Ninth-generation farmer Paul Moyer is looking at produce sanitation in a whole new light. By combining ultraviolet rays and a hydrogen-peroxide vapor, he, in partnership with Dr. Keith Warriner, a food scientist at the University of Guelph in Ontario, have created a process that they say kills 99.9% of mold, mildew and pathogens.

Clean Works, which is based in the Niagara region of southern Ontario, recently won the International Association for Food Protection’s Food Safety Innovation Award for the Clean Vertification sanitation process.

Moyer, co-owner of Clean Works, encountered issues with sanitation when his farm entered the candy-apple business. In 2015, the industry encountered a listeria outbreak that killed seven people and hospitalized 34. “We weren’t implicated, but it certainly affected us,” Moyer says. “And then I said, ‘Huh. There should really be something that cleans produce better.’”

Since chocolate and caramel don’t mix well with water, Moyer started looking into creating a new way to clean produce. “I’ve always thought that water acts [as] more of a vector for pathogens than it does [as] a solution for pathogens,” he says. “Whatever’s in the water spreads to the other fruit, so if there’s one infected fruit, it’ll spread to the other fruit or vegetables.”

After experimenting with a few different options and working closely with Warriner, he found a process that not only sanitizes produce, but increases shelf life by 25%.

“We doubled the efficacy of just the hydrogen peroxide and UV light. So, it’s a very, very effective way of killing both pathogens, mold and mildew. So, essentially, the hydrogen and the oxygen radicals are very powerful in this chamber. And then that chamber, will break down pathogens from E. coli, salmonella and listeria, as well as mold and mildew that a lot of people refer to as a rot."

Produce Grower: What need are you hoping to fill with this new technology?

Paul Moyer: I wanted to have something that didn’t use water. There are a lot of fruits and vegetables that don’t like water. Apples aren’t a problem, but then you get into peppers or tomatoes or blackberries or raspberries ... you can imagine, you just can’t really put them through water very well. So I wanted to create something that was totally, totally different — a different way of thinking about how we clean things.

So, I was thinking totally differently and I took it a totally different way.

PG: How does the whole process work?

PM: So, essentially, it all works together. That’s kind of the magic of it. When you mix the UV light with the hydrogen peroxide with the ozone gas, you’re creating an atmosphere around that piece of fruit. So, it doesn’t have to be underneath the light for it to be effective. It would be like you walking into a room but you’ve got a whole bunch of things going on. And the mixture of the gases and so on is what is affecting the mold and the mildew and the pathogens and the viruses on that piece of fruit. And because they’re microscopic, this is all chemistry that’s happening on a microscopic level. It’s not going to hurt the fruit because it’s a fairly large piece of organic matter. But when you start talking about viruses and mold and mildew spores, they’re teeny tiny and it’s very, very powerful. And that’s why it doesn’t affect the fruit in a bad way, but it certainly affects the pathogens and the mold and mildew and the viruses.

PG: What sorts of produce would this system be effective on? Would it include greenhouse crops like tomatoes, cucumbers and microgreens?

PM: We’re getting a 3.49 log on microgreens, so it works on lettuces and it works on all sorts of fruits and vegetables with different results but certainly surpassing the traditional results of water by 1,000-fold. So, 1 log is a 90% kill and 2 logs is a 99% kill. Three logs is a 99.9% kill. So far, far, far more effective. When you get a 1 log reduction you think, “Hey, that’s pretty good." Traditional wash methods — if you put it underneath the sink and washed it and rubbed it a little bit, you’d get a 0.5 log fill.

PG: What sort of testing process has this gone through and how have you verified the efficacy?

PM: Not only has it been accepted by the scientific community because we’ve had a number of papers that have been published in the industry, but we won the International Association for Food Protection’s Food Safety Innovation Award and we beat out Monsanto and 3M and all the big players, so that was a pretty big deal.

PG: How can this technology be used in the greenhouse industry?

PM: As the industry changes and so on, everybody is being affected by food safety. So, the more intervention steps or hurdles you put into that process, the safer the consumer deems the product to be. There have been issues in the past. And nobody wants to have an issue. This is an intervention step. A lot of people are saying. “We’re fine. We’ve never had a problem.” The problem is the science is changing very quickly. At the turn of the century, everybody was very concerned about dairy products and then it was meat products and now it’s coming to the produce world. And not only is it helping with the food safety aspect, but it’s increasing the shelf life.

PG: How does the technology help monitor and document results?

PM: Sooner or later, people are going to say, “You put this intervention step in and that’s really great. But when did you do it? When did this occur, and did it hit the parameters that it’s supposed to hit?” So, we can monitor the ozone and when we did it and so on. When we ship caramel apples into the U.S., you know, some of our customers are saying, “We’d like to see the fact that you put your product through these processes.”

When Austin Webb enrolled in Pittsburgh’s Carnegie Mellon University in 2016 to pursue his M.B.A., he knew that artificial intelligence and robotics would be a part of whatever business he ended up in. At the time, he says, the “entrepreneurial fever” had hit him completely.

“I went to Carnegie Mellon specifically to try and start a company because I believe AI and robotics can help change the world,” he says. “In month one there, I met this tall, lanky guy named Austin, who said, 'Hey, do you know much about vertical farming?' and I said, 'Hey, my name's Austin too and yes, I do know a little bit.' What we [eventually] found was this industry-wide struggle to make the economics work.”

That Austin is Austin Lawrence, who previously worked on another ag-tech start-up and now has a master’s degree in robotics from Northwestern University. Lawrence, along with Webb and his brother, engineer Brac Webb, co-founded the business in 2016 under the name RoBotany. The tech was first tested in two locations on Pittsburgh’s south side, where greens were grown and sold by retailers such as Giant Eagle and Whole Foods, as well as local restaurants. Ahead of the launch of a 60,000-square-foot vertical farm in Braddock, Pennsylvania, the company rebranded to Fifth Season, although it retains the tagline “powered by RoBotany.”

According to Webb, the main thrust of the business is two-fold. First, it aims to bring cleaner, more sustainably grown food to the Pittsburgh area before building farms in other locales. Secondly, the company wants to use technology not only to grow leafy greens, microgreens and herbs, but to create a new agriculture job that’s fueled by the same technology powering the farm.

“We really wanted to jump in and make vertical farming, which we think can be this wonderful solution to solve food waste and food health and food access, and to take that solution and make it an economic reality today as opposed to just a pipe dream for the future,” he says.

How Fifth Season grows

To dive deep into the field, Austin and the other co-founders first considered comparing the idea of vertical farming and how it currently works vs. how it would work. The two trial locations were, in that sense, a proof of concept not just to potential investors, but also for the business’ concept itself.

According to Webb, Fifth Season’s system is mostly built out of proprietary technology that combines AI and robotics with engineering. The facilities feature 30-foot tall towers, LED lighting, data-collecting sensors that gather information from plants throughout the growing process and various automated features that limit human contact with the plants. The farm still employs laborers, but Webb says the majority of their current employees are engineers — for a specific reason.

“Engineers are working on everything from hardware, software, firmware in embedded systems so that the system is able to tell the but hardware what it’s doing,” he says. “It’s all connected end to end. And they are working with our food safety specialist, our operations specialists and our plant management because our operations are integrated with our technology.” Webb adds that the amount of connectivity is what allows the farm to maintain the standards of food quality and safety that the founders want. An estimated 60 workers will be employed.

According to grow lead Danielle Ferreira, the key to growing at Fifth Season is the “recipes” for leafy greens and herbs that have been developed to provide the exact input each plant needs. Additionally, none of the crops are grown with pesticides.

“It’s a massive step up. You have a recipe and your inputs are always the same because you are controlling it 100%,” says Ferreira, who previously worked at Nature Fresh Farms, Metrolina Greenhouses and Green Circle Growers. “If you have 100% of the control, you have consistency [in the crops].”

“On a day-to-day basis, with any changes we make, it’s a continuing improvement,” she says. “Everything is being considered.”

The data collected by Fifth Season makes growing easier, too, she says, when compared to a more traditional controlled environment.

“We have an awesome R&D team developing those recipes for those farms; [they] are being tested in the farm and validated,” she says. “Even small differences — say, a slight change in the intensity of lighting — can make a huge difference. Knowing the details of what works best, you can see the results in the quality of the crops.”

As for picking Braddock as the facilities location, Webb says one benefit is that their farm doesn’t take up too much space compared to an outdoor farm or other businesses. By their estimates, the 60,000 square-foot farm produces the equivalent of 2.5 acres of outdoor growing space.

The second location is where Fifth Season leadership identified Braddock and the broader Pittsburgh area needed more locally grown produce. Braddock particularly needs a jolt. According to City Lab, 30.3% of the city’s residents currently live below the poverty line and the area has struggled to find an economic identity as the steel industry declined.

“The technology is what creates this level of freshness. It’s what allows us to change the distribution. Technology is the enabler.” - Austin Webb

“A big part of how he selected Braddock is looking at the food distribution system and acknowledging that it’s broken — that people are disconnected from its food,” Webb says. “So, we can go into a city like Braddock, which is a food desert, and it’s a great spot to start the decentralization and transform that harvest so that within a few hours, it’s in your hand, your salad or on your shelf.” He notes that Braddock has a history of innovation but has lost all but one of the steel mills that defined it for so long.

“We want to be part of the new era of innovation,” he says.

Emphasizing technology

Webb says that Brac, his older brother and co-founder, started tinkering with computers and programming since he was a teenager.

“We’ve always been connected to technology,” he says. “And a lot of [Brac’s] older work is around satellites and the 'internet of things.' That’s where software and hardware really come together and you’re moving hard assets.” He says that seeing how his brother's brain power could be used to utilize that technology was what put AI and robotics onto his radar.

According to Webb, the three years between the company’s founding and the Braddock facility’s launch were spent largely developing the technology and learning more about what worked and what didn’t on other farms. He says that several prototypes were built — some of which influenced the system that’s currently in place now — and that others at least provided value in helping Fifth Season do R&D across the board. For instance, some early prototypes were used to test what crops might work in the system, as company leadership didn’t want to limit the potential product line to just one or two items.

“We want to be able to provide many more products than that, giving people options based on their lifestyle,” Webb says. The next step was using prototypes to grow product and get consumer feedback well before the actual farm opened. One lesson they learned was that emphasizing the local aspect of production — Webb says 70% of consumers will pick local over 18% preferring organic — when presented with either option.

Data is an essential part of the business too; Webb says that they are taking “tons of data points every minute.” Every tray in the system, he says, has a unique ID number so it can be located at any time and traced throughout the growing process and when it gets to the package.

“That allows us to make improvements in quantity and yield,” Webb says. “That level of traceability allows us to create the peace of mind that consumers are wanting, especially right now where lettuce is the highest cause of food-borne illness and we have all of these food safety recalls.”

He notes that data always works hand-in-hand with the company’s use of AI: The amount of data collected would be a massive task for a team of workers to break down, but something that a computer can do much more efficiently.

“It creates these feedback loops in our closed-off system that allows us to get feedback and connect data by connecting dots,” Webb says.

Continuing the build

The future of Fifth Season, he says, is expanding outside of Braddock. Like other operations — such as Revol Greens, Bowery Farming and Little Leaf Farms — Fifth Season’s growth plan involves building new locations in different cities. According to Webb, emphasizing technology on the farm makes taking it elsewhere — be it the U.S. South, the Pacific Northwest or abroad — more feasible than if the business was centered around a single crop.

“The technology is what creates this level of freshness,” he says. “It’s what allows us to change the distribution. Technology is the enabler.”

That includes reaching retail and food-service partners too — particularly amid a string of E. coli outbreaks stemming from field-grown lettuce. The traceability, Webb says, creates a sense of comfort and transparency for the end consumer.

“I don’t imagine [doing this without data] because anyone who isn’t doing something different — maybe just building some greenhouses — you’re not really innovating to move the dial when it comes to quality, hyper-locality, food safety or price and affordability,” he says. “We definitely view it as this technology creating this whole new open door, whether you’re thinking about it as a business owner or end consumer.”

“We can go into a city like Braddock, which is a food desert, and it’s a great spot to start the decentralization and transform that harvest so that within a few hours, it’s in your hand, your salad or on your shelf.” - Austin Webb

Moving forward, the plan is to go somewhere new; locations are to be determined. According to Ferreira, the recipes used at the Braddock facility should be the same at any new facility, with minor tweaks once the farm is built and data is collected in that new environment.

Expansion will require the Braddock farm to work, and will also likely demand more capital. At its inception, Fifth Season was incubated through Carnegie Mellon; they’ve since raised $35 million with assistance from Columbus-based venture capital firm Drive Capital. Webb says the goal isn’t to raise as much money as possible. (In comparison, California-based farming company Plenty raised $200 million in its last round of funding, while New Jersey-based operation Aero Farms raised $100 million last summer.)

“The thing that’s really nice about our approach — which I’d describe as a disciplined walk-the-walk — is an ability to do more in less time and with less capital,” he says. “We haven’t had to go out and do this huge mega raise that puts us and our employees in a bad spot." He says the technology, instead of being a way to seek out investment, is a way to not have to.

Still, Webb doesn’t define Fifth Season as solely a technology company or even just a grower. Instead, he uses the term “consumer-experience company.” By investing in Braddock and ideally other communities, Webb hopes the company can play a part in democratizing food and creating change.

“It’s taking something that was viewed as a commodity and making it part of their lifestyle,” he says. “That’s the most fun part.”

Controlling insect pests is one of the most important priorities for greenhouse food crop producers. One of the challenges in controlling insects on food crops in greenhouses is a lack of pesticides labeled for use on edible plants grown in controlled environments. To reduce the potential for insect pest problems to develop, preventing them from entering and establishing in the greenhouse is essential. Insect screens are an important tool in excluding pests, and this article will highlight important considerations for their use.

Effective screening

The first consideration for installing insect screens is to determine what part(s) of the greenhouse will be covered. For crops that are less susceptible to pests, screening the air inlets (such as pads) can provide sufficient exclusion to make a difference. However, for facilities looking for exceptional exclusion from screens, more comprehensive coverage is required. In addition to the air inlet, exhaust fans and vents also need screening to maximize exclusion. If screening is installed, be sure to use air lock doors and seal gaps and leaks. Without doing this, the screens are rendered less effective with these opportunities for insect infiltration.

Selecting screens

The first step to take when selecting an insect screen to install is to consider the target pest or pests that are to be excluded. Screen selection is directly related to insect size, which varies among the most common pests. For example, a leafminer is over 600 µm wide, while thrips are around 200 µm wide. The smaller the insect size, the smaller screen opening required. For example, a screen that is sufficient at excluding whiteflies will not be sufficient for screening thrips. However, if whiteflies are the primary pest, then do not use screen intended for excluding thrips; this will reduce airflow or increase the screening area to maintain adequate airflow. In addition to differing in hole sizes, the materials used differ. Most screens are made of nylon, polyethylene or a blend of polyethylene and acrylic. These materials can be used to create screens that are woven or knit with different hole sizes, or a film with holes perforating it. When selecting screens, the investment cost can be related to the durability. Note that longer-lasting products initially cost more.

To reduce the potential for insect pest problems to develop, preventing them from entering and establishing in the greenhouse is essential.

Maintaining air movement

When considering insect screen, maintaining adequate airflow in the greenhouse is as important as effectively excluding insects. Whenever screens are installed in a greenhouse, they restrict the airflow. In an actively cooled greenhouse, the reduced airflow can cause fans to work harder and potentially burn out. When screens are installed, in order to maintain airflow, the area of the openings in the screen must equal the area that is being screened. A screen simply installed flush over an air inlet would not provide adequate ventilation. However, there are several ways to install screens to accommodate the extra material needed to maintain airflow. A lean-to, as seen in Fig. 1, or other enclosure can be built around the openings to be screened. Alternatively, screens can be pleated, like an accordion, to increase the surface area of the screen to maintain airflow. Screens are best suited for greenhouses using some type of active ventilation. However, screens can be used in passively ventilated greenhouses, but care must be taken to minimize the effect of increased temperatures in the greenhouse on crops.

Screen maintenance

Once screens are installed, don’t forget to maintain them in order to sustain sufficient air flow. As screens collect dust and dirt, airflow will be reduced from blockages resulting in openings getting clogged. Regular monitoring will indicate when cleaning is needed. Screens should be washed at a time when venting is not necessary, since the water on screens from washing will reduce airflow and increase the temperature in the greenhouse. Avoid using brushes or pressure washers, as these tools can increase the openings in the screen which, as a result, will render them less effective at excluding pests.

The take-home message

Non-chemical approaches to insect pest control are an important tool in protected greenhouse-grown food crops. Insect screens can be an effective tool when the right equipment is covered, appropriate screen is selected and maintained and adequate greenhouse airflow is ensured. Whether including screens as part of a new build or retrofitting old facilities, consider insect screens for improving pest control.

The author is an associate professor in the Department of Horticulture at Iowa State University. Reach him at ccurrey@iastate.edu.

Better yields, better quality, lower cost. That’s what we’re all looking for when it comes to crop production and bottom line revenue. The same is true when it comes to lighting technology for greenhouse-grown produce. We want lighting that’s going to help us grow bigger and better faster — but it needs to provide the best outputs at the lowest cost and energy use possible.

The market has been flooded over the last few years with LED technology and lamp options that provide new opportunities to ramp up your output and business. For a minute there, it seemed like LED tech options were only going to keep getting cheaper and more plentiful. Bush- and Obama-era energy efficiency standards aimed at phasing out inefficient bulbs, such as incandescent-standards that were set to go into effect Jan. 1, 2020, sent investors into the LED market and drove innovation.

However, in September 2019, the Trump administration announced it would roll back these efficiency standards — a step which could slow the demand for LEDs in the overall market and the investment and innovation into building better and more efficient horticultural lighting. Hopefully that will not be the case, but there are concerns the move may slow LED cost reduction and hinder scalability for indoor farmers.

Several states are currently fighting the rollback, and as of February, the National Resource Defense Council, along with coalition partners, filed two lawsuits challenging decisions by the U.S. Department of Energy related to this issue. So, keep your eyes peeled.

Potentially unfavorable deregulation aside, the mad dash by many new investors to get into the legal cannabis growing market seems to continue to be a big driver for a lot of horticultural lighting innovation. But eventually, I suspect we’ll see a lot more tomatoes being grown under lights than cannabis.

There’s no doubt, given current population trends and limitations on productive farmland (and clean water), that localized CEA and greenhouse food production are a must. While CEAs have seen big growth the last few years, trends do seem to be shifting towards more greenhouse production. Growers want to harness as much natural sunlight as possible — saving on energy costs — using supplemental artificial lighting to boost production or push them over the finish line faster.

While lettuces and baby greens are well suited to tightly stacked enclosed systems, tomatoes, many herbs and other important produce crops are not. Greenhouse production, with more open vertical growing systems, are simply more realistic for many crops. Given the vertical nature of the future of greenhouse food production, there’s also a shift away from measuring yield success by square meters or feet, towards cubic meters or feet. Given these pivots, greenhouse technology, especially in the HVAC arena, needs to advance right along with horticultural lighting. Optimizing all of your greenhouse facilities is a top priority.

Intercanopy light supplementation for vertical production and adjustable illumination in LED rigs have been leading trends in application innovation. Yet, it’s not all about LEDs all the time. Recent research by Phillips touts hybrid lighting systems for tomato production, blending LED and HPS configurations. Whatever your opinion on LED versus HPS, growers forging ahead with lighting investments also need good standardized data on exactly which lamps, at what output and spectrum mix, will best grow the most sustainable and profitable form of a given crop. Chances are, there may be many different LED lamps, or other HID options, and configurations that will work for you in one way or another. But without firm standards in place, it can be challenging to easily compare different lamps on the market.

Luckily, trends in horticultural LED lighting are moving towards deeper and more meaningful research into exactly how to light specific crops for efficiency, the very best product and profitability. Not only that, but we’re also seeing more research on how to manipulate produce flavor, color and nutrition with specific lighting regimens or spectrums.

See the recent research released by Fluence and Döhler that explores how lighting affects both flavor and smell of greenhouse grown basil. You can check out their case study with Peace Tree Farm here. Fluence also recently released new data on boosting greenhouse tomato yields with their LEDs. At Phillips’ GrowWise Center, a lot of energy is going into researched “grow recipes” of lighting regimens for specific produce crop quality and harvest goals.

And of course, you can always look to my alma mater, Michigan State University, along with Cornell University, Colorado State University, University of Georgia, North Carolina State University, and Utah State University (I’m sure I’m leaving some out) for the latest cutting edge lighting research for edible and floriculture crops.