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Education takes centre stage

Greenhouse technology firms join forces to support growers at ACT grower summits

June 10, 2024  By Kerstin Poehlemann

Amos Bassi (right) with Philips LED Lighting and Andrew Lee (left) with Grodan presented their research and findings on energy efficient year-round tomato production with 40 per cent less heat input.

Considering how many aspects go into growing a healthy and profitable crop, the need to stay on top of technological developments is ever-present for growers, especially in Controlled Environment Agriculture (CEA), where conditions need to be ideal at all times. Fortunately, education opportunities are available, such as the Grower Summits organized by the ACT group (Advancing Cultivation Technology). Well over 100 growers convened in March in Leamington (and another group of nearly 100 in late April in Langley, B.C.) to learn about aspects such as screening technologies, energy-efficient tomato production, crop diversification, and more. Here’s a look at some of the information presented, latest research results, and takeaway lessons learned. 

The event kicked off with a presentation by Jan Westra, Strategic Business Developer at Priva, on the power of predictive growing in CEA. Greenhouse technology has come a long way from original glass or poly structures and hand watering to today’s high-tech operations. Westra sees a strong future in predictive growing, where simulated computer models are used to predict how changes in growing conditions and inputs affect crop performance, yield, and profitability. Known as “digital twin,” the computer model replicates current growing conditions in the greenhouse, which can then be manipulated in myriad ways to predict the ways climate- and other input changes can have on the crops. Since the amount of information processed is massive, the use of AI (artificial intelligence) helps process and calculate the information and provide a regular feedback loop. This will allow growers to optimize growing conditions in a proactive way, rather than reactive if the crops don’t perform as desired. It will also allow growers to control and integrate more factors than in the past.  

Next, the grower summit addressed energy efficient year-round tomato production with significantly less heat input, where Amos Bassi, Plant Specialist for Philips Horticulture LED Solutions, and Andrew Lee, Global Technical Knowledge Manager for Grodan, presented their latest research. The trial – conducted at Botany’s trial station in The Netherlands, and currently at the end of year one of three – aims to demonstrate the opportunities for realizing low heat input in a full LED tomato cultivation by aligning strategies for climate, irrigation, and nutrient management. Typically, under low heat input growing conditions, the plants’ transpiration is reduced, which leads to lower nutrient uptake and therefore reduced yield. The trial is aimed at ways to increase nutrient uptake and subsequently yield, and has shown very promising results to date.


It’s important to note that the light recipe being used was specifically developed after years of research and trialing by Philips horticulture LED team. The crop is lit with dimmable Philips toplighting compact in the spectrum of deep red white low blue (DWRLB), which offers an efficacy of 3.4 µmol/J.

By connecting the Philips GrowWise Control System to the climate computer, the LED lights were set to dim according to forecasted natural light levels. This integration of three technologies – LED lighting, Philips GrowWise, and the climate computer – ensured the total light level did not exceed the Daily Light Integral (DLI) of 22 mol/m2w/day. 

One part of the trial is aimed at adjusting the nutrient strategy to optimize nutrient uptake under low heat conditions. The researchers used chloride to replace nitrate in the adjusted strategy, as it is better than sulphate for supporting total nutrient uptake. In doing so, the following differences in crop development were noted: smaller leaves and a lower Leaf Area Index (LAI); higher dry matter percentage, therefore, higher brix while maintaining the correct uptake ratio of individual nutrient elements.

Another key element of the trial was to implement active dehumidification allowing for more screen usage, which results in greater air movement and therefore, increased movement of nutrients and transpiration through the plant. Therefore, positively influencing energy savings. 

While the trial was aimed at realizing a 40 per cent reduction in energy costs (heat, lighting, dehumidification), the actual results came in even better at a savings of more than 50 per cent The researchers will continue the trial for two more years to further fine-tune strategies and results. 

The grower summit continued with a session on Leveraging Climate Screens for Plant Health and Energy Conservation through Advanced Screening Strategies, presented by Paul Arena and Pieter Mol, Greenhouse Climate Consultants for Svensson. Choosing the right screen is affected by many factors, including crop type, crop needs, growing strategy and objectives, location, outside climate data (sun radiation, temperatures, humidity), greenhouse type and cover, and greenhouse equipment. The speakers first addressed the potential for energy savings by using double screens. By double-screening, growers can realize energy savings of up to 63 per cent, versus up to 47 per cent with a typical single screen. But not all greenhouse structures have enough room for double-screening. In this case, the use of what’s referred to as “cavity screens” is beneficial, where two layers are installed in one system with a two- to five-inch gap between the two layers, which acts as an insulating air pocket. Cavity screen systems provide about the same energy savings as a double screen system, with their only caveat being less flexibility to control internal climates. 

Aside from energy savings, screens are also a good option for humidity and moisture control, because the fabric can absorb moisture from the air below the screen and releases it above, therefore improving crop conditions. Arena pointed out that it is important to have the measurement device above the screen. 

Arena and Mol continued their presentation with explaining the importance of light diffusion and the use of screens for this purpose. Diffuse light – versus direct light – leads to higher production because of better spread of the light over the whole plant, including the lower leaves, which increases photosynthesis. Diffuse light also leads to lower and more uniform crop temperatures. While diffuse glass is somewhat effective, using screens provides much more flexibility. Screens give control on light levels when needed (spring, summer, autumn), improve plant-head – truss temperature (2-4 oC lower), increase photosynthesis levels, improve greenhouse climate (RH – AH), and overall lead to stronger plants and less disease. 

The presentation concluded with information on the benefits of closing energy screens at night, which helps maintain a warmer plant temperature, resulting in less condensation on the plants (therefore less disease pressure) and more efficient calcium uptake (calcium deficiency can lead to blossom end rot). 

The last session of the day took a step away from technology and educated growers on Understanding Environmental Farm Plans, Biosecurity Plans and Funding for Greenhouse Operations, presented by Margaret May with the Ontario Crop & Soil Improvement Association (OSCIA). OSCIA’s vision is farmers actively seeking, testing and adopting optimal farm production and stewardship practices, and delivers several cost-share funding programs that support Ontario’s farmers in implementing best management and sustainability practices on their farms. The Environmental Farm Plan (EFP) began in 1993 as a pilot program and has since grown to over 35,000 participants and has been adopted across Canada and around the world. The EFP is a self-assessment program that will help growers see their farm in a new way. Through the EFP process growers will increase their awareness of environmental strengths and identify areas of concern; set realistic action plans with timelines to reduce environmental risks; improve productivity and profitability; and learn how the EFP may be used in conjunction with cost-share programs to begin implementing action plans. May stressed that this is a self-assessment tool and that all reviews are confidential. “Nobody can make you do anything,” as she put it. 

Next, May presented information about biosecurity workshops and webinars offered by OSCIA that are designed to teach growers about on-farm biosecurity. Commodity-specific opportunities are offered as a one-day, in-person workshop, or as two, 2-hour webinars, where growers learn the benefits of having an on-farm biosecurity program and identify current practices that could be improved or actions that can be taken to reduce risks. Growers will then work with a technical expert, such as a vet or CCA, to help identify key practices to enhance biosecurity measures on-farm, as well as reduce health and safety risks for employees and family. 

Additional cost-share programs that May detailed include the Ontario On-Farm Climate Action Fund (OFCAF), the Species at Risk Partnerships on Agricultural Lands (SARPAL), the Sustainable Canadian Agricultural Partnership (Sustainable CAP), the Resilient Agricultural Landscape Program (RALP), and the Grow Ontario Market Initiative. Significant cost-share funding is available for implementing any of these programs. Growers can find details at 

The grower summit concluded with a panel discussion featuring Andrew Lee (Grodan), Amos Bassi (Philips LED Lighting), Jan Westra (Priva), Pieter Mol (Svensson) and Laust Dam (crop consultant). Much has yet to be done to communicate CEA food production’s significant technological advances to the end consumer. Today’s production methods represent tremendous energy savings compared to the production methods from years or decades ago, yet, our industry hasn’t done enough to communicate our sustainability efforts to the public. Of course, the continuous need for optimizing all aspects of growing is fueled by much more than public image. Input costs (including labor, energy costs, materials, etc.) are expected to continue to rise, as are demands for reliably high crop quality. In order to meet these needs, the panelists predict an increase in autonomous growing. Lee pointed to the importance of investment in knowledge today, which will lead to greater innovation and energy savings tomorrow. The growers in attendance certainly recognized this need when they decided to dedicate their time to an educational event, as did the organizing companies, which are dedicated to continue making knowledge sharing and grower education a priority.  

About ACT: ACT is a collaboration of four horticulture industry-leading providers: Grodan, Philips LED lighting, Priva, and Svensson. The group partners in North America to bring together growers by offering education on the latest cutting-edge technologies and best practices, and provide networking opportunities. For more information, please visit, or contact one of the organizing companies. 

 Kerstin Poehlmann is president of Pen & Petal, Inc., a marketing communications firm for the green industry. She can be reached at

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