LED Growers Guide. LEARN HOW TO GROW WITH LEDs. for VINE CROPS. The Industry s Only How-To Guide for Professional LED Growers.

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1 LEARN HOW TO GROW WITH LEDs The Industry s Only How-To Guide for Professional LED Growers LED Growers Guide for VINE CROPS 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 1

2 About Guide LumiGrow, a smart horticultural lighting company, has developed this LED Growers Guide to instruct growers how to use LED lighting strategies to maximize profits, boost yields, increase crop quality, and elicit desired plant characteristics. All recommendations herein are based on rigorous commercial and research trials. LumiGrow PhDs and Plant Scientists perform research trials in collaboration with some of North America s leading commercial and research institutions, and utilize this knowledgebase to develop the industry s leading horticultural lighting strategies. The LumiGrow Plant Research Group also retains a library of outside scientific studies conducted at leading universities, some of which are referenced in this guide. Notes on Vine Crops Vine Crops represent an economically important segment of greenhouse-produced crops, with the top three producers being tomatoes, cucumbers, and sweet peppers. These top three producers are grown and behave similarly in a greenhouse setting. All three are grown in high-wire trellis systems to ensure the highest yield per plant density. Supplemental lighting is of high importance to growers due to the high light needs of their crops. LED technology provides a multi-use utility for these growers. First, the luminaires provide needed light for healthy crop production in the dark seasons, and second, they allow for the control of desired crop characteristics. Of special interest to vine crop growers choosing to use LEDs is the ability to increase yield, influence growth rate, and extend crop life. Research has already shown that it is possible to use LEDs to control tomato growth at every growth stage. Cucumbers have proven to be highly sensitive to light, and can be readily manipulated using red and blue wavelengths as well. LumiGrow has also conducted recent exploration into the feasibility of using LEDs for sweet pepper production. Early work has already shown that peppers are just as receptive to spectrum as tomatoes and cucumbers. The LumiGrow Plant Research Group makes recommendations based on our prior experience, our expert horticultural resources, leading scholastic research, and from ongoing findings by our in-house research and commercial partnerships. In this section, we present a glimpse into current research relevant to vine crops, from this research we distill conclusions and recommendations. Contact a LumiGrow Lighting Specialist at (800) ; lighting@lumigrow.com; or visit our website for additional information at 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 2

3 Table of Contents About the Authors... 4 LED Lighting for Tomato Crops Lighting Requirements for Tomatoes... 6 Tomato Lighting Recommendations... 7 Light Quality and Tomato Growth LED Lighting for Tomato Seedlings LED Lighting for Tomato Grafting LED Lighting for Tomato Production LumiGrow In-House Tomato Research The Future of Tomato Spectral Science LED Lighting for Cucumber Crops Lighting Requirements for Cucumbers Cucumber Lighting Recommendations Light Quality and Cucumber Growth LED Lighting for Cucumber Seedlings LED Lighting for Cucumber Production LumiGrow In-House Cucumber Research The Future of Cucumber Spectral Science LED Lighting for Pepper Crops Lighting Requirements for Peppers Pepper Lighting Recommendations Light Quality and Pepper Growth LED Lighting for Pepper Seedlings LED Lighting for Pepper Grafting LED Lighting for Pepper Production LumiGrow In-House Pepper Research The Future of Pepper Spectral Science LumiGrow Pro Series E LEDs LumiGrow smartpar TM Software LumiGrow Support References LumiGrow Inc. LED Growers Guide - Vine Crops 3

4 About the Authors Melanie Yelton, PhD. Vice President of Research at LumiGrow, Ms. Yelton leads the horticultural lighting industry forward in discovering new ways to elicit desirable crop characteristics through the use of LEDs. Prior to joining LumiGrow, Melanie served as a lecturer and research scientist at Stanford University. Melanie completed a National Institutes of Health postdoctoral fellowship in microbial signaling between Rhizobium and alfalfa at Stanford University. She earned a Ph.D. in molecular biology from the University of California, Davis, where her work focused on plant pathogens. She holds an M.S. in the biochemistry of photosynthesis from the University of South Carolina, Columbia and a B.S. in biology from Virginia Tech. The recipient of numerous academic awards and accolades, Melanie is a patent holder for her work involving filamentous fungus such as Aspergillus strains. Earlier in her career, she served as director of sequencing at the Stanford DNA Sequence and Technology Center, a division of the Human Genome Project. Jake Holley, MS. Senior Research Associate at LumiGrow, Mr. Holley has been conducting greenhouse research since 2011, and earned his M.S. in Horticulture and Agronomy from UC Davis in At UC Davis, his research focused on light spectrum effects, with specialization on the flowering of Phalaenopsis orchids. Jake began instructing courses on ornamental and vegetable production in controlled environments at UC Davis, as well as assisting greenhouse related courses. Jake offers extensive experience providing consultation for a broad range of crops, from ornamental potted plants, to hydroponic tomatoes. Brian Poel, MS. Plant Science Specialist at LumiGrow, Mr. Poel has over a decade of horticultural research experience, with a focus on controlled-environment production. After three years of greenhouse vegetable seed research and development, Brian received his M.S. in Horticulture from Michigan State University where he compared the performance of LEDs and HPS lamps for supplemental lighting of annual bedding plant seedlings. He also holds a B.S. in Plant Biology from the University of Guelph where he focused on integrated pest management and novel control methods in horticulture. Previously, Brian was integral to research initiatives working for major Agribusiness companies such as Bayer CropScience and Syngenta. Mr. Poel earned a National Science and Engineering Council Research Award for three years in a row from 07 to 09. Rachel Schuster, BS. Research Associate at LumiGrow, Ms. Schuster graduated from San Francisco State University in 2014 with a B.S. in Biology with a concentration in Botany, and received a Field Ecology certificate in 2016 from Sacramento City College. Rachel has worked with LumiGrow since 2014, specializing in spectral science and the interactions between LED light and plants. She has developed and assisted numerous large-scale LED spectral trials, researching a variety of crops including lettuce, tomato, cucumbers, and herbs LumiGrow Inc. LED Growers Guide - Vine Crops 4

5 WHAT YOU WILL LEARN IN THIS SECTION: Lighting requirements for tomatoes How light intensity, quality, and photoperiod affect tomato crops How to use light to control your tomato production across growth stages What leading researchers are learning about light s interaction with tomatoes Lighting Tomatoes Truly a fruit of much labor, the greenhouse tomato takes considerable commitment, effort, and skill to produce. The time and effort needed to raise greenhouse tomatoes is often closer related to that of a dairy or poultry operation due to the continuous daily responsibilities the plant requires. Tomatoes still prove to be well worth the work, and continue to be an important crop for both horticulturalists and consumers. According to a 2015 study by the Agricultural Marketing Resource Center (AgMRC), tomatoes were found to be the second most consumed vegetable in the U.S. behind potatoes. Greenhouse tomato acreage in the United States has been on the rise since the 1990s, with consumer demand for year-round high-quality vegetables pushing this expansion. Consumers have proven willing to pay for fruit that is more uniform in size and shape. Modern breeding practices have also led to the development of more disease resistant cultivars. The controllability and marketability of tomatoes makes greenhouse production of tomatoes attractive to growers. Light has proven to be exceptionally important for tomato crops. Being high light plants, tomatoes need plenty of supplemental light to maximize production. LEDs provide additional benefit due to the ability to adjust and customize the light spectrum being emitted LumiGrow Inc. LED Growers Guide - Vine Crops 5

6 LumiGrow LED Lighting Card Lighting Requirements for Tomatoes SEEDLING RECOMMENDATIONS GRAFTING RECOMMENDATIONS PRODUCTION RECOMMENDATIONS Daily Light Integral (DLI) - sunlight + supplemental measured in mol m -2 d-1 Photoperiod based on 24-hour period Temperature (Day) Farenheit and Celsius C F Variable C F Temperature (Night) Farenheit and Celsius C F Variable C F Tomato Crop Schedule Sow Stage days Transplant Stage 4-6 weeks Harvest Stage 3-8 months 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 6

7 Tomato Lighting Recommendations Although traditionally grown in sunny regions, tomatoes often experience limitations to the amount of light they receive due to variable climate conditions. Consequently, tomato growers often fail to meet their crops lighting requirements, especially during early fruit production. In general, a 1% increase in DLI results in a 1% increase in yield for tomato plants As a high light plant, tomatoes experience more growth as the amount of light they receive increases. For this reason, light is generally the limiting factor for plant growth. Lighting requirements will vary based on the crops growth stage. For tomato seedlings, a DLI of 13 to 16 mol m -2 d-1 is recommended. Production tomatoes require a DLI of 20 to 50 mol m -2 d-1. LumiGrow recommends a photoperiod of 18 to 20 hours for best growth. It is not recommended to light plants for 24 hours, as this negatively impacts plant health. For DLIs under 20, fruit set decreases and ripening becomes blotchy. Fruit production can be improved by increasing the DLI using supplemental lighting. DLI can be increased by either extending the photoperiod or increasing the intensity (or photosynthetic photon flux, PPF) while maintaining the photoperiod. In general, a 1% increase in DLI results in a 1% increase in yield. Light Quality and Tomato Growth Light quality has been proven to have significant effects on tomato plant growth and morphology. LumiGrow s Smart Horticultural Lighting is designed to give growers a professional-grade tool for controlling these effects by finely tuning plant development. By adjusting LEDs to emit specific wavelengths of light, growers can achieve desired plant responses at various phases of growth. When using light quality as a tool for controlling tomato growth, it is important to establish production requirements, and use light accordingly to achieve specific growth goals. Much like any other production variable used for agriculture, light should be adjusted, measured, and maximized to achieve better growth. When developing a professional lighting strategy, it is beneficial to take into consideration the profound effects that red and blue light have on plant development. Red light can be used to increase stem elongation and accelerate flowering. Blue light has proven important for improving tomato plant morphology, photosynthesis, and overall plant health. Red light alone can be used to grow tomato seedlings, but a lack of blue light can have adverse effects on plant morphology, such as a reduced chloroplast development, thin leaves, and the formation of leaf 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 7

8 intumescences. Blue light combined with red light suppresses stem elongation, and increases plant biomass and fruit production. LumiGrow has determined common trends when using adjustable light spectra for specific growth stages, as seen through rigorous production trials. A compact plant can be achieved by increasing blue light which may be desirable for standard transplants. A stretched plant, preferred for grafting purposes, can be achieved using higher ratios of red light. Increases in yield can be achieved by increasing the ratio of blue to red light. Although we ve found these trends to be true in most cases, lighting requirements will vary based on location, greenhouse material, production style, and cultivar. When comparing LED-lit tomato crops to HPS-lit or un-lit systems, there are also baseline differences in plant morphology and characteristics that are important to factor in when measuring the success of your lighting solution. Both in greenhouse and sole-source environments, it is common to see leaves become thicker and darker in color with increased blue light from LEDs. Trials done by the LumiGrow Plant Research Group have also seen differences in plant growth rate as lighting factors are adjusted. These common morphological differences in LED-grown vs. HPS-grown plants are due to differences in supplemental light spectrum. Changes in morphology can often be attributed to the addition of narrow bands of red and blue light to the plants. Red and blue light influence plant growth and overall health, and have positive impact on photosynthetic growth. Supplemental lighting that s applied in the red and blue portions of the spectrum provides more light that is optimal for photosynthesis, having the potential to exhibit baseline differences in morphology when compared to broad spectral distribution common to HPS lighting. As plants mature and enter reproductive stages, their lighting demands may continue to change. Growers seeking to maximize production must treat light as a powerful variable, and adjust accordingly to meet their plants changing demands. LED Lighting By Growth Stage The LumiGrow Research Group presents strategies based on academic research an in-house and commercial trials. Explore how light affects tomato plants differently through their primary growth stages, from seedlings, to plant grafting, to production LumiGrow Inc. LED Growers Guide - Vine Crops 8

9 LED Lighting for Tomato Seedlings Tomato seedlings have different lighting requirements than plants in production. Seedlings -1 should be uniform in size, with well-developed leaves and roots. A DLI of 13 to 16 mol m-2 d has been proven sufficient for tomato seedling growth. Ultimately, light quality requirements are dependent on the intended use. Morphological preferences for scions, rootstock, or non-grafted production seedlings may vary. Extensive research has proven that supplemental light is beneficial for tomato seedlings in a greenhouse setting. In a 2015 at Purdue University study (Research Study 1.1), it was reported that tomato seedlings grown under supplemental light had thicker hypocotyls, up to 55% larger leaves, and up to 50% more shoot dry weight compared to those grown under ambient light alone. The effects of blue supplemental light on tomato seedlings is also noted in the study, which is of interest to growers intending to use adjustable spectrum strategies to affect plant growth. Across various blue to red LED light ratios, the highest ratio of blue to red light reduced hypocotyl elongation most significantly. 1.1 Research Study Supplemental Blue Light Improves Tomato Seedling Quality Researchers at Purdue University have demonstrated that supplemental lighting can be used to reduced hypocotyl elongation in tomato seedlings. Six different varieties of tomatoes were grown in a greenhouse environment, under four supplemental lighting treatments, one from a 100-W HPS lamp, three from LEDs with varying ratios of red to blue (100:0, 95:5, 80:20) and an ambient light control with no supplemental lighting. Each supplemental lighting treatment was delivered at 61 μmol m -2 s -1 for 23 hours per day. Results Tomato seedlings grown under supplemental lighting that included blue light had thicker hypocotyls with larger leaves and more dry weight compared to those grown under the red light alone treatment. The results of this study are promising because they show the application of adjustable spectrum lighting for directing tomato seedling growth in the greenhouse. Gomez, C. & Mitchell, C Growth response of tomato seedlings to different spectra of supplemental lighting. HortScience 50(1) LumiGrow Inc. LED Growers Guide - Vine Crops 9

10 Similar experiments repeated by the LumiGrow Plant Research Group have found comparable findings, that higher ratios of blue light produce a shorter, more compact, and more robust tomato plant. Growers that use LumiGrow LEDs are finding innovative ways to use blue light in seedling production to increase quality, and reduce operational costs. Some growers have seen benefit in using blue light to elicit compactness and rigor for their tomato plants that result in savings on shipping costs. Innovative growers have been able to increase the number of plants they can fit on a pallet and subsequently reduce their shipping costs by using adjustable spectrum strategies. LED Lighting for Tomato Grafting Light control for seedling production has proven especially important for grafted tomatoes. When growing plants for grafting it is important that rootstock and scions be uniform in growth. A DLI of 5 to 7 mol m -2 d-1 has been proven ideal for tomato grafting. LED lights can be used at the same intensity as fluorescents for healing grafted tomatoes, to produce compact plants with uniform height. Healing is the most critical step in tomato grafting. It is important to provide grafted seedling with an optimal environment to ensure graft take. Cool white fluorescent lighting is currently the most used light for healing grafted plants, but much like how LEDs are replacing HPS lights due to limited controllability, energy inefficiency, and broad spectrum, LEDs are replacing fluorescent lighting for the same reasons. Research done in conjunction with researchers at North Carolina State University showed the use of LEDs for the post-graft healing stage. They compared seedlings grown in healing chambers under conventional cool white fluorescents to seedlings grown under LEDs. The grafting research (Research Study 1.2) demonstrated the use of LEDs in the place of fluorescent lighting for tomato graft healing. LED lights can be used at the same intensity as fluorescents for healing to produce compact plants with uniform height LumiGrow Inc. LED Growers Guide - Vine Crops 10

11 1.2 Research Study Using LEDs for Tomato Grafting Researchers from North Carolina State University investigated the use of LEDs for tomato graft healing in chambers. They grew rootstock (cv. Maxifort) and scion (cv. Trust) in the greenhouse prior to grafting. After grafting, plants were put in healing chambers under six different light treatments. Light treatments consisted of cool white fluorescents (100 μmol m -2 s -1 or 75 μmol m -2 s -1 ) or varying ratios of blue, white, and red LEDs (4B:5G:89R, 30B:2G:68R, 50B:50R, and 76B:24R) at 75 μmol m - 2 s -1. Results Plants grown under the 4B:5G:89R, 50B:50R and 76B:24R had similar height, biomass, and plant compactness compared to cool white fluorescent at 100 mol m -2 d -1. Results showed that LED lighting can heal grafted tomatoes as well as cool white fluorescent lighting in a sole-source environment. Byrtus, J., Collado, C., Hernandez, R Light emitting diodes as an alternative to cool white fluorescents for healing of grafted tomato transplants ASHS Annual Conference. LED Lighting for Tomato Production Supplemental lighting is especially important for off-season tomato production and allows growers to increase the DLI to summer-like conditions above 20 mol m -2 d-1. The role of red to blue spectral ratios have also proven beneficial for tomato production, with higher ratios of blue to red light being shown to promote flowering and fruiting, as well as higher ratios of fruit biomass produced for an overall more marketable fruit. Researchers at McGill University (Research Study 1.3) found similar results to those observed in various LumiGrow trials, and saw LED lighting to consistently out-perform HPS-grown plants. They studied the effects of light intensity and spectrum on tomato production. Their results show that increased light intensity coupled with a 5:1 ratio of red to blue light produced the highest yields. Past studies have also shown that LEDs can be used successfully for vegetable production and produce similar or better results than HPS. For example, researchers from Purdue found that fruit quality was unaffected by supplemental light, neither HPS nor LED. Additionally, a tester panel did not discern differences between fruits. It s also important to note that these studies have shown that plant responses are species and even cultivar specific, stressing the importance of testing your cultivars when adjusting any major growth variable. Based on the findings of prior academic research, LumiGrow recommends supplemental lighting intensities over 100 μmol m -2 s-1 with a spectral ratio high in blue light LumiGrow Inc. LED Growers Guide - Vine Crops 11

12 LumiGrow continues to conduct significant research on light for tomato production in collaboration with our commercial tomato partners, exploring the interactions between LED spectra, yield, and fruit quality. Recent research at LumiGrow continues to show that tomato plants grown under LED yield sooner and for a longer time than those grown under HPS lamps. Additionally, tomato vines were observed to last longer and were considerably more vigorous in LED treatments compared to HPS. 1.3 Research Study Blue and Red Spectrum LEDs Superior to HPS on for Greenhouse Tomato Production Average Number of Fruit :1 High 10:1 High 19:1 High HPS Control Fig. 1, from Deram et al., Average number of fruit per plant per light treatment. The data were separated into three categories by yield performance. Graphical estimation illustrates LED (pink), HPS (yellow), and Control (orange). An experiment at McGill University investigated the role of red to blue ratios for greenhouse tomato production. Researchers applied supplemental lighting treatments from LEDs at 3 different red:blue ratios (5:1,10:1, and 19:1) and at 3 intensities (100 μmol m -2 s -1, 115 μmol m -2 s -1, 135 μmol m -2 s -1 ) as well as a HPS treatment applied at 135 μmol m -2 s -1 and a control treatment of no supplemental light. Results All supplemental lighting treatments, regardless of red:blue ratio or intensity out-yielded the control (Fig. 1.). Specifically looking at the 135 μmol m -2 s -1 treatments, plants under each LED treatment out-yielded those under the HPS treatment. Fruit production was greatest under the 5:1 light treatment at all three light levels. The 5:1 ratio produced a greater number of fruit, with a higher weight, and with the greatest fruit mass to plant biomass. This study demonstrates that blue light promotes flowering and fruiting and superior fruit quality. The LED-grown plants consistently out-performed the HPS grown plants. The authors concluded with using LEDs for supplemental lighting can be considered an improvement over traditional HPS lighting for greenhouses. Deram, M., M. G. Lefsrud and V. Orsat Supplemental lighting orientation and red-to-blue ratio of light-emitting diodes for greenhouse tomato production. HortScience 49(4) LumiGrow Inc. LED Growers Guide - Vine Crops 12

13 LumiGrow In-House Research Patterson Greenhouses - Tomatoes Patterson Greenhouses is a successful vine crop grower located in Broadway, North Carolina. In business since 1998, the company is known for its pesticide-free tomatoes. The LumiGrow Plant Research Group worked in partnership with Patterson Greenhouses, to trial winter tomato production in their central North Carolina greenhouse to compare tomato production in non-lit and LED-lit bays. The greenhouse was divided into 3 bays: a non-lit bay, a central guard bay, and an LED-lit bay. Seeds were propagated under sole-source LED light for 8 weeks, then transplanted to the greenhouse. As this experiment was performed in a commercial production facility, bias was given to the non-lit and guard bays by placing the more developed seedlings in these bays four days before placing the lesser seedlings in the LED-lit bays. However, after three weeks under the LED light, the lesser seedlings were more vigorous than the non-lit plants. The first harvest in the LED-lit bay was nine days earlier than the non-lit bay. At final harvest, the LED-lit bay had a yield increase of 15% to 30% depending on the available ambient light. The LED-lit vines were also longer, and had a greater stem diameter. Compared to the non-lit plants, the LED-lit plants were superior in overall growth and production. Key Findings LED-lit plants were transplanted 4 days later and had a first harvest date 9 days earlier than non-lit controls. LED-lit plants had a yield increase of 30%. LED-lit plants were more vigorous, showing an increase in vine length, stem diameter, and a 50% increase in vine weight LumiGrow Inc. LED Growers Guide - Vine Crops 13

14 The Future of Tomato Spectral Science As the knowledge-base of spectral science grows into the future, tomatoes will continue to play an important role in understanding the ways in which plants use light. Research has already shown that tomatoes are receptive and sensitive to changes in light spectrum, and this sensitivity to spectrum is already being manipulated by some of the world s most efficient growers. Harnessing light quality as a growth variable to achieve more rigorous quality and production targets that positively affect a grower s bottom-line is the most recent proven method for maximizing crop production efficiency. Commercial viability of LED-grown tomatoes has far surpassed the question of whether it s possible to grow healthy and productive plants with LEDs. Growers are now maximizing their profits by using adjustable spectrum technology for better control over plant characteristics, such as growth rate, flowering times, yield cycles, flavor, nutrition, and in some cases to combat plant disease. Innovative lighting methods have been applied to boost fruit quality, increase production efficiency, streamline supply-chain processes, and reduce operational costs in addition to dramatic energy-savings. LumiGrow continues to research spectral science for tomatoes, specifically exploring the ways in which specific wavelengths can further boost crop yield and increase commercial quality. WHAT TOMATO GROWERS ARE ACHIEVING W/ LEDS Boost fruit quality by delivering more red and blue light to your crops, while using adjustable lighting to manipulate crop growth Increase production efficiency by decreasing time-to-flower, and managing growth stages effectively with light Streamline supply-chain processes by using adjustable-spectrum to create compact plants that save on shipping costs Reduce operational costs with dramatic energy-savings and monitor electricityusage and performance w/ smartpar 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 14

15 WHAT YOU WILL LEARN IN THIS SECTION: Lighting requirements for cucumbers How light intensity, quality, and photoperiod affect cucumber crops How to use light to control your cucumber production across growth stages What leading researchers are learning about light s interaction with cucumbers Lighting Cucumbers Cucumbers are the second most economically important greenhouse vegetable in the United States, with the US being ranked fourth in global cucumber production. Cucumbers are a warm season crop that requires plenty of sunlight. There are three distinct types of cucumbers: seedless, seeded, and mini. Traditional greenhouse cucumber varieties include the standard European seedless types, which are mild in flavor, seedless, and have thin skins. The English cucumber is the most common variety and is readily available in retail markets. More recently, mini varieties have become popular and commercial production has increased due to consumer demand for healthy snacking alternatives. Cucumber plants are known to be highly sensitive to environmental changes, and sensitivity to spectrum is no exception. With the correct spectral balance, blue light can be used to increase the photosynthetic rate of cucumber plants. However, the ratio of red to blue light must be adequately maintained to ensure proper growth. Too much blue light and leaf area will decrease. Conversely, too much red light and photosynthetic rate decreases, leading to abnormal development. LumiGrow continues to research how light spectrum affects cucumber seedlings through transplant, to optimize production growth in greenhouse conditions LumiGrow Inc. LED Growers Guide - Vine Crops 15

16 LumiGrow LED Lighting Card Lighting Requirements for Cucumbers SEEDLING RECOMMENDATIONS PRODUCTION RECOMMENDATIONS Daily Light Integral (DLI) - sunlight + supplemental measured in mol m -2 d-1 Photoperiod based on 24-hour period Temperature (Day) Farenheit and Celsius C F C F Temperature (Night) Farenheit and Celsius C F C F Cucumber Crop Schedule Sow Stage days Transplant Stage 3-4 weeks Harvest Stage 2-3 months 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 16

17 Cucumber Lighting Recommendations Cucumbers are moderate to high-light plants. They grow best under a DLI of 20 to 35 mol m -2 d-1, but can withstand a higher DLI. In addition to high light conditions, cucumbers perform best at high temperatures, usually F (23-27 C) during the day and F (19-21 C) at night. While most benefits from supplemental lighting are seen during the winter months when sunlight is reduced, increased light on the plant canopy can still yield increases at high DLIs. The optimal photoperiod for cucumbers is 18 to 20 hours. Extending the photoperiod has been shown to increase the quantity CO 2 daily assimilated and reduce the respiration period, which results in higher growth rate and yield. The beneficial effects of extended day treatments is shown to increase as photoperiod increases, however as the plants get older a 4 hour dark period should be provided. Light Quality and Cucumber Growth Light quality has been proven to have significant effects on cucumber growth and morphology. LumiGrow s Smart Horticultural Lighting is designed to give growers a professional-grade tool for controlling these effects for plant development by finely-tuning light spectrum. By adjusting LEDs to emit specific wavelengths of light, growers can achieve desired plant responses at various phases of growth. When using light quality as a tool for controlling cucumber growth, it is important to establish production requirements, and use light accordingly to achieve specific growth goals. Much like any other production variable used for agriculture, light should be adjusted, measured, and maximized to achieve better growth. Through partnerships with major commercial cucumber growers in North America, LumiGrow has found that cucumber plants grown under LumiGrow LEDs targeted spectrum exhibit better resistance to certain plant diseases and pests. When developing a professional lighting strategy, it is beneficial to take into consideration the profound effects that red and blue light have on plant development. Unlike tomatoes, light quality requirements for optimal cucumber growth are still under debate. In supplemental lighting conditions, red light alone may be suitable for growth when ambient solar radiation meets blue light requirements. The addition of green light appears to neither increase nor decrease growth when added in sole-source environments. Research is currently underway to understand how light quality can further be used to direct cucumber growth LumiGrow Inc. LED Growers Guide - Vine Crops 17

18 LED Lighting By Growth Stage Currently, there are few production-specific experiments on greenhouse cucumbers. Through cooperation with research and commercial partners, LumiGrow has been working to better understand the best application of light for all stages of cucumber production, from seedling propagation through fruit production. Cucumber plants have traditionally been used as an experimental crop in a range of research studies focusing on light spectrum, which gives us a roadmap for how to apply light through the crop cycle. LED Lighting for Cucumber Seedlings Using the LumiGrow smartpar TM Wireless Control System, cucumber growers can adjust light spectrum to emit more red light for cucumbers being grown in the seedling stage. By defining light regiments by zone through the software platform, LumiGrow Smart LEDs can be easily managed to control multiple crops and stages simultaneously The seedling and transplant stage is critical to production, as greenhouse plants are normally established as transplants. Careful monitoring of plants and their environment is key during this stage to ensure good plant health and productivity. To better understand the effects of spectrum, researchers from the University of Arizona grew seedlings under ambient winter light conditions and three different ratios of supplemental red and blue light, to compare growth characteristics (see Research Study 2.1). Cucumber transplants had more commercially desirable characteristics and experienced increased growth under supplemental lighting in both high and low ambient DLI conditions (as seen in different locations during the winter). In this study, blue light did not show an increase in plant response and in many cases the all red treatment outperformed the others. For cucumber seedlings, it s best to supplement with higher ratios of red light to positively affect plant growth and morphology, as the sun provides enough blue light for proper cucumber growth in the greenhouse LumiGrow Inc. LED Growers Guide - Vine Crops 18

19 2.1 Research Study Using Light Quality to Control Cucumber Seedling Growth Researchers from the University of Arizona investigated the effects of red and blue spectral ratios on the growth of cucumber seedlings grown in a greenhouse. They looked at three supplemental light ratio treatments (0B:100R%, 4B:96R%, and 16B:84R%) providing 54 μmol m -2 s -1 compared to ambient light alone, in high DLI (16 mol m - 2 d -1 ) and low DLI (5 mol m -2 d -1 ) winter environments. In general, plants grown under supplemental LEDs out-performed those grown without supplemental lighting. Under high ambient light conditions, shoot mass increased by 20% and leaf number increased by 7.4% compared to the control. Under low ambient light conditions, the benefits of supplemental lighting were even greater, where cucumbers under each of the LED treatments showed at least 27% more biomass. Increased ratios of blue light resulted in decreased leaf area compared to other LED treatments, but still had 10% greater leaf area compared to no supplemental light. It s important to note that the reduction in leaf size in the higher blue light treatments did not negatively affect the photosynthetic rate. Results The benefits of supplemental lighting are evident from this study. The study shows that it is possible to grow cucumbers in the greenhouse under red light alone; however, increased ratios of blue did not negatively impact plant growth compared to the control. Overall supplemental light treatments resulted in a % increase in dry mass per 1% increase in DLI from supplemental lighting. Hernández, R., & Kubota, C. (2014). Growth and morphological response of cucmber seedlings to supplemental red and blue photon plux ratios under varied solar daily light integrals. Scientia Horticulturae, 173, LED Lighting for Cucumber Production Fewer studies have been done on fruiting cucumber plants than for cucumber seedlings, with most available yield studies focusing on the effects of blue light for cucumber production. Through these studies, we now understand that blue light can be used to increase chlorophyll content and increase net photosynthetic rate in cucumber production. Research done by the Agriculture and Agri-Food Canada Horticultural Research Centre found that supplemental lighting increased fruit growth rate, fruit biomass, and quantity of fruit harvested. For year-round cucumber production, there was a 70 to 80% increase in yield when lighting with 180 to 200 μmol m -2 s-1 compared to ambient light. Additionally, supplemental lighting has been shown to decrease the time to harvest by over 2 weeks LumiGrow Inc. LED Growers Guide - Vine Crops 19

20 Researchers from the Lithuanian Institute of Horticulture studied the effects of LED lighting on cucumber transplants and the after-effect on yield. They found that transplants that were grown under LED treatments began flowering sooner than HPS and were harvestable 5 to 8 days before HPS plants. They found that plants grown under LED treatments outperformed plants grown under HPS in terms of overall crop quality and desirable crop characteristics. This study is useful for cucumber growers because it stresses the importance of meeting lighting requirements for seedlings, as these effects carry over to production, and ultimately affect time to flower and harvest after seedlings have been transplanted into the production system. Additional research conducted by the LumiGrow Plant Research Group done in collaboration with commercial partners has shown benefits of growing plants under LEDs, resulting in increased growth and yield compared to HPS. The Future of Cucumber Spectral Science Cucumbers are proving to be at least as sensitive to changes in light quality as tomatoes, especially in response to blue light. We predict it will be increasingly useful to change supplemental lighting ratios throughout the growth cycle. For example, blue light may be important during seedling production to control plant height or increase photosynthesis, but after transplant an increase in red light could be used to stimulate increased leaf expansion and vegetative growth. Current research with cucumbers still shows that regardless of spectrum, added light can increase production even in high-light conditions. The use of light to fight disease is also emerging as a viable option for cucumber production. Preliminary work has shown that LEDs and specific spectral ratios may be able to prevent the spread powdery mildew and repel white flies. LumiGrow is further pursuing research to instruct growers on ways to use light for fighting plant diseases. WHAT CUCUMBER GROWERS ARE ACHIEVING W/ LEDS Inrease yield, fruit quality, and longer-producing plants due to spectral quality and control strategies Cucumber producers focused on higher yields are seeing 1.5% increase in dry mass per 1% increase in DLI Blue light is being used by innovative growers to increase the photosynthetic rate of their cucumber plants Dramatic energy-savings, boosting the overall ROI of professional cucumber facilities 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 20

21 LumiGrow In-House Research Glenwood Farms - Cucumbers About Glenwood Results Glenwood Valley Farms is a large producer of greenhouse vegetables located in Langley, British Columbia. The company prides itself for its hand-picked, locally grown vegetables. Glenwood was interested in LEDs for their energy saving abilities, as well as for achieving differences in plant growth associated with lighting type. The LumiGrow Plant Research Group worked in partnership with Glenwood Valley Farms to trial winter Long English and mini-cucumber production in HPS-lit and LED-lit bays. Overall, the LED-lit plants out performed HPS-lit plants. Both the mini-cucumbers as well as the Long English cucumbers produced significantly more yield than the HPS-lit plants in the same time. Moreover, LED-lit plants were left in production longer allowing for additional production. Compared to the HPS-lit plants, the LED-lit plants were superior in overall growth and production. Lighting was installed after cucumbers were already in their production bays. Key Findings LED-lit plants had greater yield compared to HPS-lit plants Disease pressure was reduced for LED-lit plants. LED-lit plants had increased longevity, with improved yield and plant health over time compared to HPS-lit plants LumiGrow Inc. LED Growers Guide - Vine Crops 21

22 WHAT YOU WILL LEARN IN THIS SECTION: Lighting requirements for peppers How light intensity, quality, and photoperiod affect pepper crops across growth stages What leading researchers are learning about light s interaction with peppers Lighting Sweet Peppers Sweet peepers are a popular greenhouse crop due to increased yield and quality when compared to field-grown crops. Production of red, yellow, and orange sweet peppers has been increasing since the early 2000s. As of 2009, global pepper production has exceeded 14 million metric tons. High market prices and increased consumer demand has encouraged growers to consider the economic viability of this crop. Traditionally, greenhouse pepper crops do not carry a fruit load through December or January because of low light levels, but supplemental lighting has presented an opportunity to take advantage of high commercial prices outside of field production seasons. LED lighting has been of particular advantage for growers using light quality to direct plant growth, as well as mitigate high electrical prices in many northern regions. Peppers are not traditionally lit, meaning that there has been little research conducted on the effects of light intensity and quality on pepper production. They are slow growing in comparison to tomatoes and cucumbers, requiring around 75 days from transplant to first harvest. Therefore running comprehensive yield trials is a massive undertaking. Academic research on peppers has nonetheless been instrumental to understanding light quality s effects on plant growth and development. The LumiGrow Plant Research Group is currently exploring light s effects on pepper production with some of North America s leading commercial growers LumiGrow Inc. LED Growers Guide - Vine Crops 22

23 LumiGrow LED Lighting Card Lighting Requirements for Peppers SEEDLING RECOMMENDATIONS GRAFTING RECOMMENDATIONS PRODUCTION RECOMMENDATIONS Daily Light Integral (DLI) measured in mol m -2 d-1 Photoperiod based on 24-hour period Temperature (Day) Farenheit and Celsius C F Variable C F Temperature (Night) Farenheit and Celsius C F Variable C F Sweet Pepper Crop Schedule Sow Stage 6-8 weeks Transplant Stage 2-3 weeks Harvest Stage 7-8 months 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 23

24 Pepper Lighting Recommendations During production, a heavy fruit load is desirable; however, there is a risk of fruit abortion if light demands cannot be met Originating in South and Central America, peppers are adapted to high light conditions and produce best under high DLI ranging from 25 to 50 mol m -2 d-1. A DLI of at least 12 mol m -2 d-1 is recommended for seedling production, but as this normally occurs during the winter months, supplemental light is needed to reach the target DLI. During production, a heavy fruit load is desirable; however, there is a risk of fruit abortion if light demands cannot be met. Supplemental lighting can also reduce the uncertainty and fluctuations of spring DLI. A photoperiod of 18 to 20 hours is recommended for pepper production. Pepper plants can be lit continuously, however significant benefits to growth and yield are not seen past 20 hours. Light Quality and Pepper Growth Light quality has been proven to have significant effects on pepper plant growth and morphology. LumiGrow s Smart Horticultural Lighting is designed to give growers a professional-grade tool for controlling these effects to finely tune plant development. By adjusting LEDs to emit specific wavelengths of light, growers can achieve desired plant responses at various phases of growth. When using light quality as a tool for controlling pepper growth, it is important to establish production requirements, and use light accordingly to achieve specific growth goals. Much like any other production variable used for agriculture, light should be adjusted, measured, and maximized to achieve better growth. When developing a professional lighting strategy, it is beneficial to take into consideration the profound effects that red and blue light have on plant development. Peppers are sensitive to changes in light quality, but take longer to show changes because of their slow growing nature. In growth chambers, peppers have been successfully grown under blue and red light alone, in some cases needing as little as 1% blue light for growth and development, similar to plants grown under more broad-spectrum sources. LumiGrow is currently undergoing comprehensive research to understand the effect of supplemental light quality on pepper growth and production LumiGrow Inc. LED Growers Guide - Vine Crops 24

25 LED Lighting By Growth Stage Most of our understanding of how light affects the growth of peppers is from sole-source studies. The few supplemental lighting studies available show that background solar radiation changes light quality needs, however the following information provides a good basis for using light quality to influence pepper growth at specific crop stages. LED Lighting for Pepper Seedlings LumiGrow currently recommends lighting pepper seedlings with a mix a red and blue light for robust growth, as blue light exhibits benefits for pepper plant morphology The slow growth cycle of peppers makes the seedling stage vital. It is important to ensure that transplants are of the highest quality before beginning transplanted into a full production system. Relatively early experiments using LEDs looked at the practicality of growing peppers under LEDs alone. At the time, only red and far-red LEDs had appreciable output, so blue light was added from fluorescent lamps. Researchers found that peppers grown under red alone had lower dry mass compared to those under 100:1 red to blue light. The addition of far-red to red light resulted in taller plants. Looking at increasing blue light ratios, leaf thickness and chlorophyll count increased along with blue light percentage The LumiGrow Plant Research Group is developing trials to further understand pepper growth under supplemental lighting. LED Lighting for Pepper Grafting Preliminary research shows that LEDs can be used to further increase resistance of plants against specific plant diseases and pests Much like how grafting has proven especially important for tomatoes, grafting is important to pepper production to ensure disease resistance. The healing stage is the most critical stage for plant grafting. Of high importance to those looking at the use of LEDs for grafting is the use of light quality or spectrum to promote plant healing and acclimation during the grafting stage. For pepper grafting, it is best to light with intensities up to 180 μmol m - 2 s LumiGrow Inc. LED Growers Guide - Vine Crops 25

26 3.1 Research Study Effects of Light Quality on Pepper Grafting Researchers from Seoul National University studied the effect of light quality on pepper graft healing and acclimation. Four-week-old pepper scions and rootstocks were grafted and then grown under fluorescent lamps (control), red, blue, and red + blue LEDs at PPFs of 50, 100, or 180 μmol m -2 s-1. They found that higher light intensities increased growth regardless of light quality. Peppers grown under blue LEDs alone had 20% higher CO 2 exchange and greater shoot mass compared to those grown under fluorescent lamps. Grafting success was not affected by light quality. Growing grafted peppers under red light alone resulted in lower relative chlorophyll readings, decreased dry weight, and abnormal development (leaf epinasty). Fig. 2, from Jang et al. (2013). The effects of light quality and intensity on the morphology of grafted pepper transplants during the six day healing and acclimatization period. Jang, Y., Mun, B., Seo, T., Lee, J., Oh, S., & Chun, C. (2013). Effects of light quality and intensity on the carbon dioxide exchange rate, growth, and morphogenesis of grafted pepper transplants during healing and acclimation. Kor. J. Hort. Sci. Technol., 31(1), LED Lighting for Pepper Production As any pepper grower knows, production is slow and can be finicky. Research trials with peppers take time and considerable effort. Peppers have not traditionally been managed with supplemental light, meaning there are few full-production lighting trials. As interest in yearround greenhouse pepper production increases, so too will pepper research. Research done by the Agriculture and Agri-Food Canada Horticultural Research Centre has still found some useful evidence for supplemental light for peppers, finding that supplementing peppers with 120 μmol m -2 s-1 of light increased total fruit weight harvested by 18% to 33%. Agri-Food Canada found that supplemental light of 120 mol m -2 d -1 increased total fruit weight harvested by 18% to 33%. It has also been proven that in some cases, peppers grown under HPS lamps can exhibit leaf curling, where blue light is often preventative to such curling. Researchers from the University of Arizona observed 57% less leaf curl on peppers grown under blue supplemental lighting from LEDs compared to plants grown under red LEDs or HPS lamps. Although this response can be variety specific, adding blue to supplemental lighting ratio may be likely to reduce leaf curl, which optimizes photosynthesis by 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 26

27 providing a more flat surface much like that of a solar panel. The LumiGrow Plant Research Group has partnered with outside research institutions to further explore the effects of LED light for pepper growth and morphology in the greenhouse. The Future of Pepper Spectral Science Research has shown that there is enormous potential for spectral science applications for sweet pepper production. Research has mainly focused on increasing photosynthesis in seedlings, but additional research on pepper production is being developed. Like tomatoes and cucumbers, sweet peppers show signs of sensitivity to changes in light quality and it currently appears possible to control photosynthesis and morphology with added amounts of blue light. Based on previous research, we believe it s likely possible to further control sweet pepper flowering and fruiting using light as a growth variable. WHAT PEPPER GROWERS ARE ACHIEVING W/ LEDS Reduced leaf curling and flower abortion due to LEDs potential for targeted spectrum and lower ambient temperatures Boost fruit quality by delivering more red and blue light to your crops, while using adjustable lighting to manipulate crop growth Reduce operational costs with dramatic energy-savings and monitor electricity usage using LumiGrow smartpartm software Increase production efficiency by decreasing time-to-flower, and managing growth stages effectively with light 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 27

28 LumiGrow In-House Research Harrow Research Centre - Peppers Harrow Research and Development Centre is part of Agriculture and Agri-Food Canada s national network of research centers. Their mission is to develop and transfer new technologies for the production and protection of greenhouse and field crops. The Centre s research prioritizes growers problems and needs. To better achieve this mission, Harrow began investigating the use of LED supplemental lighting for vine crops. Due to the profound effects that light intensity and quality can have on vegetable growth and productivity, the research center aimed to determine the best practice for growing vine crops using LED lighting. The Research Centre is currently conducting a study on greenhouse sweet peppers in collaboration with LumiGrow. Harrow is seeking to develop lighting strategies tailored to individual crops needs, with special interest in improving fruit yield, quality, and nutritional value. To test the effects of LED lighting on sweet peppers, a variety of lighting techniques are being utilized. Harrow selected LumiGrow as their toplighting fixture due to the system s ability to adjust spectrum, and have begun to taken advantage of spectral controllability in previous lighting trials by changing the lighting environment to promote desired growth. Find Results of the Trial at Harrow Research Centre By Signing Up for LumiNews at: 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 28

29 Pro Series E Smart Horticultural Lighting Each LumiGrow Pro Series E fixture comes enabled with full-power functionality for maximum light intensity and robust plant growth. For automated control over light intensity, spectrum, and photoperiod, upgrade by syncing your fixtures to the LumiGrow smartpar TM Wireless Control System. Get More Light With Less Energy Features and Benefits Achieve up to 70% in energy savings versus HID Targeted Output Drives Healthy Plant Response Adjustable-spectrum (w/ smartpar) Runs cooler than HID lighting Small hardware footprint minimizes plant canopy shadowing RoHS Compliant (mercury and leadfree) light energy output cul / UL and CE certified 5 Year Warranty White Light View Mode Maintains light output longer than HID Stay Rooted To Your Grow w/ smartpar When you order smartpar, LumiGrow ships you smartpar wi-fi modules for all of your LumiGrow fixtures Our smartpar Implementation Specialist visits you on-site to provision the smartpar network Begin controlling your lights from any phone, tablet, or computer! LumiGrow Spectrum Double-Ended HPS Spectrum Pro Series E Spectral Output Blue Light 20% ( nm) Green Light 5% ( nm) Red Light 75% ( nm) wavelength (nm) 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 29

30 smartpar Wireless Control System Control Your LumiGrow LED System from Anywhere, at Anytime! LumiGrow smartpar is a wireless control platform that enables you to automate lighting zones and adjust LumiGrow LEDs from your phone, tablet or computer. The SMARTEST Horticultural Lighting System in the World! Adjustable Spectrum Enable adjustable spectrum for your LumiGrow LEDs, to elicit healthy plant response and maximize production Automated Zones Control your lighting with precision by setting up automated lighting zones, no wiring needed Notifications Monitor your power usage to stay on top of your lighting costs and optimize operational efficiency Unrivaled Security All data & communications are kept secure using the leading bank-level security encryption Smart Lighting Schedules Easily toggle between lighting programs to manage multiple zones easily without moving your lights White-Light Mode Quickly toggle between grow-mode and view-mode to easily inspect plants 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 30

31 Ready to Discuss Your Own Vine Crop Lighting Strategy? LumiGrow Lighting Specialists and Plant Scientists will assist you in developing your own smart horticultural lighting strategy based on your crop, location, and growth objectives. LumiGrow provides the industry s most knowledgeable support and will generate a detailed light plan based on leading research, using precise lighting and plant growth metrics Contact a LumiGrow Lighting Specialist at (800) ; lighting@lumigrow.com; or visit our website for additional information at 2017 LumiGrow Inc. LED Growers Guide - Vine Crops PAGE LumiGrow Inc. LED Growers Guide - Vine Crops 31

32 References Brazaityté, A., Duchovskis, P., Urvonaviciuté, A., Samuoliené, G., Jankauskiené, J., Kasiuleviciuté-Bonakéré, A.,... Žukauskas, A. (2009). The effect of light-emitting diodes lighting on cucumber transplants. Zemdirbyste-Agriculture, 96, Dorais, M. (2003). The use of supplemental lighting for vegetable crop production: light intensity, crop response, nutrition, crop management, cultural practises. Canadian Greenhouse Conference. Dzakovich, M., Gomez, C., & Mitchell, C. (2015). Tomatoes grown with light-emitting diodes or high-pressure sodium supplemental lights have similar fruit-quality attributes. HortScience, 50(10), Folta, K., & Carvalho, S. (2015). Photoreceptors and control of horticultural plant traits. HortScience, 50(9), Hernández, R., & Kubota, C. (2014). Growth and morphological response of cucumber seedlings to supplemental red and blue photon flux ratios under varied solar daily light integrals. Scientia Horticulturae, 173, Hernández, R., & Kubota, C. (2014). Growth and morphology of greenhouse bell pepper transplants grown under supplemental LEDs and HPS lighting ASHS Annual Conference. Hochmuth, G. (2012, January). Production of Greenhouse Tomatoes Florida Greenhouse Vegetable Production Handbook, Vol 3. Retrieved from University of Florida IFAS Extension: Hogewoning, S., Trouwborst, G., Maljaars, H., Poorter, H., W., v. I., & Harbinson, J. (2010). Blue light dose-responses of leaf photosynthesis morphology, and chemical composition of Cucumis sativus grown under different combinations of red and blue light. J. Exp. Bot., 61, Jang, Y., Mun, B., Seo, T., Lee, J., Oh, S., & Chun, C. (2013). Effects of Light Quality and Intensity on the Carbon Dioxide Exchange Rate, Growth, and Morphogenesis of Grafted Pepper Transplants during Healing and Accliation. Kor. J. Hort. Sci. Technol., 31(1), LumiGrow Inc. LED Growers Guide - Vine Crops 32

33 Jovicich, E., Cantliffe, D., Sargent, S., & Osborne, L. (2004, July). Production of Greenhouse- Grown Peppers in Florida. Retrieved from University of Florida IFAS Extension: Massa, G., Kim, H.-H., Wheeler, R., & Mitchell, C. (2008). Plant Productivity in Response to LED Lighting. HortScience, 43(7), Menard, C., Dorais, M., Hovi, T., & Gosselin, A. (2006). Developmental and physiological responses of tomato and cucumber to additional blue light. Acta Hortic, 711, doi:doi: /ActaHortic Ministry of Agriculture Food and Rural Affairs. (2010). Growing Greenhouse Vegetables in Ontario Toronto: Queen's Printer for Ontario. Pocock, T. (2015). Light-emitting diodes and the modulation of specialty crops: Lighting sensing and signaling networks in plants. HortScience, 50(9), Taiz, B., & Zeiger, E. (2010). Plant Physiology (5th ed.). Sunderland, MA: Sinauer Academic Press. Thomas, B., & Vince-Prue, D. (1997). Photoperiodism in plants. San Diego, CA: Academic Press. Tomatoes. (2017, March). Retrieved from AgMRC: vegetables/tomatoes/ Trouwborst, G., Oosterkamp, J., Hogewoning, S. W., Harbinson, J., & Van Ieperen, W. (2010). The responses of light interception, photosynthesis and fruit yield of cucumber to LEDlighting within the canopy. Physiologia Plantarum, 138, LumiGrow Inc. LED Growers Guide - Vine Crops 33

34 Contact a LumiGrow Lighting Specialist at (800) lighting@lumigrow.com or visit our website for additional information at LED Growers Guide for VINE CROPS 2017 LumiGrow Inc. LED Growers Guide - Vine Crops 34