Big Tex Urban Farms and Hort Americas have partnered together to install, test and demonstrate a variety of hydroponic production systems while at the same time providing Dallas community organizations with locally-grown produce.
Cornell University scientists have developed a computer program, Environmental Monitoring With an Agent-Based Model of listeria EnABLe, to simulate the most likely locations in processing facilities where the food-borne pathogen listeria monocytogenes might be found. Food-borne listeria infects about 1,600 people in the United States each year with about one in five of those infections ending in death.
Michigan State University researchers are studying the effects of sole source LED grow lights on edible and ornamental crops.
Michigan State University opened its Controlled-Environment Lighting Laboratory (CELL) in 2017. The 400-square-foot vertical farm research facility is being used to study the indoor production of high-value specialty crops, including edibles and ornamentals with LED grow lights.
Controlling the environment is a key component of preventing diseases on edible crops.
As an increasing number of growers start growing edible crops in controlled environment structures they may be facing some diseases that they haven’t encountered before. For ornamental plant growers who are adding edible crops, they will not have as many or as effective chemical controls as they have access to with their ornamental crops.
How you grow and process fresh cut basil will impact the flavor and shelf life of the harvested product.
Basil is one of the most popular culinary herbs. Whether grown as a potted crop or for fresh cut sales, basil is an herb that’s in demand year-round. Growers looking to add edibles to their product mix should consider basil to be a must-have herb in their product offerings.
Monitoring and collecting environmental conditions during controlled environment agriculture production can assist growers in making the best use of integrated pest management strategies.
While maintaining the proper temperature and humidity is important to ensure the optimum growing conditions for controlled environment agriculture, these environmental factors become even more important when using biological controls.
The Lighting Approaches to Maximize Profits (LAMP) project aims to determine how growers can maximize their return on investment when considering installing grow lights.
As light emitting diodes (LEDs) become more efficient and more affordable, an increasing number of greenhouse and plant factory growers will consider installing LED luminaires to light their crops. In the case of greenhouse growers, these luminaires would provide light to supplement natural sunlight. For plant factory growers, production depends entirely on the light provided by an artificial light source including LEDs, high pressure sodium or metal halide luminaires.
The use of supplemental light to control downy mildew on food and ornamental crops could be integrated into current disease management practices.
Downy mildew is a major disease on both ornamental and food crops. Whether these crops are grown outdoors or in a controlled environment, environmental conditions, generally cool to moderate temperatures and high humidity, are favorable to downy mildew development. Warm temperatures and high humidity are conducive to powdery mildew development.
Growers of ornamental and edible crops can use the 30MHz platform to capture and manage real-time data on crops and environments.
From cultivation to harvest, packing, processing and shipping, agri- and horticulture faces challenges that can be avoided with environmental and crop-level data. Real-time monitoring with wireless sensor technology empowers agribusinesses to look back on their crops’ history and current status, quickly respond to prevent a range of risks including disease, rot and sunscald and take proactive measures to ensure the highest quality, best flavor and most efficient use of resources. Developed with input from leading growers, the smart sensing solution offered by Dutch-founded agritechnology provider 30MHz makes it easy for growers to deploy wireless sensors and start capture the metrics most crucial to their operations in minutes, without technical expertise.
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.
Incorporating air or oxygen into irrigation water using nanobubbles can improve crop yields and reduce susceptibility to disease pathogens.
What started out as a way of making wastewater treatment systems more efficient with oxygen enrichment has expanded to how nanobubble aeration technology can improve production of agricultural crops. Moleaer Inc. in Torrance, Calif., filed a patent on nanobubble aeration technology in 2016 with the intention of using it as a way to deliver gas in a number of different applications.
When choosing horticultural lighting, growers need to consider lighting efficiency and how the lighting will be used.
There is a big difference between lighting efficiency for horticulture and lighting efficiency for consumer use. The difference is in who is receiving the light.
Whether growers are producing vegetables, ornamentals or other hydroponic crops, Hort Americas is working to provide its customers with the products and knowledge they need to be successful.
When Hort Americas in Bedford, Texas, started operating as a wholesale horticulture distributor in March 2009, the company had no existing customer base.
Increasing the oxygen level in the root zone can ensure healthy root growth and can impact crop yields.
Low oxygen levels in the growing substrate can play havoc with the health of both vegetable and ornamental plants. Shalin Khosla, greenhouse vegetable specialist at Ontario Ministry of Agriculture, Food and Rural Affairs in Harrow, Ontario, said a substrate oxygen level below 5 parts per million can have a negative effect on plant growth.
Sudlac shading products give greenhouse growers of flowers and vegetables the ability to increase and extend production during periods of warm temperatures and high light levels.
High temperatures and high light levels, especially during the summer can have negative effects on ornamental and vegetable crops produced in protected structures, including greenhouses. An economical way for growers to reduce light and temperature levels is by applying shading products to greenhouse glazing materials.
Incorporating dissolved oxygen into hydroponic production systems during warmer temperatures can help improve plant growth and reduce crop time.
Trying to grow hydroponic crops like leafy greens can be a real challenge during warmer times of the year. Growers have few options to lower temperatures, including cooling the greenhouse and/or water temperature. Another production technique that is being used by hydroponic growers in the United States and Australia is to introduce dissolved oxygen into the fertilizer tank solution.
“We’ve heard anecdotal reports that increasing dissolved oxygen levels can help prevent some root diseases like Pythium and other root rots,” said Tyler Baras, special projects manager at Hort Americas in Bedford, Texas. “We’ve also heard that increasing dissolved oxygen can possibly improve nutrient uptake and improve overall growth. Another possible benefit with using dissolved oxygen is reducing tip burn on leafy greens.
“These are some of the main issues with growing in warm climates like Texas during the summer. With an increase in water temperature comes a higher disease pressure and chances for tip burn. This has occurred in both nutrient film technique and deep water culture systems.”
The optimum water temperature for lettuce is between 65ºF-70ºF. For basil the optimum water temperature is around 75ºF.
Baras said most of the references he has read for adding dissolved oxygen suggest incorporating 4-10 parts per million for leafy greens.
“Most growers that I know are adding between 6-7.5 ppm for leafy greens,” he said. “When growers start to go beyond that rate to reach a higher level they have to use something like compressed oxygen or ozone. These are the main two methods, which are more expensive, for achieving a higher dissolved oxygen rate. Most growers I know are using a less expensive Venturi system or an air pump with air stones to add dissolved oxygen.”
Trialing different levels of dissolved oxygen
Baras has been studying the impact different dissolved oxygen levels can have on butterhead lettuce, basil and arugula grown in deep water culture systems. He set up deep water culture systems with three different levels of dissolved oxygen: 2 ppm, 7.5 ppm and 29 ppm.
“We have been tracking growth and how it affects the morphology of the plants,” he said. “The 2 ppm dissolved oxygen rate is what we were able to achieve without doing any type of aeration. This was our control.”
In another system Baras used a Venturi attachment to a small submersible pump that drew in atmospheric air.
“The highest rate of dissolved oxygen that we could achieve using atmospheric air was a maximum of 8.5 ppm,” he said. “The rate hovers between 7.5 to 8.2 ppm, with it usually averaging 7.5 ppm.”
The third system is a high rate of dissolved oxygen that uses compressed oxygen tanks to deliver 29 ppm.
“This system uses nanobubble technology,” he said. “We were using a prototype device that forces oxygen into a solution in really small bubbles so that the oxygen stays in suspension longer instead of falling out. The lowest rate that we could set was 29 ppm. This level of dissolved oxygen is much higher than what most leafy greens growers are targeting.
“A lot of the flowering crop and cannabis growers who are incorporating dissolved oxygen are actually targeting these higher rates. These growers are achieving 20-40 ppm dissolved oxygen. The flower and cannabis crops tend to prefer to be grown on the dry side. With this type of nanobubble dissolved oxygen technology it opens up this production method to crops beyond leafy greens.”
Some dramatic results
Baras said he has seen some dramatic effects on plant growth with higher dissolved oxygen rates. At the beginning of the trials during the first month the water temperature in the fertilizer tanks was 80ºF. During the second month the water temperature was between 75ºF-80ºF.
“At 2 ppm the arugula plants were severely stunted and were unsalable,” he said. “At this low rate there were also some severe nutrient deficiencies. At 7.5 ppm the arugula looked normal with slight deficiencies. There weren’t any nutrient issues at the 29 ppm rate and the plants almost doubled in size.”
Baras said even at the low rate of 2 ppm some crops could still be marketable.
“The basil and butterhead lettuce could still pass as marketable at the low 2 ppm rate,” he said. “The plants were very small and it would take several more weeks of production to reach the target weights we were aiming for. At the 7.5 ppm dissolved oxygen rate the plants had fairly normal growth as to what we are used to seeing.
For butterhead lettuce at the 2 ppm rate the heads were smaller and compact. The core of the heads were tighter, but actually had a good shape. At the 7.5 ppm and 29 ppm rates, the heads had similar shapes.
For the basil there was an increase in height as the dissolved oxygen level increased. Overall the plant height and size increased at higher dissolved oxygen rates.
“At the 29 ppm rate, the plants looked like the plants at the 7.5 ppm rate, but they were about a week ahead,” Baras said. “Both of these rates produced plants with healthy looking morphology, but the plants receiving 29 ppm dissolved oxygen developed faster. On average all of the crops grown with 29 ppm were at least a week faster to finish to a marketable size.”
Differences in root growth
Baras said the roots for the crops in the three rates of dissolved oxygen had different growth patterns.
“The roots in the 2 ppm dissolved oxygen systems were very short and stubby and almost seemed to be retreating from the water,” he said. “The roots remained mostly in the stone wool rooting cubes.”
At the 7.5 ppm dissolved oxygen rate the roots were long and had a lot of lateral branching. Baras said they looked like standard hydroponic roots.
“At the high 29 ppm rate the roots actually had less lateral branching, but they were really white, long and thick,” he said. “But there was less lateral branching. It almost seemed like since there was so much oxygen in the water the plants didn’t need to have as much lateral branching.”
Even though there were differences in the root morphology, there was no significant difference in the root weight for all three dissolved oxygen levels. The average root weight for both the 7.5 ppm and 29 ppm rates was 0.8 ounces. The root weight for the 2 ppm rate was about 0.7 ounces.
For more: Hort Americas, (469) 532-2383; firstname.lastname@example.org; https://hortamericas.com.
David Kuack is a freelance writer in Fort Worth, Texas; email@example.com.
Trials with organic and conventional fertilizers in hydroponic production systems are showing it’s possible to produce edible crops at much lower nutrient levels.
How much different is it growing edible crops organically than it is with conventional production inputs? Hort Americas special projects manager Tyler Baras is studying the differences in trying to grow organically versus using conventional production methods.
Baras has been doing organic production research in a 12,000-square-foot greenhouse in Dallas, Texas, using four deep water culture ponds and a nutrient film technique system. The ponds measure 4-foot by 8-foot and are 10 inches deep. Baras said the ponds are smaller than what would be found in many commercial greenhouse operations, but said the pond size is common in vertical farm setups. Baras has been trialing commercial organic fertilizers including Pre-Empt and an experimental organic fertilizer. The organic fertilizers are being compared with crops grown with Hort Americas 9-7-37 hydroponic fertilizer with calcium nitrate and magnesium sulfate. All of the production systems have also been incorporated with the commercial microbial inoculant TerraBella. Crops being grown in the production systems include Italian basil, green butterhead and red butterhead lettuce.
Rethinking optimum nutrient levels
Baras said the deep water culture production results he has gotten with Pre-Empt organic fertilizer have been comparable to the crops grown with the conventional Hort Americas hydroponic fertilizer.
“With Pre-Empt we have been able to match the growth rates of the conventional salt fertilizer,” Baras said. “As a result of the growth rates we have gotten with the organic fertilizer, we have started to question the nutrient recipes that have been recommended for hydroponic edible crop production. Many of the traditional recipes for hydroponic production have a target level of 200 parts per million nitrogen. But we are seeing the same growth rates in the organic fertilizer ponds with 10 ppm nitrogen as the 200 ppm nitrogen conventional fertilizer pond.”
Baras said the electrical conductivity level in the organic fertilizer ponds has been as a low as 0.5 compared to 2.5 in the conventional fertilizer pond and the crops are coming out nearly identical in terms of production time and plant weight.
One difference between the organic- and conventional-grown crops is the time in propagation.
“The crops are finishing at the same time from transplant to harvest time, but we are keeping the plants an extra week in the seedling stage for the organic fertilizer,” Baras said. “We are running the seedlings for two weeks with the conventional fertilizer and about three weeks with the organic fertilizers.
“The organic plugs are started a week earlier, but they are transplanted on the same day as the conventional plugs. We want the roots coming out of the side of the plugs before we transplant them into the ponds. The seedlings are fairly similar in size when they are transplanted into the ponds.”
Once the organic and conventional plugs are placed into the ponds, they both spend the same amount of time there until the crops finish.
“The plants are coming out of the ponds with nearly identical weights,” Baras said. “Overall the seed to harvest time is faster with the conventional fertilizer, but that it is because we are able to transplant the plugs into the pond faster because the roots are coming out of the plugs sooner.”
Baras said the plants grown with the organic fertilizers have also shown they can be grown with lower levels of other nutrients. For example, with the conventional fertilizer the nutrient solution may contain 200 ppm potassium and the level is only 12 ppm with the organic fertilizers.
“Aquaponic growers have seen similar situations,” he said. “Some aquaponic growers may be running an EC of 0.7 with a relatively low nutrient level, but they are still seeing good growth.
We are seeing that as well with the organic fertilizers. There are low nutrient levels in the solution, but the crops are coming out the same and the leaf tissue analysis is nearly the same as well.
“For our trials the macronutrient uptake for the plants, even when they are grown in a low fertilizer concentration like 0.5 EC, they are still able to pull what they need out of the solution. Leaf sample analyses of butterhead lettuce and Italian basil grown in 0.5 EC organic fertilizer vs. 2.5 EC conventional fertilizer, most of the macronutrient levels in the leaves are very similar. It appears the plants are doing a good job of regulating the nutrient uptake to get what they need.”
Aging fertilizer solutions
Baras said letting the organic fertilizer solutions age in the ponds may have an impact on the availability of nutrients for some crops. The aging of the fertilizer solutions also has an impact on increasing the microbial population.
“We have definitely seen some differences in plant growth,” he said. “Our first crops of butterhead lettuce and basil did very well with Pre-Empt organic fertilizer. However, one of the other organic fertilizers we trialed grew a quality first crop of lettuce, but not the best looking basil. As we continued the trial with our second and third crops, the basil grown with the other organic fertilizer started doing much better. It appears the organic solutions in the ponds may need to age until the nutrients reach adequate levels.
“This is what we were seeing in a 9-month old Pre-Empt pond vs. a 2-month old Pre-Empt pond. A lot of nutrients have accumulated in the 9-month pond and are approaching the recommended nutrient levels that would be found in a conventional fertilizer system. Organic fertilizers like Pre-Empt don’t have a lot of magnesium in them. However, when the fertilizer is run in a pond system for 9 months the magnesium level rises and approaches what would be considered a conventional fertilizer target level for magnesium.”
Aging of the fertilizer solution also has had an impact on the root growth of the crops.
“When we compare how the roots look visually in the 9-month solution vs. the 2-month solution, the roots in the 9-month solution look much healthier,”Baras said. “The roots are very white, are longer and look really healthy and well-developed. There are also more roots on plants in the 9-month system.
“The root color is also significantly different. In the 2-month solution the roots look healthy, but there is some browning. They don’t have that crisp white look.”
Rethinking optimum pH levels
Baras said he has been able to produce healthy crops in a pH range from as low as 4 up to 6.5.
“For hydroponic leafy greens the recommended pH ranges from 5.5 to 6.5,” he said. “We have basil and butterhead lettuce growing very well in organic systems at a pH of 4. On the other side of the pH range, I’ve heard of aquaponic growers growing these crops at a pH up to 7 without any problems. Based on our trial results some of the conventional recommendations for hydroponics for both pH and nutrient levels might need to be revisited.
“One of the biggest issues I see with hydroponic growers is overcompensating. For instance, they feel that they need to be constantly watching the pH. They may set up monitoring and dosing systems to ensure the pH doesn’t go below 6 or 5.5. They are investing in extra equipment because they think they need to keep the pH precisely in this range. It may be a case that the plants will do well outside this range.”
Impact on crop timing
Baras said one factor that could affect the optimum pH and nutrient range is the light level.
“If a grower is providing supplemental light, then the optimum pH and nutrient range may be different,” he said. “With the trials we are conducting we aren’t that far off from what most hydroponic growers are targeting for growth rates. Thirty-five days is a target number for a lot of lettuce growers. We have done 35-day crops. We want to be able to grow an organic crop in the same amount of time as a crop grown with conventional fertilizers.”
For more: Hort Americas, (469) 532-2383; firstname.lastname@example.org; https://hortamericas.com.
David Kuack is a freelance writer in Fort Worth, Texas; email@example.com.
Controlled environment agriculture growers have been trying to fit a square peg into a round hole by growing field crops in indoor environments. This is changing as research tries to match plant genetics with the production environment.
During this year’s International Congress on Controlled Environment Agriculture (ICCEA) in Panama City, Panama, University of Florida horticulture professor and keynote speaker Kevin Folta discussed the overlooked reality that food crop varieties have not been bred for indoor controlled environment production.
“One of the limitations of controlled environment agriculture (CEA) is that the conditions do not match the genetics,” Folta said. “Plants being grown in CEA environments were actually developed for field production. There are a lot of opportunities that go unrealized by growing plants in a controlled environment. It’s like asking Chihuahuas to pull a dog sled. Plants that were bred for one application are expected to perform under very different applications. The genetics don’t match.”
Creating the next generation of plants
Folta said research has begun to develop the next generation of plants with the potential to develop different products using the same set of genetics by changing the environment.
“By flipping a switch and varying the light spectrum we could change green leaves to purple or have the plants accumulate specific flavors or textures or nutraceutical compounds,” he said. “That is all very realistic. This is like being able to shine a different light spectrum on a Chihuahua and turning it into an Alaskan malamute or a dachshund. A plant’s body, its composition, its chemicals, its secondary metabolites could be altered by changing the light environment. We need plants that are ready to do that. We need to identify or create those genetics.
“We are exposing plants to different light spectra and evaluating how the plants behave and perform. Then we will work with plant breeders to develop the next varieties.”
Need for more industry involvement
Folta said the companies that are developing and manufacturing the lights for CEA production should become more involved with the development of plants grown in these environments.
“The lighting companies should be working with the university researchers and plant breeders,” he said. “The lighting companies should be financing the development of proprietary varieties. Unfortunately that hasn’t been an area of interest for the lighting companies. They want to make and sell lights. They forget the seed. The seed is a much more complicated machine.
“The lighting companies should be able to say to the growers here are the grow lights we are offering and here are the seeds that grow best under them. That opens up recurring revenue for the lighting companies. It behooves the lighting companies to focus on identifying plants that perform best with their products. It’s like saying that a Ford engine does best with a Motorcraft oil filter. It’s manufacturer’s optimized matching parts.”
Folta said plants are the most complicated part of matching the genetics with the environment and the part that people worry least about.
“It doesn’t matter whether the breeding company or the lighting company takes the initiative to develop the genetics,” he said. “This is going to happen whether it’s private plant breeders, universities or technology companies. This is another niche to create new genetics. You’ll see people filling this void.”
Limiting, changing the production environment
Even technology companies like Panasonic, Toshiba and Fujitsu are finding opportunities in controlled environment agriculture.
“These types of companies will develop the genetics or will find the genetics that work well in CEA environments,” Folta said. “For now the field genetics will continue to be put in artificial conditions and the indoor environment will be reshaped to accommodate the plants. What should be done is finding or developing plants for these energy-efficient, artificial conditions that are sufficient to support growth. Research needs to be done to determine how to maximize output or yields with fewer photons of light or colors of light. Research is going to focus on economic viability. I expect the pharmaceutical companies will get involved in this research.
“My interests are much more about food and how we create the next generation of profitable growers and higher nutrient crops that are more readily available for consumers. That’s what gets me fired up.”
While matching the genetics to fit the environment is important, Folta said researchers also need to be looking at limiting the environment.
“At the same time that we are looking at the breeding and genetics, we are also looking at how we can deliver shorter pulses of light that still maintain the same output,” he said. “We have cut energy application by 50-80 percent and grown comparable products. The viability of these systems has come from people who have focused on the diminishing return of light efficiency. What they need to work on is the plant efficiency. That is something that is extremely viable.”
Folta said all of the research he has been focused on is with small format, high value crops, including lettuces, sprouts and microgreens.
“Our university does not have the facilities to conduct the necessary experiments,” he said. “But we are partnering with others to do that. We will have good access to larger spaces in the upcoming months. It’s less likely that this type of production would be done with crops that take more space like melons. We are looking at plants where the vegetative portions of the plants are eaten. If you consider a head of lettuce, every photon that is invested results in the plant structure. With a crop like tomatoes, 80-90 percent of the biomass is being thrown away or composted.
“Growing the plants in shorter production times, shorter supply chains, better postharvest quality because of shorter supply chains, possibly lower costs, a lower carbon footprint and access to local markets, these are the issues I want to address. I see this being done with lettuces, microgreens and herbs such as cilantro and basil. Not so much with corn or melons where a huge amount of energy is invested in a relative small return in terms of calories. These types of crops do better using the sun.”
Folta said 15 years ago people thought the idea of light recipes and changing the spectrum was a crazy and senseless idea.
“Researchers and light manufacturers thought mixtures of red and blue light were all that was needed to grow plants in controlled environments, so there wasn’t any concern about doing anything different,” he said. “Now people understand that green, far red and UV light have important roles and that light quality should change throughout the day. With that in mind, it gives us some flexibility when it comes to changing the production environment, which is a really good thing.”
For more: Kevin Folta, University of Florida, Horticultural Sciences Department, Gainesville, FL 32611; firstname.lastname@example.org; http://www.hos.ufl.edu/faculty/kmfolta.
David Kuack is a freelance technical writer in Fort Worth, Texas; email@example.com.
Tour of Hort Americas research and demonstration greenhouse in Dallas will show growers different hydroponic production systems for various vegetable crops.
Growers of hydroponic vegetables or those considering starting growing vegetables hydroponically should plan on attending the AmericanHort Production Technology Conference. Scheduled for Oct. 9-11 in Dallas, the conference begins with a Technology in Action Tour on Oct. 9 which will visit three local production operations: Hort Americas research and demonstration greenhouse, Seville Farms and Southwest Nursery.
All things hydroponic
Hort Americas, a horticulture and agriculture wholesale supply company, has retrofitted a 12,000-square-foot floriculture greenhouse for the hydroponic production of vegetable crops. Tyler Baras, who is the special projects manager at Hort Americas, is overseeing the trialing of five different production systems along with the testing of potential products for the company’s online catalog. The production systems include: nutrient film technique (NFT), deep water culture floating raft, a vertical hydroponic tower system, a flood-and-drain vertical rack system and a new capillary mat manufactured in Europe. The greenhouse is being used to grow a wide variety of lettuces, leafy greens, herbs and microgreens.
The NFT system uses a new channel design. Baras said the narrower channels allow for the aging of crops without having to physically move plants from nursery channels to finishing channels.
Hort America’s main floating raft deep water system is an in-house custom design that measures 32-feet by 28-feet.
“We have tried using a Venturi system to incorporate oxygen, but for the last two months we have been doing trials with compressed liquid oxygen,” Baras said. “We have been doing trials to see how plants respond to increased levels of dissolved oxygen. This deep water system hasn’t been flushed in over a year.
“We have been managing the nutrient solution with water tests and individual salts. Instead of using a standard N-P-K fertilizer like we have been using in the other production systems, we have really focused on water tests and making nutrient adjustments based on those tests. We have been trying to keep the nutrients within a target range and trying to run the system for as long as possible without having to flush any of the nutrient system. We are testing for all of the essential nutrients. We are also looking at sodium chloride levels and seeing how those accumulate. Also, we are tracking what essential nutrients accumulate over time and how we can adjust the fertilizer being added to accommodate the natural accumulation in the system.”
Baras is also studying how the water source can contribute to the nutrient level.
“We are considering how source water may be a limitation to applying this no-flush technique,” he said. “Our source water is municipal water, but it has a high sulfur content of about 44 parts per million. So we are looking at cutting out all sulfur inputs. We are learning the challenges of trying to manage a no flush system.”
In addition to the main deep water system, Baras said tour attendees will also see several smaller deep water culture systems.
“In these smaller deep water culture systems we will be showing the use of three different organic fertilizers where we are comparing the growth between them,” he said. “We will also be showing a smaller scale deep water culture system receiving aeration compared to one with no aeration.”
Vertical production systems
Another hydroponic system that Baras is working with is a vertical tower commonly used by smaller growers.
“We have a lot of customers who use this system so we decided to install one in the greenhouse so we could look at some of the issues that they are dealing with,” he said. “We also were looking to answer some of the questions that our customers had about using the system. An example is can this system be used to grow organically? We’ve done both organic and conventional trials with this system.
“We’ve also been looking at what crops perform best in this vertical system. We’ve done a lot of variety trials as well as with the other systems we’ve installed.”
Hort Americas is also trialing a vertical Growrack from Growtainer.
“This is a flood-and-drain vertical rack system,” Baras said. “The rack has three levels, but it could be expanded. The rack has a 2-foot by 5-foot footprint. We have equipped it with GE LED lights. This would be the type of system used in a vertical farm setup.”
Baras said the Growrack system, which is set up in the greenhouse, has done well in warm conditions because its water reservoir is below the rack.
“The reservoir is usually stored underneath the racks so it is in shade,” he said. “The water isn’t always in the trays so it doesn’t collect the heat from the trays. It works well in warm climates.”
Although Baras has grown full size crops in the Growrack, it is being used now primarily for seedling propagation.
“The focus of the system is how it has enabled us to cut back on the amount of space that is needed for propagation,” he said. “We can easily grow enough seedlings in this system for a 10,000-square foot greenhouse.
“The system is also being used by a Central Market store in Dallas to finish crops for its Growtainer farm. We helped consult on the management of the system and showed store officials how it could grow crops from start to finish in the same Growracks. The store is growing fully mature butterhead lettuce and basil in the system. This system can definitely work in indoor vertical farms.”
Baras said he has grown both organically and conventionally with the Growrack system.
“We have done organic seedling propagation in it,” he said. “We have used a variety of conventional and organics substrates and fertilizers with it.”
In addition to trialing LED lights vs. natural light for greenhouse seedling propagation and crop staging, Baras said he is also looking at using LEDs supplemental light throughout the production of butterhead lettuce in the floating raft system.
“We are looking at how LED light affects leaf texture and plant morphology of butterhead lettuce,” he said. We are trying supplemental lighting during the summer. We are pulling shade so the light isn’t very intense. It appears that intense light can lead to tip burn that damages the plants leading to a poor quality crop. So we pull shade cloth and then run a prototype high-output LED grow light provided by GE for almost 20 hours. We deliver a low intensity of light over a longer period so we can provide the plants the light they need without stressing them. We are trying to improve the quality by adding LED light in order to produce more compact growth that is associated with LEDs.
“Under greenhouse shade cloth the lettuce leaves look fragile. We are trying to grow the lettuce to hit a certain weight. If the plants are grown under shade they look fairly large and floppy and the head doesn’t have the right density at its core. By using the LEDs we can produce the more traditional morphology where the plants have a dense core. The leaves aren’t floppy and the plants look more like traditional butterhead should look.”
Matching plants and production systems
Baras said he is trialing a wide range of crops in all of the production systems he is using.
“Primarily we are focused on lettuce and basil, but we are trialing a lot of varieties,” he said. “We definitely see some systems are capable of growing some varieties that other systems are not. We want to be able to recommend what varieties grow best in what systems. We are preparing a book based on our research that will include an entire section on strategies for how to use these production systems. We will provide example situations in the book discussing location, climate, market, what crops are being requested by that market and how to use that information to determine what production system is most appropriate.
“We are looking at primarily butterhead, romaine and oakleaf lettuce and 20 different basil varieties. We are also doing trials with arugula, spinach, cilantro, kale, chard, Asian greens and microgreens. We are doing an extensive study of herb varieties. There are also some unusual crops like stevia, wasabi arugula, celeriac and sorrel. We are determining all of these plants growth habits in the different production systems. This information will be in the book along with the details and nuances of growing each crop.”
Based on the trial results, Baras said the book will provide details on each plant variety and its performance in each system.
“The book will provide information on the growth a grower should expect in different environments based on the amount of light and temperature,” he said. “The book will offer projected production numbers a grower should be able to reach. These will be realistic targets for each of the production systems we have studied.”
For more: Hort Americas, (469) 532-2383; https://hortamericas.com.
David Kuack is a freelance technical writer in Fort Worth, Texas; firstname.lastname@example.org.