eddie DeJong is the head of business development and design for Vita Gardens.
DeJong of Vita Gardens helped create 10 keyhole gardens in Kigali, Rwanda.
A Growing Skills Shortage
Half of Employers in Survey Worry About Filling Key Vacancies
Many employers are struggling to fill in-demand positions, unable to find candidates with the skills they need.
In fact, half of all employers surveyed feel there is a shortage of skilled workers in Canada, according to a recent survey from CareerBuilder.ca. The survey also found that three in 10 employers (29 per cent) currently have positions in their organization that, on average, stay open for 12 weeks or longer. Of those with extended job vacancies, 75 per cent say the vacancies have adversely affected their firm.
“Companies nationwide are feeling the effect of a skills gap, from lower morale to higher retention rates to a loss of revenue,” said Ryan Lazar, managing director of CareerBuilder Canada. “Our findings indicate, however, that taking proactive efforts to train and re-skill workers can go a long way in overcoming these challenges. While we still have a long way to go, the more we can identify the root of these challenges, the more opportunities we will find to bridge this gap.”
Morale, productivity and retention are among the victims of extended vacancies, according to employers. When asked how extended job vacancies have adversely affected their firms, employers cited the following results:
• Work does not get done (31 per cent).
• Lower morale due to employees shouldering heavier workloads (26 per cent).
• Delays in delivery times (24 per cent).
• Lower quality of work due to employees being overworked (23 per cent).
• Employees are less motivated (23 per cent).
• Loss in revenue (22 per cent).
• Declines in customer service (20 per cent).
• Higher turnover because employees are overworked (19 per cent).
• Employees making more mistakes, resulting in lower quality of work (14 per cent).
When asked what they think is causing the skills
shortage, employers offered the following opinions:
• Not enough graduating in in-demand fields (52 per cent).
• Lack of interest in required fields (48 per cent).
• Employers and candidates have different expectations (41 per cent).
• Entry-level jobs are becoming more complex (37 per cent).
• Lack of funding in necessary training (36 per cent).
• Rapid changes in technology (34 per cent).
• Increased competition for candidates (33 per cent).
In an effort to overcome these challenges, many employers are taking matters into their own hands and training workers on the job. Forty-six per cent of employers say they have hired a low-skilled worker and trained him or her for a higher-skill job within their firms in the last two years. When asked how this practice has affected their firms, employers cited the following benefits:
• Increased employee motivation (50 per cent).
• Improved employee loyalty (47 per cent).
• It enabled us to be more competitive (46 per cent).
• It enabled us to meet department goals (41 per cent).
For some employers, automation may be the answer to their staffing challenges. Three in ten (28 per cent) foresee certain jobs at their organizations being replaced by technology in the next decade.
When asked which areas they see being replaced by technology, employers identified customer service (42 per cent), IT (34 per cent), shipping/distribution (32 per cent), accounting/finance (27 per cent), and sales (12 per cent).
The survey was conducted among 500 employees and 400 hiring managers across Canada.
Retain is a multimedia website delivering the pension and benefit information small and medium sized businesses need to recruit and retain top talent. It is published by Annex Business Media, a business-to-business media company reaching over 40 markets across Canada.
FAR LEFT
Half of all employers surveyed feel there is a shortage of skilled workers in Canada.
CENTRE LEFT
Job training programs are effective.
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Are LEDs the right choice for my operation?
Growers are increasingly looking at them to meet their long-term lighting needs
BY DR. YOUBIN ZHENG
After presenting a webinar through Greenhouse Canada last fall, and a few talks at different occasions on light-emitting diodes (LEDs) and their applications in horticulture, I have been more frequently receiving phone calls and emails regarding LEDs. The majority of the questions are:
• Are LEDs the right choice for my operation and how can I figure this out?
• There are so many LED suppliers, which shall I choose?
To address the above questions, let me start with some basics about LEDs, light (scientifically it should be called radiation, but we will use light here), and plants.
What are LEDs? LEDs are solid-state
semiconductor devices that produce narrow spectrum light when voltage is applied. Different semiconductor materials can produce different light spectrum. Commercially available light spectra which are relevant for plant growth and development range from 215 to 910 nm which includes: ultraviolet, violet, blue, green, yellow, orange, red, far red, and near infrared.
LEDs emit little or no radiant heat, however high-output LEDs do generate significant amounts of heat from the diode junctions, which needs to be removed to prevent overheating and possible damage to the LED array.
Although the first LED was patented in the 1960s, application of this technology in plant
TOP Leaves of tomato grown under white LEDs (with high blue content) as the sole lighting source. ABOVE RIGHT Dr. Youbin Zheng, University of Guelph.
research only began in the 1990s, mainly in NASA’s advanced life support research group. Since that time, many studies have been carried out and LED technologies are now in a period of rapid development with dramatic increases in energy efficiency and decreases in price.
Light and plant production: Light can control plant growth rates through driving photosynthesis, modify colour and morphology (e.g. internode length, leaf shape, size and thickness), and affect flowering etc.
Wavelengths between 400-700 nm are effective in driving photosynthesis. However, different wavelengths have different quantum efficiencies (i.e. a measure of the conversion of light, expressed in terms of number of photons incident on a leaf surface over a specified period of time, into photosynthate). In general, red (600-700 nm) has the highest efficiency, then blue (400-500 nm) which is about 25 per cent lower than that of red; green (500-600 nm) has the lowest efficiency.
Most plant morphologies are controlled by wavelengths in the nearultraviolet (380-400 nm), blue (400500 nm) or red and far-red regions (600-700 nm and 700-800 nm). Blue and near-ultraviolet are necessary for the development of chlorophyll and other pigments (e.g. anthocyanin and carotenoid); therefore, these wavelengths can make plants greener or be used to promote certain medicinal or beneficial second metabolites.
Blue light also stimulates stomatal opening, therefore increasing photosynthetic potential; and high blue light content light fixtures can keep internodes short. Excess of farred can stretch internodes. Plants not only respond to different light spectrum and light intensity, but also respond to the ratios of different light spectra. For example, high far-red/red and/or red/blue ratios can induce plants to be stretched, and lowering these ratios can promote plants to be more compact.
Changing light environment can also promote or delay plant flowering. Some photomorphogenic responses may be induced by very low intensities (ex. <1.5 µmol·m-2·s-1 of specific spectra).
Different plant species respond to light differently. For example, research showed that using red light alone to provide long day conditions for chrysanthemum can keep plants vegetative; however, red light can increase the number of flowers and
buds in begonia. Therefore it is important to investigate the published lighting research relevant to the crops you are growing.
Armed with the above information, it is easier to understand the advantages and disadvantages of using LEDs in comparison to using some of the conventional lamps.
ADVANTAGES OF LEDS
1. Increasingly better energy efficiency (i.e. conversion of joules of energy to photons of photosynthetically active radiation). Research showed that LEDs were more efficient than incandescent and fluorescent lamps and on par with lamps such as high-pressure sodium (HPS) by as early as 2008. Before 2008, their efficiency was increasing 30 times per decade with a corresponding 10 time decrease in production cost (Bourget, 2008). This trend continues.
Some researchers speculate that the electrical efficiency of red LEDs will be double that of HPS lamps by 2020. When comparing the electrical efficiencies of lighting technologies, it’s best to base comparisons on light
quanta (the production of µmoles of photosynthetically active photons per joule of electricity input).
It is important to have an understanding of the lighting distribution provided by different LED systems as well. Very specific instrumentation (ex. an integrating sphere) is needed to assess the total light output of a particular fixture. Total light output is, however, only one part of the equation when integrating any light fixture into a specific plant production scenario. Equally important are the interrelated factors of the: 1) light distribution pattern of a given fixture; 2) hang height; and 3) lateral positioning (i.e. light overlap) of adjacent fixtures.
It is an oversimplification to assume that all of the light produced by a fixture will reach the crop. This is important to keep in mind when comparing LED technologies supplied by different companies, as well as comparing LED technologies to other lighting systems, such as HPS.
2. LEDs can provide specific wavelengths (i.e. light spectrum). This is actually one of the most unique capabilities of LEDs. LED technology can
How You Grow Matters
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provide lighting fixtures with different (sometimes customizable) spectra and different spectral combinations at different (sometimes user-adjustable) ratios. This can provide growers with endless opportunities for using light as a tool to “manage” their crops – something the conventional lighting systems simply cannot provide.
3. LEDs are dimmable and can be rapidly cycled between on and off, and anywhere in between. This has the potential to give the greenhouse grower the power to integrate feedback control (based on ambient light levels) to modify the supplemental light intensity in real time, thus providing only the amount of light that a crop needs, ultimately resulting in further energy savings. While LED technology has this capability, it is not presently being widely used in commercial settings.
4. LEDs can have more focused light. If you have narrow benches and wide walkways in the greenhouse, a more focused light can waste less light energy. However, less focused light can cover a wider floor space.
5. LEDs emit a small fraction of the radiant heat that conventional lights do. Therefore we can keep the light very close to the plant canopy without the risk of harming the foliage. This is extremely useful for tissue culture and seedling propagation, especially for producing plants with multilevel indoor facilities, to save space. LEDs can also be used for inter-canopy lighting in greenhouse vegetable production.
6. LEDs have much longer lifespans. Most LEDs can last up to 100,000 hours, and the HPS lamps have a lifetime ranging from 10,000 to 20,000 hours. In other words, good LEDs have more than five times longer lifetimes than HPS.
DISADVANTAGES OF LEDS
Compared with some of the conventional lighting systems, LEDs also have a few disadvantages.
1. Expensive. Even though the price has been dropping rapidly in the past few years, horticultural LED technologies are still more expensive than some of the conventional lighting systems, such as metal halide and high-pressure sodium lamps.
2. LEDs do not emit that much radiant heat. Conventional lighting systems, especially HPS, can produce heat to warm up and dry leaf surfaces faster. Radiant heat from the lighting can
be an advantage in certain circumstances, such as in keeping leaf surfaces dry in order to reduce the occurrence of powdery mildew. This is one of the reasons that some greenhouses are using mixed LEDs and HPS in their production environments.
3. Some LED fixtures have large footprints that tend to block the natural sunlight when used in a greenhouse as a supplemental lighting source.
4. Some people do not feel comfortable working under certain light colours. One measure of the colour of a light source is the Color Rendering Index (CRI). A CRI of 80 or more is recommended for office and other workplaces. Similar to fluorescent lamps, some white LED lamps can provide a CRI of 70-90. However, most of the LEDs used as greenhouse supplemental lighting are predominantly red and blue. Under this type of lighting, the colour appears pink. Certain populations feel uncomfortable (e.g. dizzy) under this type of lighting environment. Further, it can be difficult to visually assess the health (including the “greenness,” prevalence of disease, etc.) of a crop grown under LED lights.
5. Not enough research has been conducted for most plant species. We know that different plant species respond to changes in the lighting environment in different ways. To apply LEDs to specific crops, the grower needs to find out the best spectral combinations to fully utilize some of the advantages of LEDs.
While the literature is increasing exponentially, there are still tremendous knowledge gaps for most commodities.
ARE LEDS THE RIGHT CHOICE FOR MY OPERATION?
To address this question, let’s consider two separate scenarios of horticulture lighting applications: 1) sole source, and 2) supplemental lighting.
1. Indoor crop production with artificial light as the sole lighting source. If your operation is using artificial lighting as the sole lighting source, especially in multilayer growing systems, then LEDs are your best choice. LEDs can be arranged very close to the plants without damaging leaves from radiant heat; therefore the plant supporting layers can be placed closer to maximize your space use efficiency. The applications of LEDs in indoor plant factories have been demonstrated in a few countries in recent years, and some LED suppliers have accumulated valuable knowledge and experience to share with you when consulting on your particular application in your facility.
When using LEDs as the sole lighting source, it is very important to know the best light intensity and light spectra to use. Different plant species may respond to these parameters differently. When light spectra are not correct, or when there is an imbalance of certain wavelengths, plants may show abnormal growth and morphology, such as bumps on leaves (See photo on page 14). Also, light saturation points and optimum light levels vary among different crop species and lighting environments. By understanding these, you are able to increase the return on your lighting energy inputs.
2. Greenhouse production with artificial light as a supplement to natural lighting. LEDs can be used in greenhouse supplemental lighting scenarios for certain crops. For example, our research showed that red and blue LEDs can be used to replace HPS as supplemental lighting for cut gerbera production. Studies from the U.S. showed that LEDs can be used to replace HPS for producing some bedding plants and plugs. Research also demonstrated that LEDs can be used to
provide inter-canopy lighting for fruit and vegetables, such as cucumber and tomato plants. However, when considering using LEDs to replace conventional lamps such as HPS, economics need to be taken into consideration. We will discuss this later.
LEDs are especially useful for producing nutraceutical and medicinal crops. As discussed earlier, certain wavelengths are able to enhance the production of certain secondary metabolites. For example, a study conducted at the University of Arizona showed that after 12 days of light quality treatment in baby lettuce, the concentration of anthocyanins increased by 11 per cent and 31 per cent with supplemental UV-A and B, respectively, and the concentration of phenolics increased by six per cent with supplemental red compared to those in the white light control. This advantage can be applied in both supplemental and sole source lighting scenarios.
Some secondary metabolites also have anti-microbial and insect deterrent properties; therefore, LEDs may be used to induce certain plants to be more resistant to pests.
CONSIDERATIONS WHEN CHOOSING LEDS
1. Economics: We know that some LEDs can be more energy efficient, have much longer lifetime, can be more focused, and can be used to save space. We also know LEDs are more expensive and that electricity rates vary according to geographic region and time of use. We also know that some regions have incentive programs for installing energy-saving lighting fixtures, and that there is a significant range of prices from different LED suppliers.
There are many factors to consider when doing cost-benefit comparison of LED lighting technologies, making it very difficult to say how economical LEDs are. Having said that, when considering whether to use LEDs or HPS as supplemental lighting in a greenhouse production operation, it would be advisable to ask lighting fixture suppliers to provide you with quotations (e.g. number of units needed, and the unit price) based on the average light (400-700 nm) intensity (µmol·m-2·s-1) you are trying to achieve at the crop’s canopy height. Based on the quotations and light specifications (e.g. electrical efficiency, electricity consumption per light unit, the price for electricity, etc.), you are able to estimate the actual costs for getting different lighting units installed, predict their electricity consumption, and ultimately assess the most economical solution for different
periods of time (e.g. over five or 10 years, or over the predicted life of the fixture).
2. Not all LEDs are the same: As mentioned earlier, most of the LEDs are advertised as lasting up to 100,000 hours of use (number of years will depend on the daily photoperiod and the portion of the year that the fixtures are in use); however these lifetimes are based on low current and low temperature conditions. LED efficiency is inversely proportional to operating temperature.
For high-output LEDs used in plant production, the high current and high temperature can limit LEDs’ lifetime and efficiency if not cooled properly. To remove the heat from the diode junctions, different technologies are currently used, which includes: active (convection) cooling (ex. fans or water) or passive cooling (ex. by heat sinks connected to the back side of the LED arrays).
Moving parts are always a concern in the harsh greenhouse environment (ex. moisture, dust, large swings in ambient temperature). For example, if a cooling fan fails, the LED unit shuts down (assuming proper thermal protection) until the fan gets replaced. Overheating can also cause irreversible damage to the fixture. Therefore it is important to shop for LEDs with robust designs and reliable peripheral technologies.
Some LED fixtures have fixed spectra (e.g., certain blue and red ratio) while others have adjustable spectra. The latter may be more expensive, but they provide you with the potential to make full use of the advantages of LEDs mentioned earlier for your current and future production scenarios.
OUR EXPERIENCES WITH DOING LED RESEARCH
Since the mid 1990s, and especially in recent years, many studies have been carried out in different parts of the world investigating the applications of LEDs in horticulture and showing some very promising results. However there are still enormous knowledge gaps and a great need for further research and exploration.
For an example from my own lab, a few years ago (supported by the International Cut Flower Growers Association, LumiGrow and local greenhouse growers), we grew three cut gerbera cultivars under both LED and HPS supplemental lighting, at the same canopy-level light intensity (PAR). Results showed that cut gerbera yield and quality were equal or better under LEDs than under HPS. Extending from that research, we are now looking at determining the optimum canopy-level supplemental LED intensity for growing various cut flowers, including gerbera and snapdragons.
Additionally, with support from Ontario Ministry of Agriculture, Food and Rural Affairs, Heliospectra, Flowers Canada Ontario, and local greenhouse growers, we have just started a three-year project entitled: “Develop feedback control systems for optimizing the use of temporally variable, intelligent LED light systems to save energy and improve crop quality in greenhouse production.”
In addition to developing lighting system feedback control (based on ambient light level and set target Daily Light Integrals), we also will investigate using different light spectral combinations to manage ornamental crop quality, such as modifying R/FR ratio to control plant height, instead of using chemical growth regulators.
Dr. Youbin Zheng (yzheng@uoguelph.ca) is an associate professor and Environmental Horticulture Chair at the University of Guelph, who has more than 20 years experience in greenhouse and nursery crop production research.
LED research at the University of Guelph.
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WHICH SHADING Is The Winner in Florida Trials?
Diffused light results in more active leaves and better usage of light.
BY MAURICIO MANOTAS
When it comes to shading, which type performs best in greenhouses? Two recent studies conducted in Florida set out to find the answer by comparing the properties of three 60 per cent shades commonly used for nursery and greenhouse production.
Standard black and metallic external shades often spread light inconsistently, causing some plants to receive more light than others, requiring crops to be moved regularly. In contrast, lightdiffusing white shades allow light to penetrate deeper and more consistently, promoting even plant growth and less handling of the crop. This enhanced diffused light generates potential crop density increases – maximizing your profitability.
The aim of the two Florida studies – conducted by the University of Florida and at Brite Leaf Citrus Nursery – was to investigate if it is possible to lower air and leaf temperature and improve crop quality using a white light-diffusing open exterior shade compared to metallic and black shades.
In a trial performed at the University of Florida’s Gulf Coast Research and Education Centre, 12 metal-frame enclosures were clad with standard 6 mil clear polyethylene (poly) film.
Sixty per cent shade treatments, including a 60 per cent black shade (Shade Rite), 60 per cent metallic shade (Aluminet) and a 60 per cent white diffusive shade (Svensson 6420 Harmony O E) were randomly assigned and placed over the poly film. Interior ornamental plants (Dypsis lutescens or areca palm and Spathiphyllum spp. or peace lily) were placed in each enclosure. In addition to PAR, air temperature and relative humidity, plant-based measurements were included in the study.
In a separate trial at Brite Leaf Citrus Nursery in Lake Panasoffkee, Florida, two closed structure greenhouses with transparent double poly coverings and nets on the gables and sidewalls were equipped with a 50 per cent diffusive shade (Harmony 5120 O E) and a 50 per cent metallic Aluminet shade.
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HIGHER LIGHT, LOWER TEMPERATURES
Exposing plants to high temperatures leads to plant stress such as stomatal closure and reduction in net CO2 assimilation rate, growth and yield. If leaf temperatures are reduced, the plant will be less stressed and net CO2 assimilation rate and growth will be closer to its optimal point. Increased scattering of light generally increases the radiation use efficiency of a plant.
On the other hand, if light reduction is too excessive, net CO2 assimilation will become light limited and photosynthetic productivity will be reduced. Shading may also lead to changes in plant morphology and vegetative growth.
Both studies showed that the greenhouse and enclosures equipped with the open structure white light-diffusing Harmony shades had higher light levels and lower temperatures than the black shade and the metallic shade. Specifically, 15 per cent more PAR-light than black shade and eight per cent more PAR-light than the metallic Aluminet shade.
The Brite Leaf greenhouse with the fixed light-diffusing shade stayed 2.5 C cooler than the greenhouse with a fixed metallic shade. Climate data showed that every day during June and July the air temperatures were lower in the house with diffusive shade screens.
University of Florida researchers observed similar results: enclosures with the diffusive Harmony shade were 5 C cooler than black shade and 2.5 C cooler than metallic shade. Peak temperatures were lowered from above 40 C to 35 C. The study also recorded a lowering of leaf and soil temperatures in the diffusive screen house.
August and September had similar patterns to June and July regarding light and temperature. The differences in temperatures were smaller during August, and then the difference in temperatures increased again in September. Scientists surmise this could be due to heavy rainfall in August.
In the Photos A-B series: To the left,
a greenhouse equipped with Metallic 50 per cent Aluminet shade, to the right greenhouse equipped with 50 per cent light-diffusive white Harmony 5120 O E shade. Shade spots are clearly visible in the greenhouse at left; in the right greenhouse shade there are little to no shade spots as a result of light diffusive shade.
In the Photos C-D series (above): A trial at Brite Leaf Citrus Nursery in Florida compared temperatures, light levels and relative humidity of 50 per cent metallic shade versus 50 per cent white light diffusive shade.
WHAT DOES THIS MEAN FOR GROWERS?
Based on the results, growers would experience the following benefits when selecting a light-diffusing shade screen:
• Diffused light – More light all over the crop results in an increase in radiation use efficiency, more effective photosynthesis and therefore faster and improved growth.
• Reduced average temperatures – Citrus have limited growth above 34 C. If temperatures, on an average, are reduced from above 35 C to below 35 C, the result is an increase in the net CO2 assimilation rate and higher plant growth/yield.
• Reduced peak temperatures from 40 C to 35 C. During hot days with a lot of radiation, the temperatures in the greenhouse easily exceed 40 C under aluminum. At temperatures this high, the citrus plant becomes heat stressed. If peak temperatures are lowered, the plants become less heat stressed.
• Lower temperatures in the greenhouse may potentially lead to less use of water.
• Lower temperatures in general mean a more comfortable climate to work in.
• Better growth consistency – All plants get the same amount of light. Less frequent plant handling reduces labour intensities.
• Stronger and healthier plants – Light reaches deeper into each plant.
Mauricio Manotas is president of Ludvig Svensson, Inc. He can be reached at 704-357-0457, or Mauricio.Manotas@ ludvigsvensson.com.
Photos C-D. Commercial trials.
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Feeding the world is not just a big responsibility, it’s big business – with a world population over 7.3 billion, it has to be. However, many consumers don’t associate large-scale business with family business, even though 98% of
Canadian farms are family-owned and operated. As a result, many consumers don’t trust their food supply. We need to make sure the story of the family farm is being told, and that “big” doesn’t mean “bad.”
We all have stories we can share, whether you grew up on a family farm, or you work in an industry that serves farm families. Look for opportunities to tell the real story of Canadian agriculture, whether it be online, in the grocery store or at the dinner table.
Here are some talking points to get you started:
98% of Canadian farms are family farms
Almost all of the farms in Canada are family-owned and operated, and producing healthy, sustainable food is their first priority. Remember, farmers feed their own families the food they produce.
Family farms have evolved
They look different today than they did 50 years ago. But that doesn’t mean our food supply isn’t safe and healthy anymore. New technology has allowed farmers to do more with less, making agriculture more sustainable today. Farmers protect the environment because they want to pass their business on to the next generation.
Farming is a complex business
Families must manage food safety and traceability, detailed budgets and accounting, marketing, employees, everchanging technology, and more. Modern farms must be run as a business, and it makes good business sense for many family farms to incorporate. As a company, farms can minimize taxes. Plus, family members can own shares in the company, making it easier to pass the farm from generation to generation. But their business structure doesn’t change the fact that family members work side by side every day, bringing to life their shared passion and dedication for producing safe, healthy food.
We’re in this together
Everyone in the industry needs to work together to help improve perceptions. By being open and proactively communicating with the public about how we grow food and why we operate in the ways we do, we can maintain consumer trust and continue to produce high-quality, nutritious food in ways that are efficient and sustainable.
Social starters
The importance of family is something everyone can understand and relate to, whether you’re in ag or not. It’s common ground that can start a conversation.
Visit AgMoreThanEver.ca/resources to find a collection of photos that you can easily share on social media to start or support conversations about family farming.
The land is my lifestyle and my livelihood, but it’s also my legacy.
Providing safe, healthy food for my family is important to me too.
That’s why I farm.
I love ag for the life it gives my kids now…and the opportunities it gives in the future
Or, even better, share your own pictures and make your story personal.
Photo credit: CR Photography (Chantal Rasmuson) Pictured: Nate and Colin Rosengren
Photo credit: Aimée Ferré Stang
(photo by Jerri Judd)
What are others saying?
“Agriculture is a fast-growing business, and it has to be run as a business. It involves family, of course, but we’re always looking at the latest research, we’re looking at what practices are evolving in other countries, and we’re adapting those practices so we can become more efficient to get our product into the marketplace.”
“My farm is a family farm. It is 100% owned by myself, my husband and his two parents. We love everything about agriculture with a fierce passion. We have never, ever, sold a product that we wouldn’t happily serve to our children. Every decision on the farm takes more than just finances into consideration. Our number one goal is to leave a farm to our children that is both environmentally and economically viable.”
– John Thwaites, Ontario fruit and vegetable grower
– Adrienne Ivey, Saskatchewan rancher
Looking for more?
Watch The power of shared values webinar featuring Charlie Arnot, CEO of the Center for Food Integrity, who shares three simple steps to gain consumers’ trust by tapping into the power of shared values. Charlie helps bridge the divide between science and consumer perception and offers great insight into creating messages that are proven to resonate with consumers.
Visit AgMoreThanEver.ca/tag/webinar
AGvocate Challenge
There are 2.1 million Canadians working in agriculture and agri-food. Imagine the impact we could make if we all made a commitment to improve perceptions of agriculture. There are simple ways you can start being an agvocate today. Just choose to do one of the following:
1. Search the hashtags #FutureFarmer, #AgMoreThanEver, or #Farm365 and find a positive post to retweet.
2. When you overhear a misleading or inaccurate conversation about farming, find an appropriate time to share your story.
3. Dedicate one day to volunteer at an event that promotes agriculture such as Open Farm Days or Ag Literacy Week
4. Tell a friend or co-worker about the need to speak up, and ask them to take the agvocate challenge.
The power of shared values
We all share the same table. Pull up a chair.
“ The natural environment is critical to farmers – we depend on soil and water for the production of food. But we also live on our farms, so it’s essential that we act as responsible stewards.”
– Doug Chorney, Manitoba
“ We take pride in knowing we would feel safe consuming any of the crops we sell. If we would not use it ourselves, it does not go to market.”
– Katelyn Duncan, Saskatchewan
“ The welfare of my animals is one of my highest priorities. If I don’t give my cows a high quality of life, they won’t grow up to be great cows.”
– Andrew Campbell, Ontario
Safe food; animal welfare; sustainability; people care deeply about these things when they make food choices. And all of us in the agriculture industr y care deeply about them too. But sometimes the general public doesn’t see it that way. Why? Because, for the most part, we’re not telling them our story and, too of ten, someone outside the industr y is
The journey from farm to table is a conversation we need to make sure we’re a part of. So let’s talk about it, together
Visit AgMoreThanEver.ca to discover how you can help improve and create realistic perceptions of Canadian ag.
GROWING THE Exotic Eggplant Market
Eggplant consumption – particularly exotic varieties not previously grown in Canada – is forecasted to increase 130 per cent by 2030 to 55 million kilograms.
BY VINELAND RESEARCH AND INNOVATION CENTRE
Dr. Viliam Zvalo is Vineland’s research scientist in vegetable production systems.
With the highest per capita immigration rate in the world, Canada’s produce consumption is continually evolving.
Based on Statistics Canada reported patterns of growth over the last five years, eggplant consumption – particularly exotic varieties not previously grown in Canada – is forecasted to increase 130 per cent by 2030 to 55 million kilograms.
This is a market currently largely supplied by imports.
A team at Vineland Research and Innovation Centre (Vineland) is investigating varieties with commercial potential for production in Canada to meet this growing consumer demand and replace imported produce with local.
Dr. Viliam Zvalo (below), Vineland’s research scientist in vegetable production systems, and his team initiated simultaneous research trials on both Chinese long and Indian round eggplant during the 2015 growing season.
“We undertook a pan-Canadian farm trial with 22 growers to identify eggplant varieties with good agronomic characteristics that meet consumer demands,” explains Zvalo. “We also investigated whether grafting onto different rootstocks improved disease resistance and yield.”
• Six Chinese and Indian eggplant varieties were evaluated for field production; Asia Beauty, Farmers’ Long and Long Purple hybrids showed the best yield potential.
BIOCONTROL IN PROTECTED CULTURE
A myriad of reasons exist for employing biological controls: ever-changing government regulations, costs of chemicals and applications, pests developing resistance to chemical classes, and public relations benefits of growing “environmentally friendly” products.
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• Nine varieties of eggplant were also investigated for greenhouse production; Long Purple and Purple Comet hybrids showed the most promise.
Grafting onto tolerant tomato rootstock is an effective technique to overcome soilborne disease for field eggplant and to improve vigour and yield for greenhouse eggplant.
Using a Maxifort rootstock, the Vineland team achieved an 84 per cent increase in yield for the Long Purple hybrid in a greenhouse setting. On the other hand, when grafted onto Maxifort rootstock for field production, flowering and fruit set were delayed, which is undesirable.
Farm trials on different rootstocks will be undertaken this year.
“We have also used row covers in field production to obtain an earlier harvest,” says Zvalo. “Modifications of the growing environment through the use of row covers and black plastic mulch are necessary to grow eggplant in Canada.”
As with any new crop, it takes some knowledge and experience to be successful in eggplant production.
Since eggplant is in the Solanaceae (Nightshade) family, insect and disease pressure can be expected to be similar or perhaps slightly higher than other crops in this group (such as tomato and pepper). The major pests are thrips, mites, aphids and whiteflies. Powdery mildew may need to be monitored and treated.
In a high-wire greenhouse, Chinese long eggplant will need to be lowered as the growth rate is high, especially when grafted on Maxifort rootstock.
Following two variety screening trials in a low-wire greenhouse in 2015, the project moved into a newly constructed high-wire greenhouse. Four hybrid varieties of Chinese long and Indian round eggplant were selected and grafted on six different rootstock with the objective to identify the best combination of rootstock and scion (variety) for high yield and quality. This trial is scheduled for 2016 and 2017.
“As new varieties are coming to the market continuously, they are being placed in “an observation block” and screened for desirable traits,” says Zvalo. “Currently we have about a dozen varieties in the observation block.”
This research project is funded by Agriculture and AgriFood Canada’s Agricultural Innovation Program, Growing Forward 2 (GF2), a federal-provincial-territorial initiative and with support from the Ontario Fruit and Vegetable Growers’ Association and participating growers across Canada.
Dr. Viliam Zvalo joined Vineland Research and Innovation Centre in 2014. In his role at Vineland, he investigates field and greenhouse production of world crops and other new crop opportunities for Canadian growers. He brings a wealth of experience after spending 13 years at Perennia Food and Agriculture Inc. in Nova Scotia where he provided support to vegetable producers and managed numerous research projects in new vegetable crop development, cultivar testing, pest management and evaluation of different production systems and methods. He holds a PhD in plant physiology/soil ecology from the Slovak University of Agriculture in Nitra, Slovakia, and an Executive MBA from Saint Mary’s University in Halifax.
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COULD ‘3D’ CHANGE the Way You do Business?
Where we used to be limited in the number of changes we could economically make when a customer requested a custom design, now we can undertake half a dozen iterations if necessary – and that’s only possible because of 3D prototyping.
BY DEREK MOELLER
The path to market for innovative custom containers was once fraught with long production design, expensive mould development and potential miscommunication from flat paper prototypes. Today’s process, however, has streamlined the process for growers, retailers and their container designer partners.
Where we used to be limited in the number of changes we could economically make when a customer requested a custom design to take to market, now we can undertake half
ABOVE
a dozen iterations if necessary – and that’s only possible because of 3D prototyping.
In the past, growers and retailers ordered new container designs based only on computer aided design (CAD) renderings or engineering line drawings. Today, customers can see a physical sample produced right from the drawings, ensuring their vision and the actual product align perfectly.
Without 3D prototyping, it’s difficult to design containers in a way
A 3D printer finishes a pot cover prototype.
PHOTO COURTESY MCCONKEY COMPANY
that relates to the producer’s other pieces of equipment, such as rolling racks or robots. The process of 3D printing takes automation up a level. Trays and pots are built to work with specific products. Rapid prototyping allows for lots of small iterations to get little details exactly right.
And that doesn’t mean only decorative containers. For example, development of an injection-moulded carry tray designed to be used with multiple pot sizes benefits greatly from rapid prototyping. You typically have to have a tray for each pot and manage
return inventory. Designing a product such as this, with so many variables and design angles, would be nearly impossible without rapid prototyping.
One of rapid prototyping’s greatest tenets: let’s stop adapting the square peg for the round hole, when we could be designing the perfect round peg.
HOW DOES 3D PRINTING WORK?
It all starts with a virtual design of the container or tray using CAD. The 3D modeling software then “slices” the
design into any number of horizontal layers (can be hundreds or thousands). The printer creates the object one layer at a time, seamlessly blending layers to create one final prototype.
THE SIX BEST REASONS TO USE 3D PROTOTYPING
1. It avoids expensive mistakes. Rapid prototyping allows you to know exactly what you’re getting. You don’t build out moulds – you save upwards of $40,000 in projects and time.
2. For the first time, growers can create integration automation solutions, designing plastic containers and trays to work with their specific equipment. It allows for a depth of change in the way greenhouse automation is developed.
3. It gives retail buyers a choice. Traditionally, you take what’s on the market and hope the customer likes it. Now we can develop three pots that the retail buyer might like, providing more choices rather than putting all chips in one house. Buyers see all-new, entirely fresh options.
4. It allows the buyer to participate much more in the process and allows them to give infinite input into how they can differentiate from the competition.
5. Products can get to market faster. Faster product creation and approval results in a shorter product development life cycle. The product is on the shelf quicker because you aren’t waiting a month for the mould to be built and rebuilt.
6. It allows for development on any scale. Now available are 3D printers with larger build sizes, allowing design and prototyping of not just scaled down versions but also the full-size product. This makes it easier for growers and buyers to understand how the product will work in the real world.
Fun Fact: 3D printing is rapidly expanding in versatility and can now be used for ceramics, stainless steel, aluminum, glass, even gold.
Even with the amazing advances in design flexibility that we’ve seen recently, this is just the start of 3D prototyping’s potential. The most exciting part will be seeing where the technology takes us –and custom container design – next!
Derek Moeller is president of McConkey Company, a U.S.-based container designer and manufacturer and the first in the horticulture industry to use 3D printing as part of its custom design process.
Root Health is Hidden Wealth
Two vegetable growers in Western Canada offer their insights into what to look for beneath the surface of your growing media, and how it reflects on plant health.
DR. MOHYUDDIN MIRZA
Roots are the foundation of plants we grow in greenhouses. In the February 2013 issue of Greenhouse Canada, I wrote about root health and it’s importance in crop management.
This time I asked two vegetable growers to share with the readers what comes to mind when we talk about rootzone and root health.
Trevor Schriemer of Precision Produce in Otterburne, Man., provided his input. The following are his comments, in quotations.
“Good afternoon Dr. Mirza; here are some of my thoughts regarding rootzone health. It is not exhaustive and you would of course have much to add, but this is what immediately springs to mind.
“Slits in the grow bag should be made near the
bottom so that excess water will not build up and damage roots. Slits should allow almost complete drainage. A large reservoir maintained in the bag reduces the volume of aerated rootzone, which plants need to grow optimally.
“DO (dissolved oxygen) content is important for root health and every grower should know his DO content. If it is too low (below four ppm), then diffused oxygen technology should be employed. High 02 levels in the rootzone reduce the need for expensive applications of pythium-controlling fungicides. Low 02 levels affect ion uptake. This happens at the root hair level, which is stimulated by high 02 levels.
“The need for washed coco is important,
because unwashed coco tends to have consistently higher pH levels that are hard to bring down. Also, washed coco with a prescribed EC is important for the quick penetration of roots from young transplants.
“Pay attention to EC and pH levels in the rootzone every day and specifically when light and VPD levels are highest, especially with the EC.
“Timing of first drain is important, much more important than the per cent of drain over the 24-hour period.
“Media temperature is important to avoid iron deficiencies and reduced growth.”
Schriemer has brought up very important points regarding root health from a practical viewpoint. I am a big fan and promoter of dissolved oxygen in the nutrient solution. Oxygen solubility is strongly dependent on water temperature and decreases with higher temperatures. The higher the dissolved solids, the lower the oxygen levels.
At 4 C water temperature, the
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dissolved oxygen is around eight to nine mg/L (parts per million, ppm). Water is heated for greenhouse irrigation use and at 20 C, the oxygen level drops to around five to six ppm.
I did several actual measurements and found that when the water goes through irrigation pipes, the level at drip line dropped to around four to five ppm. When I measured oxygen levels in leach solution, they ranged from two to three ppm. In one case it was around one ppm. That is almost anaerobic levels. These measurements were done with cucumbers grown in coir growing medium.
Many oxygen meters give a reading on “saturation percentage” rather than mg/L. Eight to nine mg/L is considered close to 100 per cent saturation.
Roots don’t carry out photosynthesis like leaves do and they don’t have stomata either. Roots are very dynamic in the sense that they are constantly developing and growing.
The top photo on page 38 shows a rootzone from a crop of mini cucumbers. The crop was seeded in the middle of September, with harvesting beginning in late October. This photo was taken the third week of January. There are good “feeder” roots visible with root hair. Cucumber plants need to constantly produce new roots and when the roots are bathed with nutrient solution with dissolved oxygen of around eight ppm, then the health is in the “good” range. How best to oxygenate the nutrient solution? Schriemer is using a “diffused oxygen” system where he is able to maintain around eight to nine ppm of dissolved oxygen at a temperature of about 18 C. This particular technology is from Seair. I know there are many other companies in this area of oxygen generation and diffusion, so check them all out. I believe that growers should invest in a reliable oxygen diffusion or enrichment system.
Schriemer noted that the danger of pythium can be reduced if oxygen levels in the rootzone are maintained above four ppm. This root rot fungus likes lower oxygen conditions in the rootzone.
The other inputs that affect rootzone health are also mentioned by Schriemer as well. Note that pH is probably at the top of the list, after oxygen. The pH levels constantly change and fluctuate as the crop is growing. Normally what happens is that as plants are growing and fruiting, the pH will start climbing and moving towards the alkaline side. If you don’t
watch it daily, the pH will suddenly climb to over 6.8 and you will notice when there is iron deficiency in the new growth.
Many growers will drop the feed pH to around 5.1 to 5.4. I believe this is very low pH for the roots and I have seen root tip damage develop quickly. A better approach is to monitor the pH daily, watch for a trend going up or down, and make adjustments before you have to intervene drastically.
ERIC DOEF OF DOEF’S GREENHOUSES
I also asked Eric Doef, at Doef’s Greenhouses in Lacombe, Alta., for his comments. He was one of Greenhouse Canada’s Top 10 Under 40 winners last year.
For starters, he sent me two pictures (Photo 2, page 38, and Photo 3) to illustrate key points.
These are pictures of a mature crop of long English cucumbers. They are grown in plastic buckets with 11L of coir and there are four plants in each bucket. Thus there are 2.75L of coir per plant. This means that roots will be developing in areas where extra water drains out and on the outside of the growing medium. One can see roots on the side and at the base of the bucket.
Doef mentioned the following points in the context of root health. The statements in bold are Doef’s comments and the rest are what I have added.
1. Water quality affects rootzone health. Not only the chemical quality, such as high levels of sodium, will affect the roots. Sodium also destroys the drainage characteristics of the growing medium and thus creates waterlogged conditions.
2. Dissolved oxygen levels have a very big role to play in maintaining proper root health. High organic matter and microbial load can create an “oxygen consumption” situation. That is why growers must know the biochemical oxygen demand (BOD) of their water supply. BOD is the amount of dissolved oxygen needed (i.e. demanded) by aerobic biological organisms to break down organic material present in a given water sample at a certain temperature over a specific time period.
3. Electrical conductivity (EC) – high or low or proper levels – can have a significant effect on root health. High EC under high light conditions can restrict the uptake of water and thus affect the leaf size.
4. Choice of media is also very important for maintaining good root health. It is related to air porosity and water-holding capacity of the growing mixes. Coir is available in different forms – coarse, medium and fine. Growers should choose the growing medium based on the crops they are growing.
5. Sodium levels build up in the growing media over a period of time. Cucumbers are sensitive to higher levels of sodium in the rootzone.
6. Proper irrigation strategies adjusted to light and temperature are very important to maintaining good rootzone health. Growers should pay more attention to vapour pressure deficit (VPD) to start first irrigation, not just at sunrise.
7. Once in a while check the root health by checking for the presence of white absorbing root hair, good root tips and also how roots are distributed in the growing medium. There should be good distribution all across the growing medium.
BEDDING PLANT SEASON
With the bedding plant season upon us, I want to share two pictures (Photo 4 and Photo 5) that indicate issues with root health.
Photo 4 is an example where attention was not paid to pH in the rootzone. These petunias are showing iron deficiency caused by alkaline pH in the rootzone. It will take at least three weeks to turn this crop around and these plants can be un-saleable. Photo 5 is where waterlogged conditions prevailed and roots did not develop properly. Adjust your watering practices to avoid waterlogged situations.
The top growth of the plants can tell us about the health of the roots. Learn to read the plants and make decisions accordingly.
Dr. Mohyuddin Mirza is an industry consultant. He can be contacted at drmirzaconsultants@gmail.com.
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THERE’S NO PLACE like home for urban farming
It’s easy to understand why urban agriculture is booming.
“Consumers associate local produce with improved quality, nutrition and taste, and market research has shown that most consumers are willing to pay at least a 10 per cent premium for these things,” says Sam Wortman, an assistant professor of urban food production at the University of Illinois.
are very successful and some are undergoing substantial expansions, there are also challenges. Wortman lists high capital costs, such as real estate, to be foremost. “Without significant price premiums for the produce grown,” he says, “it would be difficult to justify the added cost of being in the city.”
BY TREENA HEIN
“There is also an increasing sense of community that seems to be compelling consumers to support local businesses.”
However, while many urban farming operations across the world
While Neil Mattson certainly sees the benefits of urban agriculture, including local jobs, he doesn’t see it as something that would ever be able to feed a city population.
Like Wortman, the associate professor of plant science at Cornell University also sees the costs of urban sites as a barrier, and notes
PHOTO COURTESY SMART GREENS
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that they “are not large enough to get the economies of scale you would get in a larger greenhouse facility.”
URBAN AGRICULTURE IN ONTARIO
There are two new and exciting urban greenhouse ventures in Ontario, both deserving winners of the 2015 Premier’s Award for Agri-Food Innovation Excellence.
Aqua Greens – fish and organic greens in Toronto: Craig Petten and Pablo Alvarez have had quite a journey in urban food production so far, and it’s far from over.
After 30 years in the restaurant business, they both enrolled in the three-year “Sustainable Energy and Building Technology” program at Humber College in Toronto.
“We want to make a difference,” Petten says. “Local food was one of the topics that came up in our classes, and during discussions, we said the chives used on potatoes in the steak house where we work come from Texas. We wanted to grow them here. So, for our final project of the program, we planned an aquaponics operation and we’ve never looked back.”
After Humber, the pair studied aquaponics ventures in three U.S. cities, took more courses, and worked on an aquaculture farm. They were also mentored by Aqua Growers, a leading aquaponics company in the U.S.
At their own Aqua Greens operation in Mississauga (for which a new bylaw had to be created), they settled on a University of Virgin Islands design, but had it stacked in four levels. The greens (basil, chives, arugula and lettuce) are organic because Petten says it’s a must for the health of the fish.
In December 2015, Aqua Greens began delivering 12,000
plants and 500 fish (tilapia) a month to upscale downtown restaurants and resorts north of Toronto.
“We worked with chefs to deliver the greens they want,” Petten says. The project began with LEDs before switching to sodium lighting, which was less expensive. However, LEDs will be used “in the scale-up.”
Yes, a major Aqua Greens expansion is coming. Organic certification will be in place soon and the company hopes to work with Whole Foods Market and other retailers in future.
Aqua Greens is also unique in its use of mushrooms for producing CO2. Petten says it’s been worthwhile, but also challenging because although they found mushrooms that like light, the fungi need more humidity than the plants. Petten and Alvarez are currently building a high-humidity room for the mushrooms. They’re also working on extracting the CO2 but leaving the humidity where it is.
Other challenges have included learning about general logistics along with plant nutrient deficiencies and how to counter them. “We’ve also had to change the design here and there,” Petten says, “and it’s been a challenge to get organic certification for both aquaculture and greenhouse production. That’s new in the certification circles.”
They call winning the province’s Premier’s Award “fantastic.”
One of their mentors – Steve Naylor, aquaculture specialist at the Ontario Ministry of Agriculture, Food and Rural Affairs –nominated them.
“So many people have mentored us and made connections and given us so much knowledge. We are very excited about the future.”
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Smart Greens – container greenhouses in Cornwall and beyond: Like Petten and Alvarez, Eric Bergeron and Eric Amyot wanted to “do something better.”
Bergeron was in Internet marketing and Amyot was in retail franchising, and they understand the importance of food security. “There is no need to be importing food from California or Mexico anymore and we wanted to prove that the technology existed to do it and that a solid business model could thrive with
such technology in Canada,” Bergeron says. “We also want to find a way to bring food to regions that can’t grow their own, such as remote regions in the North.”
The Cornwall entrepreneurs began growing greens in a shipping container, with technology purchased from Bostonbased Freight Farms. “We were the first company to try and use this technology in Canada,” Bergeron notes. “It came at a great expense as the electrical components were not up to Canadian standards, so we had a significant
investment in getting everything approved.”
While they do have measures in place to minimize air escape and temperature loss, the two are also working with a company to develop a more robust insulation system for Canadian winters.
A purchased mobile app monitors nearly all of the environmental settings of the growing operation, almost in real time. Bergeron and Amyot also developed a custom app, called “Smart Harvest,” which allows them to manage the business end. “It gives us eight weeks of lead time in terms of knowing our sales output and expected crop yields,” Bergeron explains. “Time and schedule management is a critical part of the success in such a farm system and we felt it was necessary to develop our own app.”
The entrepreneurs have found the Cornwall community to be quite supportive. They deliver kale and lettuce on foot to about 10 downtown restaurants, and in January they started a small direct sales contract program for individual consumers because demand has been so high.
Electricity rates in Cornwall are quite good and they use LED lights.
Smart Greens has plans to set up 25 more units in Eastern Ontario over the next few years, but is not committed to just shipping containers. “The technology out there is moving forward so fast that it would be detrimental to simply stick with one technology or ag-tech provider,” Bergeron says.
They recently signed a deal with ZipGrow in Wyoming that will allow them to set up operations inside buildings, and are now selling made-inCanada ZipGrow products through a side venture called Modular Farms.
They are also actively looking for like-minded people to operate their own farms and work within the Smart Greens brand anywhere in Canada.
Of winning the Premier’s Award, Bergeron says it’s always nice to be recognized, “especially for innovation. It was also pretty cool to see what else people are doing to innovate agriculture in Ontario. It tells me that there is an appreciation for innovation in this sector and that is great, because our entire food system needs to evolve rather quickly to a more food secure and local supply.”
View the web version of this story at greenhousecanada.com for photos.
Treena Hein is a freelance writer in Ontario.
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Growers weigh in on screening benefits
Climate here is a funny old thing, and less predictable than it used to be. But we still at least expect January through March to be colder than summer and plan accordingly. So it is that many greenhouse producers are routinely using screens to reduce energy costs. Starting as a response to rapidly increasing energy costs, some producers already have a decade’s worth of experience. So, let’s see what growers have learned. Remember though, this definitely has a West Coast flavour!–
Do screens give the energy savings hoped for?
Tomato grower Gord Yakel, of Delta View Farms, says that “numbers said we’d save 30 to 40 per cent energy costs. Of course we have to balance this with light being blocked by closed screens, and that as the screen gets dirty it blocks more of this light.”
Laura Bryce of Village Farms, Delta, says, “Over the last 15 years, our average gas usage is about 25 per cent less when using screens.” But “a bit of that is because we’re more conscious of not putting in pipe temperatures over 60 C ever, where 10 years ago people could be using pipe of 75 C. Village Farms typically runs the screen from planting (Week 50) to Week 20, and then again in Weeks 38-48, averaging about 1,500 screening hours per year.”
is, don’t gap if you’re creating cold strips in the greenhouse.”
Yakel agrees: “One really nice aspect of screens is being able to vent above it – especially when it’s cold outside. The screen prevents cold air dropping onto plants, but venting helps to create great climate/humidity levels that plants love. I’ve learned to use it cautiously. I mean there are days where it’s a no-brainer. On cold, rainy days when nothing is happening, keep it closed and save energy. But I’m quick to open the screen when outside temps are above 9 to 10 C. And I open it quickly as light intensity increases to utilize as much light as possible.”
He also adds that “when the vents are open in summer months, dust and dirt accumulates on the screen (even though it’s open and compressed against the truss), and figuring the best way to clean it is a challenge.”
Growers have to decide on whether to gap or not to gap.
Do screens bring other benefits? Indeed they do. “Some growers use energy screens for shade in summer weather extremes to reduce crop stress and keep plant temperatures at achievable targets,” Bryce says.
At Delta View, Yakel says “getting the crop in the first week of January, young plants can get 600 joules. To utilize all this energy, I may need to run high 24-hour temperatures and the screen allows me to achieve this without raging hot pipes. I can get away with 50 to 55 C night pipes, whereas without a screen the pipes would be 70 C+ and those really hot pipes are a vegetative influence on the crop.”
Do screens bring any challenges? At Village, they add at least another weather-dependent decision to the day! Also, Bryce says growers have to decide on whether “to gap or not to gap? Some growers gap the screen to reduce air temperature, some prefer to vent above the screen. The point
What else have growers learned? Yakel advises that “in the beginning we were so focussed on saving energy that we actually over used it (keeping it closed for too many hours each day). We created some pretty humid climates, and saw a lot of botrytis that first year. We did come in under energy budget though,” he chuckles. “It’s crucial to be aware of how it’s affecting greenhouse humidity. If it’s too humid, you’re using it wrong: put a crack in it (maybe two per cent crack), open your windows, adjust pipes, or stop using it!”
Yakel also stresses the importance of good installation using quality materials. “Proper installation is really important in how well the screen performs. When it closes, it should be sealed tightly against the trusses and edges. Gaps create areas where cold air spills down onto plants, leading to unevenness.”
Would you do it again? “Over the years, it’s been a very useful tool for Delta View,” Yakel says. “When used properly, screens really can help create a nicely balanced crop.” So, I guess that’s a “yes!”
We could chat about screens and bees and fires and yield, and… but perhaps we’ll revisit those in another 10 years.
Gary Jones is co-chair of horticulture at Kwantlen Polytechnic University. He serves on several industry committees and welcomes comments at Gary.Jones@kpu.ca.
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