As a follow-up to Indoor Ag-Con Trend Report One issued earlier this year, below are some of the latest trends shaping the indoor agriculture industry today and a selection of product highlights from Indoor Ag-Con 2024 exhibitors.

Climate Control
In recent years, climate control has emerged as a pivotal trend in indoor agriculture, revolutionizing the way crops are grown in controlled environments. With a heightened focus on sustainability and food security, growers are increasingly turning to sophisticated climate control systems to optimize growing conditions regardless of external weather patterns. These systems integrate advanced technologies such as sensors, automated ventilation, and LED lighting, to create tailored environments that mimic ideal growing conditions. By fine-tuning factors like temperature, humidity, CO2 levels, and light intensity, indoor farmers can achieve higher yields, faster growth cycles, and superior crop quality while conserving resources and minimizing environmental impact.

Groupe Eode, (Booth 1306) in partnership with ECU Plus, ATC, and GPS, offers a comprehensive precision climate solution, assisting growers in increasing yields while minimizing risks and energy costs. The ECU plus is a new product line offering a HVAC system capable of delivering the most precise temperature and humidity control in the industry, with exceptional energy efficiency. GPS is a new product line reducing and controlling mildew and pathogen by generating ions in the space. Cost effective and without any maintenance or replacement parts.

Hoogendoorn Growth Management’s (Booth 600) flagship product, IIVO, is a revolutionary climate computer equipped with Intelligent Algorithms, streamlining greenhouse management. IIVO not only simplifies climate optimization but also stands out with proactive Intelligent Algorithms that continuously fine-tune climate control based on forecasted weather conditions, ensuring peak efficiency in greenhouse operations.

Microclimates (Booth 701) is an innovative technology firm specializing in environmental automation tailored for the controlled agricultural sector. In an era where automation systems often operate independently, lacking seamless communication, Microclimates introduces a groundbreaking solution. Unlike traditional siloed approaches, the platform transcends hardware dependencies, providing a unified ecosystem. Through the platform, disparate systems—ranging from climate control and lighting to irrigation and fertigation—are seamlessly integrated onto a single user-friendly interface, facilitating harmonized data management and optimal operational efficiency. Microclimates partnered with Veea Inc. to launch LoRaWAN (Long Range Wide Area Network) as the wireless solution for sensing and controlling and its low price point allows for easy deployment in any facility.

DryGair (Booth 207) develops and manufactures a patented dehumidification solution for commercial-scale horticulture, including greenhouses, nurseries, indoor grow rooms, drying rooms, and more. DG dehumidifiers combine powerful and efficient dehumidification with a unique air circulation mechanism to ensure uniform, optimal conditions in the grow space.

DesertAire (Booth 1305) offers highly efficient, purpose built integrated HVACD equipment specifically designed for indoor agriculture. Desert Aire’s GrowAireTM GreenAireTM and DriCureTM HVACD solutions provide integrated HVAC control of temperature and humidity in order to provide stable VFD to enhance and protect crops. The new Chilled Water Integrated HVACD System for CEA will be shown at Indoor Ag-Con.

FabricAir (Booth 702) provides complete air solutions for indoor farming and vertical grow operations. Their fabric-based air delivery systems are custom engineered to prevent microclimates, facilitate uniform temperature and humidity within the grow space, and allows plants to flourish through every stage of the grow cycle. FabricAir ducts are lightweight, hygienic, washable, and they don’t condensate which eliminates corrosion issues. The Rack Flow system offers custom designed airflow solutions for
multi-tiered grow spaces.

A new partnership between Wageningen University & Research and Skytree (Booth 903), focuses on the use of direct air capture (DAC) technology in the Dutch horticulture industry. The project aims to explore how DAC-generated CO2 can affect plant growth, the energy efficiency of producing CO2, and the optimal integration of DAC into existing greenhouses.

• Quality: The project investigates the impact of DAC-generated CO2 on plant growth, which is crucial for greenhouse quality improvements.
• Energy: It measures the energy required to produce 1kg of CO2, a key factor in the sustainability of greenhouse operations.
• Integration: The research focuses on optimizing DAC integration, which is essential for modernizing greenhouse infrastructure.

Learn more at Indoor Ag-Con!

MJ-Tech (Booth 320) is a leader in providing high-pressure fog systems, from breeding to propagation and/or cultivation. To manage humidity, to have adiabatic cooling (lower temperatures) all in the most flexible way with your overall climate computer steering..

Smart Irrigation
Irrigation in indoor agriculture has undergone a notable transformation, driven by advancements in technology and a growing emphasis on sustainability and efficiency. Traditional irrigation methods, such as flood and drain systems or hand-watering, are being replaced by more precise and automated techniques. Hydroponic and aeroponic systems, utilizing nutrient-rich solutions or misting mechanisms, have gained popularity due to their ability to deliver water directly to plant roots while minimizing waste. Moreover, the integration of sensors, data analytics, and smart controls enables growers to monitor and adjust irrigation schedules in real-time, optimizing water usage and crop health. This shift towards precision irrigation not only conserves water, but also enhances crop yields and quality in indoor farming environments.

Dramm (Booth 613) is pleased to announce their partnership with CE-Line to provide in-line nutrient testing to irrigation water in North America. CE-Line is a unique, laboratory quality, nutrient analysis system that automatically samples water throughout the day. This in-line testing solution provides accurate data within an hour, eliminating the wait for test results from a remote laboratory. Sample results are securely stored in the cloud with APIs available to connect to your climate control and fertigation systems. This connectivity allows for automated optimization of nutrient levels in real-time.”

In the Controlled Environment Agriculture (CEA) sector, Siemens’ (Booth 1400 and 1501) advanced controls systems, innovative infrastructure, and building automation systems empower growers to optimize crop growth, conserve resources, and increase yields—all while harnessing the power of automation and data-driven insights—leaving customers more sustainable, from the field to the table.
FGM USA (Booth 321) offers automated NFT growing systems including all irrigation and water treatment systems, as well as a propagation/vertical grow systemmanufactured by FGM. FGM a Danish and USA Company is a leading designer and mfg. of horticulture equipment since 1979.

HANS® (Booth 1522) has reinvented every component used to treat water – from the
redundant pump to reverse osmosis elements into intelligent, efficient, space-saving
devices. They are designed to work together in modular, scalable systems to meet
every need. So even if your customers have brackish water, or need de-ionized water,
or use a million gallons per day, HANS components can be assembled to get the job
done – quickly, easily and effectively.

Super Food
Indoor agriculture presents a promising avenue for exploring alternate food sources, particularly in the realm of sustainable and innovative farming practices. Vertical farms, hydroponics, and aquaponics systems are just a few examples revolutionizing how we grow food. These methods not only maximize space but also offer opportunities to cultivate unconventional crops like microgreens, edible flowers, and specialty herbs. As indoor agriculture continues to evolve, it provides a fertile ground for experimenting with diverse food sources, offering resilience against climate change and bolstering food security for future generations.

Pure Life Carbon (Booth 1222) is a private Canadian clean AgTech firm that has developed the first re-usable, carbon sequestering, soilless growing medium for the controlled environment agriculture market. The products utilize Advanced Carbon technology to solve problems for growers that were unsolvable in the past. Pure Life Carbon is among a high-performing group of global innovators and visionaries working to feed the populations of tomorrow while healing the environment. Pure Life Carbon has developed the first re-usable, carbon sequestering, soilless growing medium for the controlled environment agriculture market.

Klassman-Dielman’s (Booth 812) focus will be on the presentation of a genuine innovation for modern horticulture: Nygaia. Nygaia is a new and groundbreaking substrate fiber based on biopolymer technology that is biodegradable and is particularly suitable for use in hydroponic systems. Under the theme “The magic of innovation,” the completely newly developed, innovative substrate solution will be brought to life with plant examples grown in Nygaia, test kits distributed to interested guests at the
Klassman-Dielman booth or with the appearance of magician Rob Anderson during the Indoor Ag-Con Expo Floor Day One Cocktail reception!

Royal Gold (Booth 505) is the Original Coco soils company, pioneering Coconut based soils and growing mediums for nearly 2 decades. They are leaders in quality and consistency in the marketplace and focus on industry leading customer support for both hobby and commercial cultivation of all crops. Featuring a variety of soils and soilless mediums and offering OMRI/CDFA organic fertilizers and amendments, Royal Gold is the gold standard in gardening. They will be displaying the new All-purpose fertilizer and new 70/30 Coco-Perlite Blend as well as sharing information on its forthcoming Planting Mix and Potting and Propagation Mix.

BIO520 (Booth 1212) is an all-natural essential liquid mineral nutrient for optimal plant cultivation. Derived from a combination of ancient volcanic magma and sea sediments, and free of any harmful chemicals, BIO520 contains an abundance of vital minerals to help plants thrive. BIO520 is beneficial for all plants and crops, indoor or outdoor. Developed from Mother Nature for Mother Nature.

NGS (Booth 1023) manufactures hydroponics for Strawberries, Lettuces and Leafy Greens. NGS is an engineering firm which has been developing automated systems to optimize growing production both by reducing labor and by incrementing production. NGS builds greenhouses that grow lettuce in the desert as well as indoor systems for strawberries. NGS is presenting its patented rotational system for strawberries which doubles normal tabletop production. This new system is revolutionizing the way
strawberries are being grown while reducing labor and production costs.

Supreme Perlite (Booth 1216) horticultural perlite products are the ideal indoor, CEA, or hydroponic growing media made here in the U.S.A from domestic raw material sources. The products are sterile, 100% natural, non-toxic, lightweight, pH neutral, durable and insulating. Used as a standalone product, expanded perlite offers clear advantages such as excellent capillarity, water-holding capacity, and air-filled porosity. Combined with other media, perlite boosts drainage rates and aeration, holds moisture and nutrients close to roots, and resists compaction as other substrates begin to break down.

EPM (Booth 521) stands at the forefront of eco-friendly plant protection, manufacturing natural solutions in the USA. They excited to debut a 3in1 plant wash, ECO Green, an innovative solution that cleans plant leaves, roots, and acts as an effective pest management alternative. Its unique blend of catalytic enzymes and citric acid not only removes dirt and biofilm but also guards against pests.

For more information on the 2024 exhibitors, please visit www.indoor.ag.

ABOUT:
Founded in 2013, Indoor Ag-Con has emerged as the largest trade show and conference for vertical farming | greenhouse |controlled environment agriculture. Its events are crop-agnostic and touch all sectors of the business, covering produce, legal cannabis | hemp, alternate protein and non-food crops. More information, visit www.indoor.ag

PhD instructors include Paul Fisher from University of Florida, Erik Runkle and Roberto Lopez from Michigan State University, Jim Faust from Clemson University, John Erwin from University of Maryland,
Jennifer Boldt and Kale Harbick from USDA-ARS, Charlie Hall from Texas A&M, as well as environmental control experts from Argus, Priva, and Wadsworth. This well-rounded team will help you select and operate climate control equipment and sensors for ideal crop growth.

The course runs from October 16 to November 10, 2023. The cost is $US265 per participant, with a 20% discount if you register 5 or more. All course material is completely online and available at any time of the day, and includes pre-recorded videos, an interactive discussion board with PhD professors and industry experts, and quizzes. Two new modules are activated each week during the course, for a total of 8 learning modules. Instruction is at your own pace and time within the 4 weeks of the course, with a typical time commitment of about 6 hours per week. Our courses are highly rated by participants with over 80% completion, and your resume will be enhanced with a customized certificate of completion from UF. Click here to register (http://hort.ifas.ufl.edu/training/).

For more information, go to http://hort.ifas.ufl.edu/training/, or contact Greenhouse Training, Environmental Horticulture, University of Florida, USA, Email: greenhousetraining@ifas.ufl.edu. The course is supported by the American Floral Endowment and the USDA-ARS Floriculture and Nursery Research Initiative.

Indoor Ag Science Café is an outreach program of our project OptimIA, funded by USDA SCRI grant program. The café forums are designed to serve as precompetitive communication platform among scientists and indoor farming professionals. The Café presentations are available from our YouTube channel: https://www.youtube.com/playlist?list=PLjwIeYlKrzH_uppaf2SwMIg4JyGb7LRXC   

Contact Chieri Kubota at the Ohio State University (Kubota.10@osu.edu) to be a Café member to participate. 

Please Submit Your Questions!
‘Indoor Ag Science Queries’

Please submit your questions (anonymously if you wish) about sciences and technologies of indoor farming to this submission site.  Any questions are welcome! You can submit them anonymously if you wish. The site is always open for your questions. Selected questions will be discussed in our first Indoor Ag Science Queries scheduled on December 3rd.

Indoor Ag Science Café in April was full of data on climate uniformity, crop productivity as well as energy use in indoor farming, presented by Dr. Murat Kacira.  Murat is a professor and the Director of Controlled Environment Agriculture Center at the University of Arizona. The first part was about the importance of designing air distribution system. Good air circulation is important for achieving temperature uniformity within the production system as well as minimizing plant environmental disorder such as tip-burn.  Murat’s research team works on optimization of the air distribution design by using a computational engineering approach called CFD – Computational Fluid Dynamics, which can visualize the possible difference in air speed and temperature distribution with different designs. Murat then described a theoretical analysis of energy use of indoor farms located in selected geographical locations (Duluth, Phoenix, Seattle, and Miami). Then he shared a recent study on lettuce productivity and tip-burn incidence under different combinations of CO₂ concentration and light intensity (daily light integral) conducted in his research facility at the University of Arizona. According to Murat, CO₂ enrichment increased tip-burn incidence at higher DLI. Therefore, 850 ppm CO₂ and 11-13 DLI is what he recommends and can achieve the energy use efficiency of 0.062 kg lettuce fresh weight produced per 1 kWh electric power consumption.

Press Release – Manitowoc, WI – Dramm is pleased to announce that they are partnering with Vifra, the specialists in humidity management, to offer their solutions to North American customers. Vifra focuses on helping growers optimize their greenhouse humidity. Founded in 1994 by Vincenzo Russo in Rome, Italy, Vifra produces high quality systems designed for easy maintenance and long life. Dramm is pleased to offer Vifra’s high-pressure fog and dehumidification systems to North American growers to help them optimize their growing climates. Vifra’s systems work to increase or decrease humidity as conditions demand. Often, these systems can be used in coordination with each other to adjust humidity levels throughout the day, allowing for the right climate for any crop at any time of day. Vifra offers High Pressure Fog Systems that operate between 1,000 and 1,800 psi, depending on the existing humidity and crop needs. These high-quality systems utilize specialized nozzles and stainless-steel construction. Specially designed fittings and connections prevent the need for guide wires make installation easy. Vifra systems use custom pumps, running at lower speeds, to reduce wear and ease maintenance. Vifra Dehumidification Systems utilize a decentralized approach to removing excess moisture from the greenhouse atmosphere. Dehumidification systems can aide in transpiration and reduce energy usage caused by reheating the greenhouse air during cold weather venting. By positioning the dehumidification units throughout the greenhouse, a more uniform result is achieved.

Dramm is pleased to work with Vifra to help North American growers manage their humidity. For more information, visit www.dramm.com or contact us at 800-258-0848. The Dramm Corporation has produced quality products and solutions for growers for over 75 years. Founded in 1941 with the invention of the 400AL Waterbreaker, the Dramm Corporation continues to innovate to help its customers flourish. Dramm manufactures over 35 different sprayers for indoor agriculture, offering a wide variety of choices for every spraying need.

The data platform for horti- and agriculture

30MHz provides agribusinesses with everything they need to start monitoring their crops and growing environment accurately and in real-time, with just minutes of setup. Customers choose from a variety of sensors sourced and developed with growers and agricultural research institutions (capturing metrics including VPD, dew point, temperature, humidity, soil moisture and airflow.) 30MHz also provides a private, scalable mesh network (with the option to easily add more sensors at any time) and an intuitive analytics platform with real-time alerts, visualizations, heatmaps, charts and graphs accessible on any device.  

With 30MHz technology, customers can deploy a wireless sensor network themselves, without technical expertise. Sensors arrive preconfigured— customers simply connect their gateway to a power supply and ethernet, and log into the platform to immediately start measuring.

Built to help agribusinesses of all sizes harness the full power of their environmental data, the 30MHz platform makes crop metrics accessible, shareable and actionable without the burden of juggling multiple interfaces. Real-time sensor data can be viewed alongside data from other sources, including climate control systems, shelf quality control and traceability monitoring and root zone monitoring software.

Empowering agribusinesses across the chain

The scalable and modular nature of 30MHz tech makes it a fit for growers of all sizes across agricultural verticals. With over 150 customers across five continents, 30MHz serves agribusinesses from farm to fork, in greenhouse, vertical (hydroponic and aeroponic), arable, ornamental, cold store, processing, packing, transport, retail and livestock. Based in Bedford, Texas, Hort Americas partners with leading suppliers of commercial horticultural products from around to world in order to serve the North American professional greenhouse and indoor ag grower community with the latest technologically advanced products from around the world. Hort Americas’ breadth of expertise across horticulture makes the company ideally positioned to bring the Dutch-founded 30MHz further into the North American market. “We’ve seen the hunger for actionable data among North American growers— they’re constantly looking to innovate and make the most of their resources. But they don’t have time for overly complex systems that silo their data and take forever to get off the ground. Hort Americas understand the specific challenges and needs of North American agriculture, and how to translate Dutch agri-innovation into efficiency and productivity in local contexts” notes Director of Customer Affairs Cor Jan Holwerda. “Hort Americas continues to look for cutting edge technology that solves problems and provides answers to the questions our grower partners are asking us.  With believe that 30MHz’s product portfolio does just that,” adds founder and general manager Chris Higgins.

More About 30MHz

30MHz helps agribusinesses of all sizes make the most of their resources with real-time data on their crops and environment, from farm to fork. Through an accessible data platform, scalable mesh network and a selection of wireless sensors, 30MHz provides all the elements growers need to start monitoring in moments, without technical expertise. All it takes is a few minutes and an internet connection.

More About Hort Americas

Based in Bedford, Texas, Hort Americas partners with leading suppliers of commercial horticultural products from around the world in order to serve the North American professional greenhouse and indoor ag grower community with the latest technologically advanced products. Learn more at www.hortamericas.com.

Milwaukee, WI, USA – Desert Aire, a Milwaukee-based manufacturer of commercial and industrial humidity and climate control systems, has published a new technical resource that explains how carefully defining grow room Vapor Pressure Deficits can produce maximum yields and have favorable impacts on the capital and operational costs of HVAC systems.

“Application Note 28 – Vapor Pressure Deficit and HVAC System Design” is a 6-page publication that helps growers, consulting-specifying engineers and mechanical contractors understand the impact of Vapor Pressure Deficit (VPD) on plant growth processes, protecting crops and maximizing yields.

Vapor Pressure Deficit is a metric that indicates the evapotranspiration potential of grow rooms based on current temperatures and humidity levels. The expressed value is the deficit or differential between the pressure exerted by the moisture at a specific room condition and the pressure at the surfaces of plant leaves.

Using explanatory text as well as color figures, charts and tables, Application Note 28 provides readers with a thorough briefing on the control of indoor grow environments through the management of VPDs. Understanding the fundamental impact of VPDs and temperatures on growth and yield is an important starting point for the planning of indoor grow facilities. The Application Note also outlines how strategically selecting grow room VPDs favorably impacts the sizing of environmental control equipment and associated costs.

Application Note 28 is the latest in a series of technical resources from Desert Aire intended to inform growers, consulting-specifying engineers and mechanical contractors about grow room issues and HVAC equipment strategies. Previous documents in the series included: Application Note 27 – HVAC-Systems and Grow-Room Energy Usage; Application Note 26 – Grow Room Environmental Control; and Application Note 25 – Grow Room Load Determination.

The publication “Application Note 28 – Vapor Pressure Deficit and HVAC System Design” is available for download as a PDF document at desert-aire.com. To receive a printed copy of the publication, email sales@desert-aire.com.

Desert Aire is a Milwaukee-based manufacturer of commercial and industrial dehumidification systems, environmental control systems and dedicated outdoor air systems. Desert Aire systems provide healthy and comfortable indoor environments while saving energy in a variety of settings including grow rooms; commercial greenhouses; indoor pool facilities; indoor water parks; ice rinks; schools and universities; rec and fitness centers; office and retail buildings; and water treatment plants. Desert Aire is a subsidiary of Multistack, LLC. Desert Aire’s main office is located at N120 W18485 Freistadt Road, Germantown, WI, 53022, USA. Telephone (262) 946-7400; Fax: (262) 946-7401; Internet: Desert-Aire.com.

Trying to produce vegetables in hot, humid conditions can be difficult for controlled environment growers whether growing in a greenhouse or a warehouse.

“The challenges of greenhouse growing in Ohio and the Midwest are different than the challenges faced by growers in Arizona,” said Ohio State University horticulture professor Chieri Kubota. Kubota, who joined the faculty at Ohio State this past June will continue the controlled environment agriculture research she was doing while at the University of Arizona.

“Some people think I’m an expert at dealing with heat stress because I was doing my research in an Arizona greenhouse,” she said. “But in Arizona growers don’t really have to worry about the heat inside a greenhouse if they are using an evaporative cooling system to lower the temperature. In Arizona the outside temperature can be 110ºF, but the temperature in the greenhouse can be lowered to 75ºF-80ºF (25ºC-27ºC) as long as the air is dry enough and water is available. In Arizona the dryness can be a challenge, causing tip burn on sensitive crops such as lettuce and strawberry.

“I really didn’t have to deal with heat stress much in Arizona. But there are other parts of the country like the Midwest and East Coast that have to deal with hot, humid summer conditions and very cold winters. I would like to work on those issues and develop technologies, including climate control strategies that can mitigate the issues of growing crops year-round. In Ohio and the Midwest summer heat stress is a major issue for crops causing all kinds of physiological disorders including incomplete pollination and fruit ripening disorders. During the winter, heating and humidity can also be an issue. There is also an issue with low light levels so supplemental lighting is more important.”

Because of the limited optimum growing season in greenhouses in the Midwest, Kubota said using indoor productions systems makes more sense compared to Arizona.

“In this part of the country it is very difficult to maintain the optimum temperature range year round,” she said. “And because of the increased interest in vertical farming, I expect to put more effort in warehouse production systems, including the use of LED lighting.”

Improving vegetable grafting

Some of the projects Kubota started at the University of Arizona that she will continue to work on are vegetable grafting and hydroponic strawberry production. She is a member of a research team lead by North Carolina State University plant pathologist Frank Louws that is working on vegetable grafting.

“I am continuing my research on improving grafting methods and the handling of grafted plants so that they can be shipped long distances,” Kubota said. “I am also creating a simple tool for growers to schedule grafted plant production. Having the grafted plants ready at exactly the same size is always a challenge for growers. The research group is working to develop a simple plant growth model based on environmental conditions to predict how many days are needed to finish a grafted crop.”

Kubota said the grafting research team is looking at a variety of plants, including tomato, watermelon, cucumber, eggplant, pepper and muskmelon.

“Growers are commercially producing grafted tomato and watermelon plants, but there are many more crops that can use grafting technology to reduce loss from soil-borne diseases and to increase yields. My program is looking at all of these potential crops.”

Kubota said the grafting research also has application to greenhouse crops.

“The grafting technology was originally developed for soil-based production, but greenhouse vegetable growers discovered that even though they are doing soilless production, using grafted plants can increase crop yields,” she said. “In North America, greenhouse growers were the first group who started using grafting technology. The field growers are now more interested since they have fewer means to control disease. In terms of potential market, field production in the U.S. is much larger in terms of number of plants.

“Currently tomato accounts for the majority of grafted plants in greenhouses. Increased tomato yields have been the driver for greenhouse growers to use grafted plants. Some greenhouse growers have been trialing grafted cucumbers and some research has shown that grafted eggplants can increase yields.”

Improving strawberry production

Kubota who has been working on greenhouse strawberry production for nine years will continue working on this crop with an interest in the use of LEDs.

“Strawberry fruit production is not as productive as leafy greens or tomatoes in terms of dollars of return relative to the input of light,” she said. “I’m interested in studying the increase in yields relative to the increase in light. What is the dollar value of that increase of yield by adding for example, 1 mole of light? Unless there is an improvement in lighting technology, it may not make sense to grow strawberries under supplemental lighting.

“I would like to come up with a smart lighting system to reduce the lighting cost based on the understanding of strawberry physiology and how plants are grown in a greenhouse. I think we could reduce lighting energy use and costs quite a bit by doing that. Strawberries are physiologically unique in terms of light saturation and also in terms of the sink-and-source relationship of how much sugar can be translocated from the leaves so that the photosynthetic rate can be maximized.”

Developing new crops

Another area that Kubota would like to expand for CEA production is the development of new crops.

“Controlled environment growers whether they are growing in greenhouses or warehouses need to diversify and increase the number of crops they are producing,” she said. “Although I don’t have any new crop projects coming up, I am particularly interested in small fruits. Since Ohio and the Midwest have a cold climate, there may be an opportunity to do more with small fruit crops like raspberries, blueberries, blackberries and other berry crops for greenhouse production.”

Kubota is also interested in revisiting the study of spinach production in greenhouse and warehouses.

“Controlled environment growers seem to have a particularly difficult time managing diseases including Pythium on spinach,” she said. “I am interested in determining if there is a practical way to manage these diseases. Cornell University researchers had previously done a lot of studies on this issue years ago. I wanted to see what the difference was between the successful hydroponic growing of spinach in Asia and other countries and why U.S. growers can’t do that too.”

Expanding professional training, research programs

As part of her extension efforts at Ohio State, Kubota wants to expand the opportunities for growers to receive professional training.

“I want this training to go beyond Ohio and to go nationwide and even international,” she said. “I’m interested in training professionals with online courses and other programs at a reasonable cost.

“The heart of the horticulture industry is in this part of the country. There are many different types of growers, supporting vendors and technology providers here. They are well connected.”

Kubota said at the University of Arizona research in the plant science department was focused more on basic science such as how a particular gene functions in plants, but not necessarily horticultural plants.

“Here at Ohio State I am in the horticulture and crop science department so the other faculty members understand what horticulture is,” she said. “There are a number of people here working on controlled environment agriculture including horticulture, which covers floriculture, hydroponics and high tunnels, and ag engineering, entomology, plant pathology and food safety. There is a complete set of researchers and extension specialists who can work on a variety of controlled environment agriculture issues related to horticulture crops. This makes it advantageous for not only developing research projects together, but also professional training for commercial growers.”

For more: Chieri Kubota, The Ohio State University, Department of Horticulture and Crop Science, kubota.10@osu.edu; http://u.osu.edu/cepptlab; https://hcs.osu.edu/our-people/dr-chieri-kubota; https://www.facebook.com/CEPPTLAB.

This article is property of Urban Ag News and was written by David Kuack, a freelance writer from Fort Worth, TX.

Lucayan Tropical Produce has been growing greenhouse vegetables in The Bahamas for 12 years, but it has taken some adjustments to find the best crops to grow on an island in paradise.

Since Lucayan Tropical Produce Ltd. began producing greenhouse vegetables in 2004, the company has experienced three major hurricanes, including Hurricane Matthew, this past October. Matthew, which was designated a Category 5 hurricane, had sustained winds as high as 160 mph. The company, which is located on New Providence Island in The Bahamas, operates a 5.5-acre Dalsem glass greenhouse producing cucumbers, lettuce and leafy greens.

While residents and tourists may consider the island to be “paradise,” the climate, cost of electricity and availability of fresh water can make for challenging growing conditions.

“Unlike traditional greenhouse operations we began the company with a concept that included many different types of crops in the same greenhouse,” said company president Cameron Symonette. “We felt that what we gave up on efficiency we would gain back on price. Being on an island, the prices of highly perishable items are generally quite high. We started with five different tomato varieties and three different colored bell peppers in the initial phase of the operation. We had two separate irrigation systems across six irrigation zones. That set up failed to work for us for a number of reasons; mostly because of the inherent difficulty of managing so many different types of crops from both a production perspective and from a packaging logistics/distribution perspective.

“The peppers weren’t a problem, but for the tomatoes, having different varieties with different requirements meant having to change the irrigation strategies. That was a challenge in our environment with the amount of solar radiation and the temperatures. The monthly average differences between day and night temperatures on a daily basis are not really significant for over 50 percent of the year causing challenges with fruit set and germination. That is the number one reason why we changed our approach. Currently we are producing only cucumbers in the greenhouse.”

Best crops for the climate, greenhouse design

While Lucayan Tropical Produce’s core crop is cucumbers, the company is also producing lettuces and leafy greens.

“We chose to focus on cucumbers for two reasons,” said Symonette. “One, because in our environment we are unable to achieve the yield per square meter that is required for tomato production to be commercially viable. In our environment of a high relative humidity and plenty of sunlight, cucumbers grow well. It was just a better crop for us to grow.

“The second reason is the time between when we plant and harvest the cucumbers is much quicker than it is with tomatoes. Any issues that we might have related to a crop failure or if we need to replace old plants, the time to do that is much faster with cucumbers.”

Lucayan Tropical Produce is also producing a variety of lettuces, leafy greens and herbs that it sells domestically.

“Summer temperatures definitely limit the leafy greens we can grow,” Symonette said. “We find the most success growing leafy greens from the beginning of October until the end of May. We currently grow on ebb-and-flow tables, which were originally designed as a propagation area for the crops in the main greenhouse. We didn’t have the luxury of being able to buy our starter seedlings from another local grower so we built the propagation area so we could do it ourselves. Over the last two years we have been running trials with a NFT and a pond system to determine what is the best system for trying to extend our growing season into the summer months.”

Symonette said the company is also interested in building a controlled environment facility to produce lettuces and leafy greens.

“We want to expand our lettuce and leafy greens production during the first quarter of 2017,” he said. “That expansion will take the form of a temperature controlled system with artificial lights. It doesn’t mean vertical growing, but it does mean growing under lights. That system would be built inside our packing area.”

The company distributes its cucumbers, lettuces and leafy greens through two wholesalers.

“Our intention is to sell as much of our product domestically as we can before we export,” Symonette said. “The lettuce and leafy greens are only sold domestically through Bahamas Food Services. Since we’ve started to export the cucumbers, we have been working with Sun Produce in Florida that distributes our product in the United States and Caribbean.

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“The market acceptance of our products has been phenomenal. The taste and shelf life are great. We’re focused on supplementing what we grow in the greenhouses with some growing under lights to add product mixes that we couldn’t grow in our environment that would sell well in our market.”

Making improvements

The greenhouse was initially designed with two 250,000-gallon rain water holding tanks so water that falls on the greenhouse roof is collected and used for irrigation.

“Because of the monthly rainfall patterns, we also have a reverse osmosis system installed in the greenhouse that we only use during a six-week window during the year,” Symonette said. “We do not have access to fresh water, which is a problem with agriculture in general in the country. High property prices and no access to water limit potential growing operations.”

The company has made significant improvements to its irrigation systems over the last 10 years.

“We recently upgraded our water purification system to a combination of ozone and UV filtration which is really working,” Symonette said. “It leads to higher oxygen levels, which in turn leads to better root health.

“The second improvement is in employee training, which is a critical component. Because we have been in business for over 10 years, we have team members who are more experienced and have learned the systems we have developed, which has led to a more efficient operation than when we started.”

Symonette said the company looked extensively at improving climate management with its current greenhouse but determined it was not possible to improve the climate because the cost of electricity is cost prohibitive.

“Any technological solution in an open environment would not increase yields enough to justify the increased costs of electricity,” he said. “The greatest potential opportunity is in an energy-efficient closed growing system for producing leafy greens under lights where the temperature and humidity can be controlled.

“We also have a trial solar panel installation at our facility and are seriously considering expanding that to a size that would run the daytime requirements of the operation.”

Future expansion considerations

Symonette said the biggest issue to maintaining the proper greenhouse climate is the similarity between night and day temperatures.

“That would be the predominant factor, which basically influences what we are able to grow,” he said. “Looking back the greenhouse design focused on protecting the structure from hurricane damage, but ultimately negatively impacted airflow. As we expand greenhouse production we will think about using our growing experience to make some decisions. With the benefit of hindsight and experience, we will make some different choices that will generate greater airflow.”

Symonette said every time the company has experienced a major weather event, such as a hurricane, changes have been made in operations.

“We think about what happened and why it happened and put some thought into how we can prepare in a more sensible way,” he said. “Each storm has brought different learning experiences, but none of those major hurricanes or other weather events has caused us to change the construction.”

Symonette said the company will look at expanding its greenhouse growing area next year.

“We’re not sure what form that will take,” he said. “There are no government restrictions on making that expansion. The government is very supportive of us and encourages agricultural participation.”

For more: Lucayan Tropical Produce,
(242) 377-0125; info@ lucayantropical.com.

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

Although it may be difficult to create the perfect greenhouse climate for growing plants, there are variables growers can control to maximize plant growth.

Regardless of the type of crop being grown in a greenhouse, the climate a grower is trying to achieve requires controlling the same variables.

“Greenhouse growers are trying to control temperature, humidity, light level, carbon dioxide, and in some instances, airflow and air distribution,” said mechanical and agricultural engineer Dr. Nadia Sabeh, founder of Dr. Greenhouse. “Depending on the crop, these variables have different set points. They also might have different acceptable maximum and minimum ranges or levels.

“Depending on the crop, these variables can be changed during different times of the day. For instance, a tomato crop wants a daily average temperature around 72ºF. If the plants experience high temperatures during the day, if the temperature is able to be cooled down during the night, as long as the average temperature is 72ºF, the tomato plants are happy. For lettuce, a grower may not be able to manipulate the day or night temperature to make up for exceeding the maximum temperature that occurs during the day or night. That’s one way these crops differ.”

Sabeh said when it comes to controlling the greenhouse environment growers usually focus first on temperature.

“The first line of defense against warm temperatures is not shading,” she said. “Growers are trying to maximize as much light into the greenhouse as possible. As soon as a shade curtain is closed the solar input is reduced. The first line of defense for cooling a greenhouse is ventilation, either natural or mechanical.

“If ventilation can’t achieve the temperature a growers needs, then some form of cooling is added. Typically cooling is done through evaporative cooling. This could be wet pads and a fan system, high pressure fog or a low pressure misting system in combination with mechanical and natural ventilation. If that doesn’t work, then a shade curtain can be pulled. A shade curtain is usually only drawn for two to four hours during the day. It’s pulled during the peak solar heat gain period. A shade curtain can cut the temperature by 2ºF-4ºF.”

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The challenge of reducing humidity

Sabeh said between controlling the greenhouse temperature and humidity, humidity is the more challenging variable, especially if it is for dehumidification.

“If a grower is trying to remove moisture from the greenhouse, that presents a lot of challenges,” she said. “The standard method of removing moisture from the greenhouse is through ventilation. But that assumes that the moisture level or the humidity outside the greenhouse is lower than it is inside the greenhouse.

“If a grower is looking to increase the humidity or humidification, for a greenhouse located in the southwest U.S. where it is very dry, moisture can be added to the greenhouse using evaporative cooling. Another benefit of evaporative cooling is a reduction in the temperature that cools the greenhouse temperature. Evaporative cooling works very well in a dry climate to do both of those things.”

Sabeh said growers in the Midwest and Southeast can experience more challenging climates because they have a high heat solar gain like growers in the Southwest experience, but they also have high humidity levels requiring them to ventilate.

“The climates in the Midwest and Southeast make it very challenging to grow plants in a greenhouse because of the humidity,” Sabeh said. “The only line of defense for growing plants in that kind of climate is ventilation. Growers want to exchange as much air as possible with the outside to remove moisture and solar heat gain during the day. Typically that is inadequate. If the outside temperature is 90ºF and the relative humidity is 90 percent, growers certainly don’t want those conditions in their greenhouses.

“If the temperature and humidity are high, growers don’t have the opportunity to use evaporative cooling because they can’t reduce the temperature enough,” she said. “They can shade the greenhouses, but that only lowers the temperature by 2ºF-4ºF from outside conditions. If it is 90ºF and 90 percent humidity, pulling shade results in 86ºF and 90 percent humidity, and that is not going to provide the vapor pressure deficit a grower is trying to achieve.”

Sabeh said growers might consider closing up their greenhouses to avoid bringing in hot, moist air, but that creates additional challenges.

“Closing the greenhouse can cause the greenhouse to heat up from the sun plus the plants are releasing moisture resulting in the greenhouse just getting hotter,” she said. “So far I haven’t really seen anyone come up with a very cost effective method to mitigate that heat and moisture. Certainly a grower could use a refrigerant-based cooling system similar to an air conditioning system that would provide dehumidification. But the size and scale of those systems are cost prohibitive.”

Maintaining the proper vapor pressure deficit

Sabeh said temperature and humidity are very closely linked through the vapor pressure deficit (VPD).

“As long as a grower is able to control the greenhouse temperature, that usually means he is able to control the humidity level to the point where the vapor pressure deficit is where it should be,” she said. “Even if VPD is not the target that a grower is going for, that is actually the target that he is trying to reach with temperature control with or without humidity control.”

VPD is the difference between the amount of moisture in the air and how much moisture the air can hold when it is saturated.

“There is an optimum level for VPD,” Sabeh said. “For leafy greens and culinary herbs, which prefer a lower VPD, the accepted VPD range is 0.65 to 0.9 kilopascal (kPa) with 0.85 kPA being optimum. Tomatoes, cucumbers and peppers tend to like it drier. The VPD range for tomatoes is 0.9 to 1.2 kPa.

“For leafy greens there is more surface area for moisture to escape the plants. The plants like to be in a more humid space so they don’t release too much moisture too fast.”

Providing adequate airflow

Sabeh said airflow in the greenhouse is really important for breaking up the layer of moisture around the leaf surface of the plants.

“If the leaves are transpiring water, the leaf surface itself is considered saturated,” she said. “The leaf surface is exchanging moisture with the air around it. The more moisture in the air around the leaf surface, the less tendency to transfer moisture from the leaf surface to the air around it.

“This is basically what the vapor pressure deficit is. It is the difference between how much moisture there is at the leaf surface at a given temperature vs. how much moisture there is in the air at that same temperature. If it is within the right range, then the plants are happy because the leaves are freely exchanging moisture with the air. If the vapor pressure deficit is too low that means the air has a lot of moisture in it so there is going to be less transfer of moisture from the leaves to the air. The plants can’t transpire as quickly and nutrients can’t be delivered as quickly to the rest of the plant. If the vapor pressure deficit is too high, the air is really dry, and the plants shut down. As a protection strategy, the plants will close their stomata so that they don’t transpire moisture to the air because it would occur too fast. The loss of water through transpiration would occur faster than the plants could take up water.”

Sabeh said horizontal airflow fans are the traditional method for producing airflow and air currents in a greenhouse.

“Horizontal airflow fans are usually suspended from the trusses or the structure of the greenhouse and blow air in a circular pattern over the tops of the plants without actually blowing directly down on the plants,” she said. “Just the circulation and motion is enough to create turbulence to cause air mixing around the plants to encourage transpiration and convection.

“By breaking up the little saturation pocket of air around the leaves, it facilitates that moisture transfer from the leaves to the air. Under more humid conditions, as air is blown over the leaf surface, a grower can facilitate more transpiration from the plants than if no airflow was blowing over it. Airflow is one of those variables not addressed as often as temperature and humidity control. It is sorted of neglected.”

With the increasing interest in vertical farms, Sabeh said growers are using large grow racks to try to create temperature and humidity conditions in three dimensions.

“Under these conditions it is very easy for air to get trapped over the center of a rack,” she said. “Vertical farmers are really cognitive of airflow because they see these hot spots or these wet spots in the middle of the grow racks so they know they need airflow.

“It is the same situation as if plants are grown in a greenhouse. If more airflow is provided in a greenhouse, more moisture could be removed from the plant surface and help the plant with cooling by convection.”

Maintaining the proper carbon dioxide level

Sabeh said although carbon dioxide is not necessarily impacted by the outdoor climate, greenhouse growers are controlling it relative to the outdoors.

“In a greenhouse where growers are burning fuel to generate carbon dioxide and ventilating at the same time there is a challenge of how much carbon dioxide should be delivered and how is it going to be retained? Is there a way to mitigate the carbon dioxide’s immediate loss to the outside air through greenhouse ventilation?

“One strategy for not overusing carbon dioxide is to provide plants with a boost from carbon dioxide enrichment. Carbon dioxide can be provided first thing in the morning during first light before the greenhouse vents are open. Basically the plants take a deep breath when the sun starts to come out and the stomata open. The sunlight or the supplemental lights are turned on and the plants take up that carbon dioxide. When a grower starts to ventilate because the moisture has built up overnight or the temperature starts to increase because the sun is rising, enrichment with carbon dioxide can be stopped so that it is not being blown out of the greenhouse through the vents and exhausted by the fans. Some growers use carbon dioxide enrichment all day as long as there is enough light from the sun or from artificial light.”

Sabeh said growers can mitigate the loss of carbon dioxide by trying to deliver it as close to the leaves as possible.

“Some growers use under-floor or under-bench ducts to deliver carbon dioxide,” she said. “Some growers may use PVC tubing or fish tubing to distribute carbon dioxide through the crop and directly to the leaves. This is ideal if a grower can find a way to deliver the carbon dioxide in an effective manner without getting in the way of all of the other equipment and people working in the greenhouse.

“This is why some people are looking at the potential advantage of growing in vertical farms. There is an enclosed space and in most cases it is being done in buildings that are not leaky. There are some growers who have considered closed greenhouses. The cannabis industry is really interested in this, but the problem is there is an outrageous energy bill to try and close the greenhouse and not use any ventilation or mechanical cooling.”

Relationship between greenhouse climate variables

Sabeh said the optimum level of carbon dioxide varies for each crop. She said 700-1,500 parts per million carbon dioxide is the level that most growers are trying to use.

“Carbon dioxide is most useful to the plants when there is a lot of light and good temperature and humidity levels or a good VPD,” she said. “Carbon dioxide is transferred through the leaf stomata, the same as moisture through transpiration. At the right VPD the stomata are open to the maximum and are letting out moisture and gulping up carbon dioxide.

“The first thing is having the right VPD to maximize stomata opening. The second thing is photosynthesis, which is driven by light. If the air is being enriched with carbon dioxide, but the light level is very low, much of the carbon dioxide will be wasted. There has to be enough light to facilitate a high enough rate of photosynthesis or the plants can’t use the carbon dioxide. All three of these variables work together. A good VPD is needed for stomata opening. An adequate light level is needed for photosynthesis. And carbon dioxide is needed to maximize the photosynthesis cycle.”

For more: Nadia Sabeh, (916) 775-3724; nadia@doctorgreenhouse.com,
http://www.doctorgreenhouse.com.

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

Proper HVAC Maintenance Delivers Savings and Reliability

By John Zimmerman

Learn what preventive maintenance should be done on a controlled environment agriculture heating, ventilation and air conditioning system and what it can cost you if it’s not.

In Urban Ag News Issue 11, I introduced Jeffrey Orkin, CEO at Greener Roots Farm, a hydroponic controlled environment agriculture operation in Nashville, Tenn. I was monitoring the power consumption of Greener Roots Farm’s heating, ventilation and air conditioning (HVAC) system as part of a case study, when one of the compressors in the system failed. Because I had a power monitor on the system before and after the compressor was replaced, I was able to determine how much energy and money the HVAC system was wasting as a result of the problems that led to the compressor failure.

Preventive maintenance schedule

Before I present data on why Greener Roots Farm’s compressor failed, I’m going to discuss a basic HVAC preventive maintenance (PM) schedule. I’ll also highlight the importance of each maintenance activity and provide variations to the schedule that make sense for indoor growing applications.

HVAC preventive maintenance basics

Three common factors that determine the makeup of an effective PM schedule are:

1. The type of HVAC system.

2. The application the system is serving.

3. The ambient conditions within which the system operates.

These factors determine the type of activities that are required as part of the PM schedule and the frequency with which they need to be performed.

The type of HVAC system used determines the components that require PM. For example, a chilled water system requires a relatively elaborate PM schedule because of the number of complex components in this system. Greener Roots Farm has a direct-expansion (DX) split-system, much like those used in residential applications.

Chilled water system components DX split-system components

Chiller(s) Air handler

Pump(s) Condenser

Cooling tower(s)

Air handler(s)

Based on the number of components that require PM, a DX split-system has a much less complex PM schedule than a chilled water system. However, the PM schedule for Greener Roots Farm’s DX split-system differs greatly from a residential application, primarily due to the difference in operation.

The HVAC system for an indoor growing operation needs to operate 24 hours a day and treats a very high latent load (very moist air). Compare that to a residential HVAC system that cycles on and off based on the relative comfort of the space and treats a much lower latent load, thereby reducing wear and tear on the components. Additionally, the high moisture content of the air in indoor growing operations opens the door for issues that residential systems rarely encounter. These include corrosion of metal parts including linkages and drain pans, clogged condensate lines and mold.

The ambient conditions in which a system operates can greatly impact the wear and tear of the system’s components. Greener Roots Farm’s case highlights this fact. The term ambient conditions refer to the immediate surroundings of the system or components of the system. For the purpose of this article, the focus is on the impact ambient conditions have on outdoor components. However, as described above, moist air indoors can negatively impact indoor components as well.

For most systems, components located outdoors are designed to reject the indoor heat to the outside air. In a DX split-system, like at Greener Roots Farm, the outdoor (and heat-rejecting) component is the condenser. In order to reject the heat, the condenser uses a fan to force air across the coil, allowing the heat from the refrigerant inside the coil to be transferred to the cooler outside air (See Figure 1).

When creating a PM schedule for a condenser, the surrounding dirt, dust and debris that can reduce the component’s ability to properly reject the heat must be taken into consideration.

Figure 2 shows how dirt, dust and debris can impact a condenser. Ambient conditions including annual rainfall, direct sunlight and wind have an impact on the life of outdoor components and must be considered when creating a PM schedule.

Sample PM schedule for a DX split-system

Greener Roots Farm case study

There were two reasons that the compressor failed at Greener Roots Farm, both of which are directly related to the system’s ability to reject heat.

1. The outdoor condenser coil was extremely dirty. A dirty condenser coil reduces the airflow across the coil, subsequently reducing the amount of heat that the forced air can remove.

2. The indoor air handler had a loose belt. A loose belt reduces the airflow to the indoor growing space, causing the overall heat content of the return air to rise.

To further complicate things, the condenser at Greener Roots Farm had a two-row coil. This means that even if the perimeter coil (the visible coil) was clean, there is still a possibility that the interior coil was dirty. This is what happened with the Greener Roots Farm condenser (See Figures 3 and 4). The perimeter coil is clean, but the interior coil had not been cleaned for a long time.

Greener Roots Farm was paying a local contractor to do PM on its HVAC system twice a year.

While the sample PM schedule above suggests PM should be done on an HVAC system in an indoor growing setting on a quarterly basis, the coil on the Greener Roots Farm condenser should not have gotten this dirty. Although the hired contractor may have cleaned the perimeter (visible) coil twice a year, it was obvious that that the interior coil had not been cleaned.

Some costs that result from poor PM on an HVAC system are easy to quantify, including the cost of a new compressor, the money wasted for a PM contractor and the downtime associated with fixing the problem. However, the increase in energy cost over time as a result of a slow degrading system is very hard to quantify. Luckily for Greener Roots Farm, a power monitor was placed on the system for three days (spanning four calendar days) before the compressor failed.

We continued to monitor the power for 27 days after the compressor was replaced, the coil was cleaned and the belt was replaced The power monitor took readings in 10 minute intervals.

Below is a summary of the results.

Total power (kW) used

Before: 2,498  |   After: 1,857  |  Delta: (641)

Total energy cost ($0.11)

Before: $274.78  |  After: $204.27  |  Delta: ($70.51)

Cost per day

Delta: ($23.50)

Greener Roots Farm power monitor data

Before presenting Greener Roots Farm power monitor information, there a few disclaimers about the data.

1. In a deliberate, controlled experiment, three days would not be an adequate time sample, especially to determine the increase in degradation over time. However, three days was the amount of time available.

2. Since the power was being monitored for the last three days before the compressor failed, it can be assumed that these were the most inefficient days and that every day before this three day period would have been incrementally more efficient.

3. Furthermore, the assumption was made that this indoor growing facility was operated the same for both time samples.

4. In order to make an accurate comparison, a four calendar-day sample of the post repair time period was chosen that had approximately the same outside air conditions.

Here is a summary of those conditions:

Temperature comparison (Fahrenheit)

Looking at the outside air temperature comparison, temperatures during the time sample after repairs were made were slightly higher, but the power usage was still less.

Lessons learned

The Greener Roots Farm HVAC case study is not a complex, scientific experiment. However, it is a simple example of how poor preventive maintenance can cost growers money in the long run. This case study should also serve as a reminder to ensure that contractors are performing the work they were hired to do.

Many of the preventive maintenance activities for HVAC systems, including cleaning coils, can be done by most employees with materials available at local hardware stores. I recommend growers do some of these activities. This will allow them to become familiar with the results should a professional HVAC technician be hired to do the maintenance.

About Harvest Air

harvestairllc.com

Harvest Air was founded by Chris Whaley and John Zimmerman in July 2015. Both Chris and John are registered professional engineers with a combined 30+ years of experience designing, estimating and managing the installation of large-scale commercial heating, ventilating and air conditioning (HVAC) systems for a wide range of industries.

Controlled environment agriculture (CEA) requires a sophisticated farming process to ensure that crops receive the proper amount of water and nutrients in order to optimize yield. While it might appear that the farming techniques used in CEA are well designed and sophisticated, Chris and John discovered that many of the HVAC systems used in CEA are not adequate. By applying proven principles and knowledge gained from their experience, Harvest Air’s HVAC solutions are extremely efficient and reliable, allowing farmers to focus on their crops and not the infrastructure that supports them.

John Zimmerman, PE
Co-Founder and President
john.zimmerman@harvestairllc.com

John Zimmerman obtained a bachelor’s degree in mechanical engineering from the University of Texas-Austin and a master’s degree in building construction management from Purdue University. He is a registered professional engineer in Texas.

Chris Whaley, PE
Co-Founder and CEO
chris.whaley@harvestairllc.com

Chris Whaley obtained a bachelor’s degree in mechanical engineering from the University of Oklahoma and is a registered professional engineer in Texas.

Both John and Chris have spent their careers designing, selling and managing the installation of mechanical systems for large-scale commercial buildings for some of the largest mechanical design-build companies in the United States.

More predictable production levels and harvest dates are driving growers to adopt controlled environment agriculture.

Even though most greenhouse vegetable growers are producing fewer types of crops than ornamental plant growers, trying to control the environment of these food crops can be a much bigger challenge.

“The environmental control challenges for vegetables are much tougher because the produce is going to be consumed,” said University of Guelph professor Mike Dixon, who is director of the Controlled Environment Systems Research Facility in Guelph, Ontario, Canada. “The fact that they are destined to be a food commodity requires more attention to things like pest control.

“For vegetable production, since the margins are typically small for food crops, growers are trying to tightly control inputs as much as they can without compromising the quality and productivity of the commodity. This is a significant challenge and requires a great amount of detail to environmental control than for typical ornamental crops. Ornamental commodities, since they are not eaten, are not subject to the same kinds of stringent controls, especially with pesticide residues. But it’s more than that. The food safety regulations for food crop inputs and production outputs (e.g. nutrient runoff) are much tighter than they are for ornamental commodities. That means that environment control is a key factor in maintaining production standards and quality standards in a competitive market.”

Meeting market expectations

Dixon said part of the issue with trying to maintain the proper environment for vegetable production is consumer expectations for “perfect” fruits and vegetables.

“Consumers have been conditioned by generations of what today are considered environmentally unacceptable cultural management practices, using chemicals and pest management protocols, that occasionally leave residues,” he said. “Consumers don’t want peppers with spots on them. Consumers don’t want roses with blemishes on the flower petals. In the minds of consumers, they expect virtual perfection and don’t appreciate that the means to achieve this are not necessarily environmentally correct today.

“There is a transition between the old ways of doing things and the new ways of doing things. In terms of controlled environment agriculture, growers are transitioning to production practices that don’t compromise quality and productivity and yet meet environmental standards as well. That can be a tough balance.”

Dixon said that growing food crops in the northern latitudes year-round requires some type of controlled environment production.

“In Canada, six months out of the year food crops can’t be produced unless they’re grown in a controlled environment,” he said. “This requires that the growing has to be done in a nearly subtropical environment in which many disease pathogens and insects thrive. These pests gravitate toward these ideal controlled environment conditions. It’s the growers’ challenge to maintain some kind of balance and still meet the quality and production requirements of the market.”

Minimizing costs, maximizing production

Dixon said the degree of sophistication that is achievable with today’s technology should really be taken advantage of by growers especially in regards to minimizing labor.

“Labor is the top line in the cost of production in a controlled environment commodity,” he said. “Automation, including computer controlled environments and automated irrigation can mitigate the labor bill. Energy is a close second in regards to major costs.”

Dixon said the winter environment in the northern areas of the United States and in Canada is a major challenge for controlled environment growers.

“Winter production in these areas requires a higher level of technical sophistication than is needed for operations located further south,” he said. “The farther south an operation is located the issue then becomes heat extremes. In the middle latitudes, which include a large portion of the United States, environment control challenges are not as extreme as they are in Canada, Mexico and South America.

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“In more moderate climates, growers tend to be slower in adopting more sophisticated technology because the cost benefit is harder to justify. Labor costs will be the major factor that will drive the conversion to automation for a lot of middle latitude growers. Up until recently they haven’t been required. What has changed is that the capital cost requirements for a lot of technology enhancements or retrofits in older greenhouses have become very attractive. For example, the cost of LED lighting is not only energy conservative, but it can also enhance productivity with the appropriate technology and application information.”

More predictable, profitable production

Dixon said since the margins on food crops are relatively small compared to many ornamental crops, growers need to have relatively large greenhouse operations in order to be profitable.

“We’re talking on the order of 50-200 acres of controlled environment greenhouses,” he said. “To consider manually managing that scope of a greenhouse production system is prohibitive. It’s not realistic, growers couldn’t do it. It’s absolutely required that that they engage some form of automation, controlling especially irrigation, lighting and conventional environment control including opening vents, etc. The largest controlled environment food production area in North America is in the Leamington area in southwest Ontario. This area is typified by very large, highly sophisticated controlled environment agriculture systems for the production of tomatoes, peppers and cucumbers.”

Dixon said automating irrigation to reduce labor costs and automating basic temperature and humidity control in the greenhouse will significantly enhance the production system.

“It comes down to the cost benefits analysis,” he said. “Each grower has to look at it on the basis of their own specific case. It depends on the commodity. It depends on the local market and the margins growers can obtain with a more homogenous quality that they realize with automation. Automation offers more predictable production levels and predictable harvest dates. These are the kinds of issues that drive the adaptation to controlled environment computer automation and even robotic systems.

“Adding more sophistication gives more reliability in some cases as well as predictability in terms of production and quality. And that can only enhance a grower’s attractiveness to the market.”

Dixon said automating irrigation to reduce labor costs and automating basic temperature and humidity control in the greenhouse has been shown to significantly enhance the production system of a grower’s greenhouse.

“That’s really the goal,” he said. “Look at the capital cost requirement to obtain that level of technical sophistication and amortize over a reasonable three- to five-year period. Then look realistically at the labor savings, energy savings and the environmental impact savings including waste and runoff that would be realized by doing it. If it makes economic sense then there’s the answer.

“Sometimes it’s difficult to line up all of the things that need to be considered in a cost-benefit analysis. Depending on the size of an operation, if it’s a small-scale operation, it may not make economic sense to incorporate this automation because the cost-benefit is probably going to take 10 years to realize. But as the scale of the operation goes up, generally the justification for automating the system and reducing labor costs is greater.”

Bringing space technology back to Earth

One of the major elements of Mike Dixon’s research program at the University of Guelph’s Controlled Environment Systems Research Facility is the development of technologies for food production (i.e. life support) in the context of long term human space exploration missions. Dixon said the technologies being transferred from his program to the greenhouse sector are those that were developed for these missions.

“These technologies are being adapted to terrestrial agri-food sector applications in as economical a way as possible,” Dixon said. “Some of the technologies being developed include LED systems, environment control protocols, recycling systems, environment sensors and imaging systems for diagnostics.Terrestrial agriculture is benefiting greatly from research activities taking on the challenge of growing food on the Moon and Mars.”

For more: Mike Dixon, University of Guelph, Ontario Agricultural College, School of Environmental Sciences, Controlled Environment Systems Research Facility, Guelph, Ontario, Canada N1G 2W1; (519) 824-4120, Ext. 52555; mdixon@uoguelph.ca; http://www.ces.uoguelph.ca.

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

Whether you’re growing in a greenhouse, warehouse, or container, climate management is key to the success of your operation. If you’re ready to improve your understanding of HVAC systems, how they impact crop health and productivity, and aren’t afraid to use a calculator, this hands-on workshop is for you!

Dr. Nadia Sabeh (aka. “Dr. Greenhouse”) is an Agricultural and Mechanical Engineer with nearly 20 years of experience designing climate management systems (HVAC) for indoor plant production facilities, including greenhouses, vertical farms, plant factories, container farms, cannabis grows, and mushroom houses.

Dr. Sabeh is a licensed Mechanical Engineer in Sacramento, CA.

Date: Friday, October 27, 2017

Time: 1:00-5:00pm

Where: Denver, CO @Blue Moon Brewing Company

Who: Dr. Greenhouse (Dr. Nadia Sabeh)

Register at www.doctorgreenhouse.com/workshops.html

Register now to save your seat!
​To keep this workshop interactive, they are limiting registration to 50 seats.

Topics covered:

1. Introduction to HVAC system types for both greenhouses and indoor farms

2. How to calculate basic heating, cooling, and humidity loads

3. Review of design criteria and constraints that are unique to each grow operation

4. Introduction to the Psychrometric chart and why it’s important

5. How to measure plant evapotranspiration rates to improve HVAC design

6. Being able to differentiate between the “good” and the “too-good-to-be-true”

7. Overview of basic terms and concepts in horticulture and engineering