Nick Chaney, the head grower at BrightFarms’ Chicagoland greenhouse, helped develop the hydroponic grower’s newest lettuce variety: Sunny Crunch. Chaney says that BrightFarms knew Sunny Crunch would be a success when it drew rave reviews from people who tried it during a greenhouse visit.

“Everyone who pulled one of those leaves out of the system and tried it, you could see their face just lighting up,” Chaney says. “When we started seeing that reaction from everyone who tried it, we knew it was going to have success on the shelves and we’d go forward with it.”

Below, Chaney answers questions about Sunny Crunch’s profile, BrightFarms’ development process and what crops are challenging to grow in a hydroponic system.

Produce Grower: What exactly is Sunny Crunch? And what was the inspiration for its development?

Nick Chaney: Sunny Crunch is a lettuce we began to develop in our system as an iceberg/green leaf hybrid. So, you get all the flavor and color of more nutritional lettuces, but it’s got that nice crunch that people like with the iceberg. The varieties we’re using for that were actually developed as head lettuces and we decided to try it out as a baby leaf. It has a much higher density and much shorter growth cycle and it came out performing very well.

PG: How does BrightFarms develop something like Sunny Crunch, and then bring it customers?

NC: It can develop from a couple of different avenues. We are in constant contact with our customers, [and] get feedback on what they want to see. As a team, we reach out to seed breeders and see what could be possible in hydroponics and order it all in. We run it through [our] system and see how it develops. If it works in hydroponics, and will be desirable to the consumer, we bring in sales, marketing, operations, our apprentice growers — everyone is involved — and go through stages of a crop’s feasibility in the greenhouse, its marketability and then take it from there. Something that is simple like a lettuce could get pushed through in two to three months, while something a little more complex [to grow] and isn’t ideal for hydroponics could take as long as six to seven months.

PG: What is an example of something that could take six to seven months to grow in hydroponics?

NC: I trialed mint. Mint had really struggled in hydroponics because it’s really slow growing and didn’t really have that strong flavor that it has in soil growing. But there’s an endless supply of genetics out there, so you just have to keep on pushing through and trialing and finding what works for both flavor and production.

This interview was edited for style and clarity.

Genetics: The cultivated strawberry (Fragaria × ananassa) is a domesticated crop resulting from hybridizing several wild strawberry species. The vast majority of cultivar development has been focused on varieties that are well-suited to field production in mineral soils. While there have been some efforts to develop cultivars specifically for controlled-environment production, this has taken place in other counties. For growers here in the U.S., they will need to trial cultivars to identify which are suitable for their geographic location, production environment and market.

Production systems: Strawberries are most commonly produced in systems using soilless substrate, and there are several systems suitable for production. There are some containers that are manufactured specifically for hydroponic strawberry production and may be suspended on pipes or rails, or placed on top of gutters (Fig. 1). Additionally, long, continuous troughs may be filled with substrate and used for strawberry production. In addition to these systems, which are designed specifically for strawberries, smaller-scale producers may utilize containers such as hanging baskets or one-gallon nursery containers. Regardless of which system you select, a growing substrate that is very free-draining should be used. Soilless substrates comprised of organic components like coconut coir and peat moss and inorganic components like perlite are most commonly used.

Propagation and young plant production: Strawberries can be propagated in several ways. Tissue cultured plantlets can be purchased and bulked up prior to transplanting. Runners can be taken off plants, planted into small containers or cell trays filled with substrate, and placed under mist to root. Once rooted, these plants are then grown until they are sufficient size. Plants can also be dug from fields and placed into storage at temperatures below freezing until transplanting. Growers will need to propagate their own plants for production or seek out reputable suppliers of young plants.

Nutrient solution: Strawberries should be irrigated with smaller volumes of water at a greater frequency to avoid water-logging the root zone. Nutrient solution electrical conductivity (EC) can be lower compared to other crops from around 1.0 to 1.5 mS/cm, and pH should be maintained between 5.5 and 6.0 to help manage substrate pH and micronutrient availability. Specifically, strawberry plants can be susceptible to iron deficiencies, and if cooler production temperatures are used, this can be exacerbated. Strawberries also require elevated levels of potassium for developing fruits and calcium for calyces.

Temperature: Day temperatures around 75° F and night temperatures around 60° F are commonly used. While strawberries grow well under cool temperatures, growing too cool can result in long crop times. Alternatively, excessively warm temperatures (>85° F) can damage plants and reduce productivity.

Light: Strawberries can be considered a high-light plant. Using supplemental light to increase light intensity in the late fall, winter, and early spring can improve yield and fruit quality. In addition to supplemental light to increase photosynthesis, low-intensity lighting can be used to alter the photoperiod (day length) or light quality. While June-bearing cultivars flower in response to short days and ever-bearing cultivars can flower under a range of day lengths, there are some cultivars that require or are most productive under long days and, as a result, lighting is required to promote flowering when the day length is too short. Some growers use low-intensity light rich in far-red light, as this can promote flower truss elongation and allow the fruits to hang down, out from the canopy.

CO₂: Supplemental carbon dioxide (CO₂) is useful for enhancing growth in the winter when ventilation is limited and CO₂ concentrations in the greenhouse can drop and limit plant growth. Supplemental CO₂ to maintain concentrations from 500 to 1,000 ppm can be provided by burners or liquid injection.

Pollination: Strawberry flowers may be self-pollinated. However, complete pollination is important for producing well-formed fruits. Strawberry flowers may be pollinated by hand using a vibrating wand; while this is useful for small plantings, the labor-intensive nature of hand pollination may not be practical or feasible for large operations. In outdoor production, strawberries are pollinated by wind, and this can be mimicked in the greenhouse. Hair driers on the “cool” setting or hand-held leaf blowers can be used to pollinate flowers, and this is less labor-intensive than hand-pollinating with a vibrating wand. Bumblebees can be used to pollinate strawberries and are most effective for large-scale plantings, as they require minimal labor compared to any strategy reliant on labor for execution.

Pruning and training: Older, yellowing leaves are removed since they may consume more energy than they produce; the removal of these leaves also promotes air flow throughout the canopy and crowns of plants. Healthy leaves may also be removed if there is too much foliage and the plant is too vegetative. Flowers may be removed from strawberry plants that are undersized when they are first planted to promote vegetative growth and increase crown size; plants that are too small and allowed to flower will produce fruits that are too small to market, as well as slow down vegetative growth. For strawberry plants that are of sufficient size, flowers may be removed to promote fruit development. Flowers that are lower on the truss moving farther from the terminal flower, referred to as the primary or king flower, may be removed to ensure that the other developing fruits on the truss will reach a marketable size. Misshapen fruits that are not marketable should be removed to promote the development of other fruits that can develop into marketable product (Fig. 2).

Pests: Strawberries are susceptible to several insect and mite pests. Aphid feeding can distort new growth, and the honeydew they excrete can promote development of sooty mold. Spider mites can diminish the vigor of plants by damaging foliage and reducing photosynthesis. Thrips feeding can also distort foliage and fruit, and they can also transmit some diseases.

Diseases: Gray mold, or Botrytis, is the most common disease in greenhouse strawberry production and can render fruits unmarketable. The Botrytis that affects fruits can infect the plants while they are flowering and will go undetected until fruits start to develop. Avoid cool, humid conditions and maintain strict sanitation to keep crops clean. If you are recirculating nutrient solution, treat the solution to suppress pathogens such as Pythium and Phytopthora.

Physiological disorders: Deformed fruits are the primary physiological strawberry disorder. When ovaries are fertilized and seeds are produced, they produce auxin and the fruits expand. However, a lack of seed development can occur as a result of several different causes. First, the pollination of the flower may not be thorough enough. Second, pollination may have occurred, but non-viable pollen or cool temperature may have inhibited fertilization of ovules and development of seeds. Additionally, if there is not sufficient pollen for a bee population, they can become aggressive in their search for pollen and damage flowers.

Another common physiological disorder is tip burn, which can occur both on the foliage, as well as on the calyx on fruits. While tip burn on leaves is undesirable, tip burn on calyces is more problematic because it can reduce the marketability of fruit. Nutrient solution with insufficient calcium concentrations can lead to tip burn. However, conditions that inhibit transpiration (high humidity, low light) or cause excessive transpiration (low humidity) can also lead to deficiencies even when there is sufficient calcium available to plants.

Harvesting: Strawberries should be harvested every day and, during periods of warmer temperatures and high light, twice per day. At a minimum, fruits should be at least 50 percent ripe; depending on the market and supply chain, fruits can get up to 75 percent ripe. While one advantage of controlled-environment production allowing fruits to ripen more on the plant before harvest, avoid letting fruits get over-ripe on the plant since these fruits will be of lower quality once they reach the consumer. When harvesting fruits, be sure to leave the calyx attached to the fruit. Some markets may also pay a premium to have a short section of the stem or pedicle attached to the fruits, but take care when packaging so that the stem doesn’t damage other berries.

Postharvest care: Once fruits are harvested, they should be cooled to between 36 to 41° F as soon as possible after harvesting and stored in 90 to 95 percent relative humidity. While many hydroponically grown crops may be hydrocooled by submersing them in chilled water, this is not a suitable practice for strawberries; fruits can be easily damaged, and the moisture can promote disease and speed the rate of spoilage. Rather, forced-air cooling should be used to reduce fruit temperature. Clamshells with holes for ventilation or punnets are both popular packages for strawberries.

Christopher (ccurrey@iastate.edu) is an assistant professor of horticulture in the Department of Horticulture at Iowa State University.

Logo courtesy of Wageningen University & Research

With a primary focus on food safety and security, Plant Sciences Group managing director Ernst van den Ende and members of the Wageningen team discussed various applications of its mission to focus on the domain of a “healthy food and living environment.” To fulfill this, research is based on the pillars of science, education and value creation, which are, he said, “combined to solve the complex issues in society.” For example: What is needed to bring a GMO to society? How do consumers accept new technologies? And, overarching all: How can we innovate more (e.g., per square meter) with less (e.g., energy), and better (e.g., safer, healthier)? “All our research programs are linked to this mantra,” van den Ende said.

He then illustrated its application to greenhouses, explaining that a high-tech tomato greenhouse can produce 20 times more than that which can be produced in the field — with four times less water. Additionally, it can use biological pest control in the closed system, resulting in less residue. All of this results in more sustainable production. “People aren’t aware that technology and sustainability are linked because they link sustainability to nature,” he said. “We need to carry that message to them.”

This is particularly important because of the challenges facing agriculture. Not only are there current global issues, such as agriculture inequality and availability of healthy food, but this will be exacerbated with the world population expected to increase to 10.5 billion people by 2100. With the impacts of climate change and our current energy and water use are added to this, said WUR Plant Pathology Scientist Geert Kessel, it is critical that agriculture’s ecological impact be reduced.

A renewed vision

The 2016 rebranding of Wageningen University and the research institutes with which it merged in the late ’90s into Wageningen University & Research has strengthened the university’s research, by furthering the blending of education, fundamental research and practical application in collaboration with the business community and social organizations.

As explained by van den Ende, it is a partnership of the public and private sector. It begins with science-driven, pre-competitive work to provide general knowledge for the industry. As the research continues and moves from theory to discovery to application, the process moves further into the private sector with privately funded, proprietary applications developed from the general research.

The purpose and goal is to provide “science with impact,” he said, explaining that to really have an impact, you have to focus on and listen to the industry. “It’s really a balancing between industry and government to find the common interests and come up with sustainable solutions,” he said.

Van den Ende gave seed breeding as an example:

• Through public funding, research has focused on molecular DNA.
• Through 10 percent private funding, the research centered in on tomatoes and potatoes.
• With more private funding and direction, research was directed to the genomics of specific tomatoes.

As such, he said, “The more private funding, the more the intellectual property belongs to industry.”

Up for debate

There is, however, a lot of debate about the value of public/private partnerships, said WUR press officer Erik Toussaint. “But that’s the beauty of the university; we welcome these debates. There isn’t one right approach; you need to use whichever is best.”

“For us, it’s really important to connect to society and do a lot of public debates,” van den Ende agreed. “I would like to have debates on facts, but very often it’s a debate on emotion.”

Just as controversial is the use of genetically modified organisms (GMOs). Kessel’s work is currently focused on developing resistance management in potatoes. Blight, as well as various bacteria, viruses and pests, all provide challenges to production. Therefore, research is focused on how to increase durability in relation to pests and diseases. The project aimed at stimulating research on genetic modification and public debate on innovative genetic techniques. As explained in the study report, “It was decided to clone and transfer late blight resistance (R) genes of crossable wild potato species (cisgenes) by Agrobacterium tumefaciens-mediated transformation without non-potato genes.”

As such, Kessel said, GMO is a tool for which one should determine benefit and risk by looking at the product in which it is used, not at the technology itself. Each application should be assessed from all aspects. “Here, we can afford not to use it,” he said. “But in poorer countries, they would really benefit from a technology like this.” For example, the study shows that if late blight were to be nearly eradicated, global potato production would increase by close to 80 million tons annually — contributing considerably to the needed additional global future food supply.

A lot of today’s plants are very susceptible to environmental conditions, and we need to study these and consider as many options as possible to increase production, said WUR scientist Gerard van der Linden. Why is this plant doing better than that one? Is there a genetic reason? Can we adapt that?

“We need to try to find the traits that breeders can use,” he said. For example, protein and fiber-rich quinoa is very tolerant to drought and salinity; it can grow in salt water and under normal conditions. As such, it has become a key focus of research for van der Linden. “This is a crop you can grow where no other crop can and produce a high yield,” he said. “So we are studying it to find out why. Maybe we can introduce that into other crops.”

Lisa is the editor of sister publication Quality Assurance & Food Safety (QA) magazine. llupo@gie.net

Integrated technology is improving for the produce market. Picture produce moving along a conveyor belt, then being picked up by delicate and adaptive robotic handles and cut with a 50,000-PSI waterjet. Together, these specialized parts constitute Heinzen Manufacturing International’s new Automated Produce Cutting System.

This system processes multiple types of produce, says Rudi Groppe, Heinzen president and CEO. “Anywhere that you’re picking and pulling and moving, this technology could [be applied],” he says.

How it works

Heinzen is the integrator of the technology, says Heinzen sales engineer Willi Ortner. The company partnered with Yaskawa Motoman, which developed the wash-down duty robot; Soft Robotics, which developed the gripper technology and end-of-arm-tooling; and KMT Waterjet Systems, which developed the waterjet.

The system’s individual components are highly specialized. In addition to its 50,000-PSI waterjet that cuts the produce, its soft robotic handles are adaptive enough to securely grab and hold fruits and vegetables and conform to the unique shapes of individual pieces.

The Automated Produce Cutting System replaces two to three employees and has a target return on investment of a year to 18 months, Ortner says. It is typically an investment for processors, but growers could use it themselves as an added step.

Recent improvements in robotics

In recent years, robotics manufacturers developing tech for produce operations have taken several steps to improve their technologies. One of the first issues the produce industry had to face was manufacturing of the soft robotics gripper, Groppe says. “You can fine-tune the design of it and the force of it, so you can actually pick up tomatoes, strawberries [and] apple wedges without any mechanical damage,” he says. “That was the first step in [replacing] some of the steps that a human does.”

Another major development was in camera technology, Groppe says. With nearly every robotic manufacturer recognizing and processing images, and more of them using a process called blob detection, an increasing number of them can integrate.

Then comes conveyance. Current systems can now run mini sweet peppers along a conveyor belt, pick them up and cut the buds off them, Groppe says. “That’s an operation now that with the gripping technology, the camera technology and conveyance, you can actually automate it, where five years ago, that was pretty much always going to be 40 people in front of a conveyor belt, picking up each product, hand-orienting and placing it,” he says.

Robotics manufacturers are consistently trying to determine how to speed up multiple steps that humans currently perform, Groppe says. In the case of strawberries, workers inspect the quality of fruit, cut them and put them on another conveyor for sorting.

What does this mean for growers and processors? “Part of the robotic solution is not replacing labor 100 percent,” Groppe says. “It’s just extending what one worker can do by four, five, six times the productivity rate of that individual.”