Hort Americas and VegBed Team Up to Offer New Microgreen Medium for Farms

Hort Americas partnering with VegBed to offer their sustainable bamboo fiber microgreen mats

Press Release – NEW YORK, NY [February 12, 2019] – Hort Americas, North America’s top commercial horticultural supplier, and VegBed, the leader of innovative hydroponic growing mediums have announced today an exciting new partnership to offer microgreen farms a sustainable medium to grow with.

Continue reading Hort Americas and VegBed Team Up to Offer New Microgreen Medium for Farms

NASA developing LED light recipes that astronauts and growers can use

The LED light recipes that NASA scientists are developing on Earth could eventually be used by astronauts in space and growers on the ground to optimize the production of food crops.

National Aeronautics and Space Administration (NASA) has been growing plants in space for research since the early 1980s. Within the last five years, NASA has been focusing on growing plants in space primarily for food production and as an astronaut life support system.

Continue reading NASA developing LED light recipes that astronauts and growers can use

Growing microgreens with LED grow lights in Sonora, Mexico

(Español abajo.)

Urban grower Karla Garcia is proud to announce the creation of her new company, Microgreens FLN based in Sonora, Mexico. Karla is a recent graduate with honors and a master’s degree in plant science from the University of Arizona. She is proud of her company’s commitment specializing in microgreens production using an indoor vertical farming strategy. Microgreens are an emerging class of specialty leafy greens and herbs. The crops are harvested when the cotyledons are fully developed and in some cases when the young plants have one true leaf.

Continue reading Growing microgreens with LED grow lights in Sonora, Mexico

Local by Atta rebuilds vertical farm with GE LEDs after devastating fire


Case File Facts

COMPANY: Local by Atta

LOCATION: Moncton, New Brunswick, Canada

CROPS: Local by Atta produces a variety of lettuces, basil, kale, Swiss chard, bok choy, cilantro and microgreens. Products are sold at farmers markets, health food stores, grocery stores, restaurants and through a weekly basket  program. The basket program is expected to increase sales as the company looks to expand with pick up at local businesses, municipal buildings and its new production facility.

TECHNOLOGY: GE Arize Lynk LED Growing System

Continue reading Local by Atta rebuilds vertical farm with GE LEDs after devastating fire

P.L. Light Systems’ HortiLED series of grow lights meets the requirements of controlled environment agriculture

Whether greenhouse, vertical farm or warehouse growers are propagating or producing ornamental, vegetable or cannabis crops, P.L. Light Systems offers the LED fixtures to meet their lighting needs.

P.L. Light Systems develops and manufactures supplemental lighting systems for the horticultural industry. The nearly 40-year-old company manufactures traditional light sources, including high pressure sodium (HPS) and metal halide, as well as its own light emitting diode (LED) fixtures.

“There are a lot of lighting products hitting the market right now, especially when it comes to LEDs,” said Eric Moody, P.L. Light Systems western USA Lighting Solutions Specialist. “The future of the horticultural lighting market is moving toward LEDs as the technology continues to advance. Every week it seems like there is another company entering the horticultural lighting market. Growers need to carefully look at the lighting companies they are considering working with. How long has a company been around and is it focused on horticulture or is it just buying circuit boards and selling them as LED horticulture lights?”

Even though P.L. Light Systems has been marketing horticulture grow lights for nearly 40 years, it was not one of the first companies to offer LED lights. “One of the reasons that we weren’t one of the first companies is because of the intensities and efficiencies of LEDs,” Moody said. “In 2014-2015 the market started to see LED diodes that could deliver 2.1 micromoles per joule (μmol∙J–1). When this occurred everyone that was selling LEDs to the horticulture industry got excited.

“Double-ended HPS lamps that are used in horticulture put out 2,100 micromoles per 1,000 watts, which is 2.1 μmol∙J–1. So what happened is LEDs finally equaled HPS. LEDs didn’t surpass HPS. When this happened P.L. started looking into the LED market and to surpass what was available.”

P.L. Light Systems’ HortiLED TOP and HortiLED INTER fixtures are finalists in the Horticultural Lighting Category for LEDs Magazine’s 2017 Sapphire Awards. The awards will be presented March 1, 2017, in Anaheim, Calif.


P.L. Light Systems HortiLED TOP

P.L. Light Systems HortiLED TOP light is a fully enclosed fixture with an integrated driver that delivers 2.7 μmol∙J–1. The TOP fixture measures 38 inches long by 4.7 inches wide by 3.7 inches tall and weighs 18 pounds. The fixture is available in two distribution angles, 80º and 150º, and light spectrum of red/blue, red/white, full spectrum and customized.

“P.L. started in the greenhouse market so we are catering to that segment of the market even though there are a lot of indoor growers using our fixtures,” Moody said. “We want to be sure everything we manufacture is able to be used in a greenhouse.

PL Light Systems HortiLED toplighting

“The TOP fixture drivers are driving the diodes to 2.7 μmol∙J–1. But the diodes we are using are capable of going above 3 μmol∙J–1. We are driving our diodes to a lower percentage because we don’t want to overheat them and we want them to last for 28,000 hours. We are better able to control the heat by not overdriving the diodes. Our goal is to have totally passive cooling so the fixture can be hung right up under a truss and it is fully enclosed.” Moody said having a totally enclosed fixture offers an advantage over other toplight LEDs on the market.

“Other manufacturers are either installing fans in their fixtures or they are mounting the drivers separately,” he said. “The LEDs with fans built into the fixtures can suck in dust and insects. These fixtures can short out because they get a build-up of debris inside the fixture. The fans push air across an electrical circuit board. There are also water-cooled fixtures. There is a water line running from one fixture to the next.

“Other manufacturers’ fixtures are large units in order to get the light output. These fixtures might work for some indoor growers, but they’re not going to work in a greenhouse. These larger fixtures reduce the amount of sunlight reaching the plants by casting shadows over them.”

Moody said with LEDs the light is very directional so it doesn’t cover as big of a footprint as HPS.

“We offer two TOP light LEDs that have different distribution patterns,” he said. “It’s not a reflector, it’s the diode itself. We have an 80º diode which is very common. This fixture puts out an 80º wide distribution pattern. We also have a 150º diode that puts out a much wider distribution pattern. This enables us to cater light plans to the growers’ crops. It offers a lot of room to move up and down depending on how far the fixtures need to be from a crop.”


P.L. Light Systems HortiLED INTER

The HortiLED INTER fixture is made for tall vine vegetables, ornamentals and some cannabis production. “The fixtures are mounted down the center of the crop,” Moody said. “It is supplementing the light that is being received from above the crop. For a 14-foot tall greenhouse tomato crop a grower may have HPS or LED toplights above and then the interlights below. Sometimes growers will use two rows of interlight fixtures in order to get more light deeper into their crops.

“The INTER fixture has the same high output diode as our TOP fixture, but because of the cover on the INTER fixture, the output reaches 2.5-2.6 micromoles per joule depending on the light spectrum.”

The INTER LED is a fully enclosed fixture equipped with a polycarbonate cover that keeps it totally waterproof. Moody said this ensures that the fixtures are not affected by high humidity environments, mist systems and spray applications.

The INTER fixture measures 48 inches long by 2.2 inches wide by 4.8 inches tall and weighs about 4 pounds. The fixture operates with an external driver and is available with a red/blue spectrum.

“With an interlighting fixture hanging in the crop, the light distribution pattern should go out to the sides hitting all of the leaves that are around the fixture,” Moody said. “Our INTER fixtures put out what looks like a butterfly wing pattern. The light pattern goes out sideways, but at the same time it also goes down. We use reflector technology to direct the light.

“The INTER fixture has one bank of LEDs. Some other interlight fixtures are larger and heavier units because they have two LED circuit boards back-to-back putting light out on each side of the fixtures.”

Eight of the 4-foot INTER fixtures can be run together using one driver. Moody stated interlight fixtures need to be lightweight because growers hang them on crop wire or whatever is being used inside the crop.

The INTER fixture is not yet available for the U.S. market. “We are still finalizing our UL listing in the U.S. for the INTER fixture,” Moody said. “This fixture is available in the red/medium blue spectrum. The INTER fixture is expected to be available for the U.S. market by the end of the first quarter.”


P.L. Light Systems HortiLED MULTI

The P.L. Systems HortiLED MULTI fixtures are being used primarily for propagation, young plant production and vertical farming.

“Just like with the TOP fixtures, our MULTIs are available in 80º and 150º distribution outputs,” Moody said. “We also have two different lengths, basically a 4-foot (122 cm) and 5-foot (152 cm) fixture. These fixtures have an integrated driver and are available in low and high output versions. There are some applications where a low output is needed, better uniformity, closer to the crop like with tissue culture and early plant propagation applications. The high output fixture is for later in propagation or for propagation of bigger plants. For the MULTIs we can do numerous light spectrum combinations.”

Moody said the MULTI fixtures are ideal for vertical farming applications. “We can do vertical growing with lettuces, mixed greens, microgreens, all of those under these lights as well. Our MULTI lights have a higher output than most other LEDs used for this application.


“For propagation most growers use multiple layers. Typically they are built with two to four layers on racks. The MULTIs were designed to be installed on the underside of a rack pointing down toward the crop below it, from 9 inches to as far away as 2 feet from the crop.”

Grodan rockwool substrates offer growers more control

Grodan stone wool products offer the benefits of high irrigation efficiency, plant steerability and uniform crop development.

Grodan stone wool substrates are made from basalt rock that is processed at a very high temperature (over 2,900ºF). This hygienic, inert substrate offers vegetable and ornamental plant growers the opportunity to control growth from propagation to harvest.

“Grodan stone wool products are inert,” said Rens Muusers, Grodan Technical Sales Manager for the USA. “This means the grower has full control over what is happening in the substrate. Being inert, Grodan stone wool doesn’t bind nutrients and chemicals like other substrate types may do. Any fertilizers, pesticides or other chemicals, including growth regulators, that are applied to the stone wool are available to plants.

Linked to stone wool’s inert nature, Muusers stated growers have more opportunities to steer their crops.

“Other substrates that aren’t inert may bind elements, pesticides or other chemicals that are applied to enhance plant growth or health,” he said. “This may result in having to apply more of a chemical in order to have the same efficacy. The amount of chemical that will need to be applied to stone wool will be lower and it will be more effective than in non-inert substrates. This also helps growers to minimize their input costs.

“Using methods to control water content and EC (electrical conductivity) levels within the substrate allows growers to influence plant growth.”

Muusers stated by controlling the water content and EC in the stone wool, growers can influence the plant balance between vegetative and generative development.

“The steerability offered by Grodan products can result in earlier production, improved plant, fruit and flower quality and improved plant health,” he said. “All of these benefits result in better resilience to insect pests and disease pathogens.

“Also, stone wool can have a buffering impact on the pH in the nutrient solution, slightly increasing pH in the substrate. This increase is minimal compared to the impact of plant and microbial activity in the root zone on pH.”

Muusers indicated another benefit of using stone wool is crop uniformity.

“Because Grodan stone wool products are manufactured in state-of-the-art facilities with strict standards and quality controls, it is a very uniform substrate,” he said. “Depending on the Grodan product being used, this allows growers to produce very uniform crops. The uniformity of seedlings produced in stone wool plugs results in faster germination and quick crop establishment.


Grodan AO plugs and Grodan AX plugs

Grodan AO and AX stone wool plugs are ideal for starting many crops. The plugs are available in sheets that fit into 1020 trays. AO plugs are connected to each other at the top of the plugs. AX plugs are attached to each other at the bottom of the plugs. Muusers said there are also some options in regards to the seeding hole size as well as with the dimensions of the plugs.

“The properties of the AO plugs are exactly the same as the properties of the AX,” he said. “The only difference is where the plugs are attached to each other.

Grodan AX 25/40 cube with lettuce roots and stem post-harvest.

“AO plugs are ideal for NFT systems with smooth gutter surfaces and also for deep flow systems. Some NFT systems use gutters with grooves on the surface for which growers may prefer the wider base and greater bottom surface area of the AX plugs which may be more stable in these systems.”

Muusers said both plugs are used mainly for leafy greens and culinary herb production. There are also growers who are using them for aquatic plants.

Grodan Cress Plate

The Cress Plate is a fairly new product used primarily for the production of microgreens. It is the thinnest product of Grodan. It is only 1 cm thick, less than ½ inch.

Cress Plates come in two sizes. One size fits into 1020 trays. A larger size is used by some growers who need customized sizes. Growers are able to cut the Cress Plate sheet to the exact size they need.

“The Cress Plate has the same beneficial characteristics as other Grodan products,” Muusers said. “It’s inert, clean and hygienic. It’s a uniform product. It holds water evenly. The Cress Plate also provides quick, easy germination and even development of a microgreen crop.”

Muusers indicated growers use Cress Plates in a couple of ways.

“Some growers sell the microgreens with the Cress Plate, essentially selling a living product,” he said. “This allows the end consumer to use the freshest product longer, something that is valued by customers like restaurants. “Growers who produce baby greens and baby lettuce tend to harvest off of the Cress Plates. By harvesting higher up the plants, the plants continue to grow and produce for several harvests. This multiple harvest method is preferred to the uncommon practice of reusing substrates.”

Muusers stated reusing the Cress Plates is risky, just like reusing any substrate.

“There is the possibility of sterilizing the used substrate with steam or some other technique,” he said. “When a sterilizing technique like steam is used, it can have a negative impact on the properties of the substrate. I wouldn’t recommend harvesting and then resowing on top of a previously used Cress Plate because of the risk with potential disease issues and the potential negative impact on germination and growth.”

Grodan Delta Blocks

Grodan blocks come in different sizes and are ideal for both ornamental and vegetable crops.

“Depending on the crop, once a seedling is germinated in a plug it can be transferred into a block and then transplanted into a finish substrate to be grown on,” Muusers said. “Tomatoes and peppers are usually propagated in plugs and then transplanted into blocks. The final grower purchases the young plants in blocks and transplants them into the final substrate such as Grodan slabs. For cucumbers, which are a relatively quick crop, those are sometimes sown directly into blocks, instead of plugs.”

There are different size blocks for different size crops. A standard block size is 10 cm-by-10 cm-by-6.5 cm, which is referred to as a 4-inch block.

Muusers indicated that some growers put multiple plants into one block depending on the crop.

“For tomatoes, growers are looking for a certain head density per square meter,” he said. “The head density per square meter is sometimes achieved by growing multiple plants or by pinching the plants. Tomatoes are the primary crop that growers plant more than one seedling in a block.”

Muusers stated this method of planting multiple plants is also done with cucumbers and peppers. Another reason a grower sows multiple plants into blocks is to try to save on the cost of the blocks.“Some growers use 6-inch blocks instead of 4-inch blocks and put two plants in them,” he said. “In my opinion, it is always better to put one plant in one block. There is less competition resulting in better seedling uniformity as well as a more uniform crop.”

The blocks, like the plugs, are inert and are steerable. Muusers stated the blocks are also important in regards to irrigation efficiency—how the water content and more particularly, the EC, are refreshed within the substrate.

“Grodan focuses on good root growth and uniform root growth throughout the blocks,” he said. “Also, the blocks need to be able to withstand the rigors of handling during propagation. Their structure must remain stable throughout the growing process to be able to support the plants especially when the blocks are moved around. The blocks won’t break or fall apart.”


Grodan Gro-Slabs

Muusers indicated that Grodan slabs come in different product types developed to meet the challenges and needs of different crops.

“We have different slab types for different applications,” he said. “The slabs differ in fiber orientation and fiber thickness to deliver the kind of functionality a grower is looking for. The Grodan plugs and blocks have the same fiber orientation. They are designed for quick root establishment.”

There are Grodan slabs designed for vegetable crops. These crops are usually short term, less than one year. There are slabs designed for longer horticultural ornamental crops that are grown for longer than a year. The slabs for long term crops, including cut roses and gerbera, have a stronger fiber structure to withstand the longer production period.

“Grodan slabs are very uniform,” Muusers said. “Since the substrate is inert, they offer a high degree of crop steerability. This offers a lot of options for irrigation strategies combined with the substrate to influence plant development in a vegetative or generative way.”


David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com.


Voices of Horticulture: Dean Kopsell, University of Tennessee

Dean Kopsell greenhouse University Tennessee



Dean Kopsell greenhouse University TennesseeDean Kopsell, University of Tennessee
Eating marigold petals

Dr. Dean Kopsell talks about why we should eat marigold petals and what his students found to be the best red to blue ratio for peak carotenoid concentrations.
Dean is a professor at the University of Tennessee and has studied an eclectic range of crops including Arabidopsis, basil, broccoli, cilantro, kale, lettuce, microgreens, onions, purslane, spinach, squash, turfgrass, and tomatoes.

1. Dean’s UT url:

2. Selected work of Dean Kopsell:

3. Dean’s Social Media:
Dean on Twitter: @UTPhytonut

Dean on LinkedIn: https://www.linkedin.com/in/dean-kopsell-5b707a45

LEDs have the potential to change how crops are grown

The use of LED grow lights to provide specific light wavelengths could allow growers to increase nutritional values of edible crops, enhance the intensity of foliage and flower color and improve the postharvest longevity of ornamental and edible crops.

Improvement in the light intensity delivered by light emitting diodes (LEDs) is helping to expand their use for the production of both edible and ornamental crops. Research with LEDs has been going on for about 30 years. Only within the last 10 years have increases in the light
intensities of LEDs allowed researchers to study the direct effects of narrow wave bands of light on plant physiology.


“LEDs are now available to deliver all blue, all red, all green, all yellow light or mixtures,” said University of Tennessee plant sciences professor Dean Kopsell. “White LEDs are almost a broad spectrum light source. White LEDs are actually mostly blue light with a little bit of red, yellow and green light with a white phosphor over them.”

Kopsell and his colleagues at the University of Tennessee are studying the impact individual types of light can have on the nutritional qualities of edible crops. Their work is focusing on crops that can be produced relatively quickly in 25-35 days, including microgreens and baby greens. They have also begun looking at some herbal crops including basil, tarragon and chives.

Researchers at the University of Tennessee are finding that exposing plants like brassicas to blue light is having a significant effect on their nutritional values. Photos courtesy of Dean Kopsell, Univ. of Tenn.


“Some of the unique things we are finding are when we change the light quality environment, going away from broad band light sources like fluorescent, incandescent and HIDs, and exposing plants to narrow band wavelengths of red and blue light, many things are changing in the plants. These narrow bands of light are having an effect on several plant quality parameters from a metabolic standpoint.”


Potential of specific light wavelengths


University of Tennessee researchers have found that exposing plants to narrow wavelengths of the light spectrum has resulted in the increased production of antioxidants and anti-carcinogenic compounds within the plants.

“What is even more interesting is some of the primary metabolites like the mineral nutrients are also increasing,” Kopsell said. “We are shifting the light ratios and putting more blue light into the mix. Blue light is close to the ultraviolet (UV) range and has higher energy values than red light. Because of the higher energy level associated with blue light, the more blue light we are exposing the plants to, it seems the more significant the results are on nutritional values.

“We haven’t got hard data yet, but everything that we can see, smell and taste, these blue lights not only affect nutrient uptake, and anti-oxidant metabolism, but they also affect aromatic compounds and flavor compounds. They make them more intense.”

Although researchers have only recently begun to study the impact of narrow light wavelengths on plant physiology, Kopsell said this will be the major use of LEDs in future applications.

“Not only is a grower going to be able to select the type of light and intensity from the LED manufacturer, but eventually the grower will know when is the critical time to apply a specific amount of light to a crop. One of the things that we have seen with these short term crops is using the light as a finishing-off treatment. The crops are grown under regular light conditions like any grower would have the ability to do and then just before harvest the plants would receive a specific type of light for a certain period of time. This light treatment would stimulate the plant physiology uptake and metabolism right before the plants go to the retail market.”

Kopsell said research exposing leafy brassicas to blue light prior to harvest has intensified pigments and green leaf color.

“We increased the green pigments in the leaves so that they looked more vibrant,” he said. “Other research has shown that UV light increases the anthocyanin compounds in leaf lettuce. Providing a little UV light, which is blocked out in most greenhouse environments, at the right time, a grower can get a crop to color up quickly before the plants are shipped out. What we have done with leafy greens to intensify the color of the leaves can also be done with petal tissue. By changing the light quality a grower could get more vibrant flower colors.”

Need for fine tune management

Kopsell said whether plants are grown outdoors, in a greenhouse or in a closed controlled environment with artificial light, the plants are using specific wavelengths from the available light source.

“Horticulture, floriculture and agronomic researchers know how much light is needed in order to produce crops with broad spectrum light,” he said. “The million dollar question that hasn’t been answered is how much light is needed from LEDs to achieve that same level of production? It is going to be less than the daily light integral (DLI) from a broad spectrum light source. But, right now we can’t tell you how much less it’s going to be.

“Applying specific light wavelengths when the plants need them, whether it’s for juvenile growth, flowering or fruiting, we don’t have a good grasp on the amount of light that the plants actually need. If a grower is only going to supply his plants with red and blue light, how much less light can a grower use in that production system?”
One of the reasons that plants will not require as much light from LEDs is because of the reduction in light stresses.
University of Tennessee studies have shown LED grow lights provide  a less stressful light environment for plants.

“Providing specific types of red and blue light, the amount of stress on plants is reduced because the plants don’t have to tolerate the light not being used for metabolism and physiology,” he said. “We have data that shows LEDs provide a less stressful light environment for plants. So we have to determine how much less light is needed. It is going to require an extra level of management to know what kind of light, how much light and when to apply it. Growers are going to be able to use LEDs to fine tune the light environment. It’s going to depend on the crop, how it’s being grown, where it’s being grown and how the crop will be used. Is it an ornamental, edible or medicinal crop? It’s not going to be as easy as sticking a seed or cutting into a substrate and letting Mother Nature take control. It’s really going to take some fine tune management. But the future looks bright so far.”


For more: Dean Kopsell, University of Tennessee, Plant Sciences Department, Institute of Agriculture, Knoxville, TN 37996-4561; (865) 974-1145; dkopsell@utk.edu.


David Kuack is a freelance technical writer in Fort
Worth, Texas; dkuack@gmail.com.Visit our corporate website at https://hortamericas.com

Plant factories continue to evolve

As technology improves, plant factories have the
potential to operate in the U.S. and Canada to produce crops that are difficult
to grow using current conventional methods.

By David Kuack
When you hear the term “plant factory” what picture comes
to mind? University of Florida professor and mechanical engineer John Schueller
said the traditional definition of a plant factory is a place in which there is
no natural light and artificial light is used to produce plants.
“I’m more of a traditionalist in that I feel a plant
factory is a place that has mainly or only artificial lights in order to grow
plants,” Schueller said. “But a greenhouse with multiple levels of plants in
which natural light is the dominant source and is supplemented with artificial
light, I would also consider that to be a plant factory.
“People involved in protected plant agriculture,
including greenhouses and indoor plant factories, are displaying a lot of
creativity. There are a lot of different systems being tried out. It’s
difficult to make a hard and fast definition of a plant factory. A traditional
greenhouse with plants on raised benches or growing on the floor is not usually
recognized as a plant factory.”
Plant factory

Schueller, who spoke at the Plant Factory Conference in
Kyoto, Japan, in Nov. 2014, said the most important automation that occurs in a
plant factory is during the growth stage.

“The application of light and fertilizer is when the main
automation occurs,” he said. “There is automation during planting when a grower
is trying to establish the plants. And there is also automation during

University of Florida mechanical engineer John
said the technology of plant factories
is improving with the main improvement
occurring with LED lighting.

courtesy of John Schueller, Univ. of Fla.

Schueller said during the Plant Factory Conference there
was a lot of discussion about which lights are the best for using in plant
“There are questions that still need to be answered about
what are the best wavelengths and what are the best cycles for different
crops,” he said “Even though there are a considerable number of plant
factories, we still don’t know what the optimal conditions are for growing
plants. There is a lot of variation and experimentation occurring.”
Schueller said automation in the plant factories will
probably occur with the planting practices before it happens with harvesting.
“In Japanese plant factories the finished plants are
brought to the harvesters,” he said. “There is automation to transfer the
plants. People are doing the harvesting of leafy greens, but they are brought
to the workers at an appropriate height and position so that they can be very
efficient and very productive. Obviously, if there are 14 layers of plants
under lights the plants are moved to the harvesters. But there is still some
human involvement in harvesting the plants.”
Schueller said an advantage to a plant factory is the
ability to precisely control the environment. “The technology is improving,” he
said. “The main improvement is with LED lighting. As LEDs become less expensive
and better that will help in the development of plant factories. Also, less
expensive sensors for measuring nutrient solutions are becoming available. As
growers gain more experience with this technology they get better at
controlling the production environment.”
Plant factory

Schueller said economics play a big role in what will be
feasible in how these factories operate.

“The Japanese market for fresh fruits and vegetables is
much different than in the U.S. and Canada,” he said. “In the U.S. and Canada,
vegetables are cheaper. The market will not bear some of the costs that will be
accepted in Japan. In Japan consumers are willing to pay $40 for a watermelon.
“From an agricultural economic standpoint, it seems to me
the big advantage of a plant factory is that a grower can control the
production situation very well. The disadvantages are the energy costs for
running the artificial lights and the capital equipment costs. The best
opportunity is to produce a product that has certain characteristics, that has
no pesticides applied, that has no bacterial contamination, so that a grower
can demand a premium price for it.”

Schueller said one area of plant factory production
that shows great potential
is being able to develop
techniques that allow high end vegetables to have
nutritional characteristics that can be easily manipulated.

Schueller said one area of plant factory production that
shows great potential is being able to develop techniques that allow high end
vegetables to have nutritional characteristics that can be easily manipulated
more so than in other production environments.
“One of the Japanese plant factories that was built by
Fujitsu is growing lettuce which has a low potassium content,”
he said. “This lettuce is being produced for kidney dialysis patients and
people with chronic kidney disease. This type of crop has a lot of potential
for U.S. and Canadian markets. Developing vegetables that have nutritional
characteristics so that the markets will be able to tolerate higher production
costs that are associated with plant factories.”
Schueller said the plant factories in Japan can produce
leafy green vegetables in about 15 days.
“The production cycle needs to be as short as possible,”
he said. “If a plant factory is controlled properly and maintains sanitary
conditions, it is possible to produce leafy green vegetables with specific
nutrient characteristics without pesticides. For those types of crops a grower
can demand a premium price to pay for the equipment and energy to produce
Fast, precise

Schueller said the plant factories in Asia are producing
primarily leafy green vegetables.

“I expect these crops would have the greatest potential
in the U.S. as well,” he said. “As more consumers move away from iceberg
lettuce and romaine lettuce, they tend to look for other types of lettuce and
leafy greens and microgreens. There might be real potential with these crops
because they can usually be turned much more quickly.”

has over 200 plant factories. One of the reasons that
the country has experienced
a proliferation of these facilities
 is food security. Sixty percent of the country’s
food is imported.

Schueller said some of the issues pushing plant factories
in Asia are related to domestic food production and land availability.
“Japan imports almost 60 percent of its food,” he said.
“For the Japanese it’s an issue of food security. Singapore has increased its
vegetable consumption from 7 percent to 8 percent. In Singapore there is a
limited amount of land. They are looking for ways to maximize food production
and plant factories offer them a solution. With plant factories that have
vertical farming they can push the production to maximize the space. In the
U.S. that isn’t a big concern. The plant factories in the U.S. that will be
successful are the ones that grow products that are difficult to produce using
conventional methods.”

For more: John
Schueller, University of Florida, Departments of Mechanical and Aerospace and Agricultural
and Biological Engineering; (352) 392-0822; schuejk@ufl.edu.

David Kuack is a freelance technical writer in Fort
Worth, Texas; dkuack@gmail.com.

Visit our corporate website at https://hortamericas.com

LEDs found to have multiple uses on multiple crops

Researchers at Purdue University are finding LEDs can
have positive effects on both ornamentals and leafy vegetables.

By David Kuack

As more research is done with light emitting diodes
(LEDs), scientists are discovering new ways to use the lights on ornamental and edible
plants. Researchers at Purdue University have done extensive studies on annual
bedding plants, comparing the growth of seedling plugs and vegetative cutting liners
under LEDs.
“My goal is to continue to do research with LEDs because
we are finding new and exciting results, especially with the indoor production
of young plants and microgreens,” said associate horticulture professor Roberto
Lopez. “Some of the work that we have been doing has shown the benefits of
“If you would have asked me two years ago if I would ever
try to produce plugs indoors and not in a greenhouse, I would have said no. If
you would have asked me five years ago if I would be working on greens or
vegetables, I would have said no. Now I am doing both of those things with

Purdue University graduate student Joshua Craven
and associate horticulture professor Roberto Lopez are
studying the effects LED
lights have on ornamental
plants and leafy vegetables.
Photo by Tom Campbell, Purdue University

No need for

Lopez and former graduate student Wesley Randall found
that greenhouse-grown seedling plugs of impatiens, marigold, petunia, vinca and
zonal geranium did as well or better when supplemented with LEDs compared to
plugs supplemented with light from high pressure sodium lamps. What Lopez found
surprising was the quality of the plugs produced in a growth room with LEDs as
the only light source.

“LEDs produce better plugs when they’re grown indoors
than when they are grown in a greenhouse with sunlight supplemented with light
from LEDs or high pressure sodium lamps,” Lopez said. “It is amazing how good
the plugs look grown in an indoor multilayer production system with LEDs. The
plugs are compact, sturdier and greener with a similar root and shoot dry mass
to greenhouse-grown plants supplemented with light from LEDs or high pressure
sodium lamps.”
One crop that Lopez said they are still “tweaking” with
LEDs is petunias.
“Petunias, which are long day plants, when moved from an
indoor grow room equipped with red and blue LEDs, encountered a slight delay in
flowering in the greenhouse,” he said. “We are going to see if exposing the
plants to far-red LED light prior to moving them into the greenhouse will
induce them to flower.”
Using LEDs to
intensify leaf, flower color

Lopez said many of the annual spring bedding plants grown
in greenhouses in northern climates are produced under low light levels. The
result is that some plants don’t produce the same intense foliage colors that
they would if they were grown outdoors.

“Plants grown in glass greenhouses are not exposed to the
sun’s ultraviolet light because it is blocked by the glass,” he said. “The
result is that crops like zonal geraniums and purple fountain grass (Pennisetum setaceum ‘Rubrum’) don’t
“color up” like they would outdoors. One of the things we noticed with zonal
geraniums was the dark patterns on the leaves stood out much more when the
amount of blue light was increased. We hypothesized and found it was a result
of an increase in anthocyanin production. We have also looked at geraniums that
have very dark foliage and found not only does leaf color darken, but flower
color can be made darker by exposing market-ready plants to red:blue LEDs.”
Lopez said the change in leaf color due to anthocyanin
production was also dramatic for purple fountain grass.
“Purple fountain grass is a very popular ornamental
species produced by many growers,” Lopez said. “Grown in the greenhouse, the
leaves appear to be dull green and not very purple. We found that putting the
plants under a combination of red and blue LEDs for one to two weeks of what we
are calling “end-of-production lighting” resulted in an attractive purple
color. UV light is what stimulates anthocyanin synthesis.”
He said in the case of purple fountain grass, only the
leaves exposed to the LED lights change color. Those leaves not exposed to the
LED light remain green.
Expanding studies
to vegetable crops

Seeing the positive results that occurred with LEDs and
purple fountain grass, Lopez and PhD student W. Garrett Owen expanded the
research to red leaf lettuce to see if they could produce a similar response.

“Trying to produce red leaf lettuce can be difficult for
greenhouse growers if they are producing crops under low daily light integrals
(DLIs),” Lopez said. “Growers producing red leaf lettuce under low DLIs are
essentially producing green lettuce.
“We placed red leaf lettuce under the same LED treatments
used for purple fountain grass and the plants colored up in three to five days.
Based on our research, red leaf lettuce and purple fountain grass can be placed
under a 50-50 red and blue LED combination prior to harvesting or shipping
triggering anthocyanin formation.”
on Purdue University research,
red leaf lettuce can be placed under a
50-50 red
and blue LED combination prior
to harvesting triggering anthocyanin formation
the lettuce‘s red color.
Photo courtesy of Roberto Lopez,
Purdue University
Based on the results related to LEDs and anthocyanin
formation, Lopez said the studies may be expanded to look at the impact of LED
light on ornamental cabbage and kale. “Growers, especially those in the South,
have a hard time coloring up ornamental cabbage and kale,” he said. “It is
primarily a temperature response, as the night temperatures get cooler the
plants start to color up.”
Lopez and Owen did a small study placing ornamental cabbage
and kale under LEDs that resulted in a minimal color change. When
greenhouse-grown plants were grown under cool night temperatures and exposed to
LEDs, they exhibited the most intense color.
“What we are proposing is for growers in warmer climates
who have access to coolers, is to use a cool temperature/LED treatment,” he
said. “We will be conducting this study next fall. Smaller container sizes like
4-inch pots, could be rolled on carts into a cooler and exposed to cool
temperatures and LED lights for three to four days prior to shipping enabling
the plants to color up.”

Another study conducted by graduate students Joshua
Gerovac and Joshua Craver looked at the effect of LEDs on the growth of three
different microgreen species (kohlrabi, mustard and mizuna) in an indoor
multilayer production system. The study included three different light
qualities and three different DLIs (light quantity).

“Overall what we have seen is as the DLI increases, this
is for three microgreen species we trialed, the length of the hypocotyl,
basically the height of the microgreen, decreases,” Lopez said. “The more light
the plants are provided, the more compact they are. If the plants received 6
moles of light, they were much taller than if they received 18 moles of light.
Depending on the growers’ market, some customers might want microgreens that
are a little leggier or they might want plants that are more compact. That will
depend on market preference.”
The ideal LEDs

Lopez said the ideal vertical LED light module would
contain all of the wavelength colors.

“The vertical LED light with all the different colors
would enable growers to turn them on when they need them and off when they
don’t, depending on the stage of plant growth,” he said. “Once flowering begins
a grower doesn’t want stem elongation. Far-red light works for flowering so the
far-red would be turned on for the minimum amount of time required for
flowering. If the grower wants to increase the amount of anthocyanin in the
leaves or flowers, he can turn on the red and blue light near the end of the
crop. To be able to turn on specific colors when a growers needs them, that is
something I envision happening with LEDs.”

For more:
Roberto Lopez, Purdue University, Department of Horticulture and Landscape
Architecture; (765) 496-3425; rglopez@purdue.edu;

David Kuack is a freelance technical writer in Fort
Worth, Texas; dkuack@gmail.com.

Visit our corporate website at https://hortamericas.com

Specialty Greens produces better crops with grow lights

Specialty Greens in Lafayette, Calif., is hydroponically
producing gourmet lettuces, herbs, chard, spinach, kale and microgreens. Owner Patty
Phaneuf has been working with Hort Americas to study the effects supplemental
production lighting can have on her lettuce and herb crops. She is using Philips
Green Power LED Production Modules Deep Red/Blue 120cm and T-5 fluorescent
lamps. T-5s produce light that is high in the blue light spectrum (440

Phaneuf said the lettuce grown under the LEDs and
fluorescent lights had accelerated growth and intensified leaf color. Using the
lights enabled her to produce the lettuce within a 30-day crop cycle from seed
to harvest.

Phaneuf was so pleased with the lettuce production
results that she is planning to expand the lighting trials. She is working with
Hort Americas to increase the amount of blue light given off by the LED
Production Modules so that she can eliminate having to use the fluorescent


For more:
Specialty Greens, www.specialtygreens.com.

Experiment information provided by Patty Phaneuf at
Specialty Greens. Posted by Maria Luitjohan at Hort Americas,

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Hort Americas is offering a Vertical Growing System

Hort Americas is working to help those interested in Vertical Farming develop their ideas.

One thing needed is a “system” that allows new growers to test their theories.  Hort America’s feels they have come up with an option.

Hort Americas has developed a Vertical Growing cart that allows the grower to set up a germination area and a finished plant area.  The customer can customize the Horticulture LED Grow Lights (referring to light quality and quantity), the planting intensities, the crops and the nutrient selection.

The Vertical Growing Cart is heavy duty and portable, giving the grower the flexibility to try different locations and systems.

For more information on Vertical Farming using these customized carts, please email Hort Americas at infohortamericas@gmail.com.

Photos of the First Cart designed to be shipped from the farm to the market using nutrient film technique, LED grow lights and organic fertilizers.

Heavy Duty and Portable Vertical Growing Carts

This cart using Nutrient Film Technique (NFT) 

Stock Tank(s), Germination and Finished Production in one area.

Artificial Lighting Provided by Horticultural LED Grow Lights

Visit our corporate website at https://hortamericas.com