Although vertical farms producing leafy greens are receiving most of the press coverage, there are a variety of other crops being being grown and innovative growers are finding these crops to be profitable.
When you think about a vertical farm what picture comes to mind? Ricardo Hernandez, horticulture professor at North Carolina State University, said most people think of vertical farms as indoor growing operations that produce leafy greens, primarily lettuce.
“There are both small and large leafy greens vertical farms,” Hernandez said. “Some of them are going out of business and some new ones are opening up. All of them have similar challenges.
“The main challenge is that even though they can produce a lot of leafy greens because they are able to stack the plants, there is a bottleneck in terms of how fast they can produce the crops. The bottleneck is tied to the plant genetics. With the current plant genetics and cultivars that most vertical farm entrepreneurs are using, it is very hard to outperform the lettuce crops coming out of the field. This is especially the case if the field conditions are suitable to grow lettuce such as in California and the southern part of Arizona during the winter.”
For many of the cultivars being grown in the field, including butterhead, red leaf lettuce and baby greens, the same seed is being used in vertical farms.
“In order for the leafy greens produced in vertical farms to actually gain significant market share, the genetics have to be changed in those plants,” Hernandez said. “This can come through conventional breeding or gene editing or through targeted breeding using molecular tools. A new set of cultivars is needed, a new set of genetics that are specific for indoor farms. Right now we are using the genetics that are good for field production. These field cultivars have high plant uniformity in terms of growth under a large variability of environmental conditions. The field genetics enable plants to look the same even if there is a lot of variability in the environment.”
Because vertical farms provide a stable environment, Hernandez said the types of genetics that are needed are specifically for an environment that can be controlled. The genetics for field crops of maintaining high uniformity and minimizing large variability are not a concern with vertical farms.
“Unfortunately, the market for breeding companies to develop varieties specifically for vertical farms is small,” Hernandez said. “There is not an established market for vertical farm growers. There hasn’t been a significant effort by established breeding companies to start developing cultivars specifically for vertical farms. Maybe some startups will be able to develop new cultivars or university researchers may be able to give those efforts a boost.”
Cost of production
One of the major hurdles with vertical farms is cost of production.
“There is a lot of technology and utilities associated with producing leafy greens in vertical farms,” Hernandez said. “That cost of production is very high compared to the leafy greens grown on the West Coast even when the shipping costs are added on.
“There actually are some vertical farms making money. Some of those are in boutique markets. These growers are able to get more money for a head of lettuce than the competing product that comes from the field. However, it is going to be difficult for growers who are selling to boutique markets and who receive a premium price for a head of lettuce to break into the mass market. Most consumers are not willing to pay the higher boutique prices.”
Hernandez said in order for vertical farms to acquire a significant share of the market, they are going to have to bring down the price of lettuce so more people will be willing to pay for the product.
Making money with transplants
One area of vertical farm production that Hernandez said growers can be profitable is producing transplants or starter plants.
“I’m convinced based on economic studies that we have done in my lab, using vertical farms or indoor growing is economically viable for growing transplants or starter plants,” he said. “Growing transplants is a very economical way to successfully adopt vertical farm production. These starter plants are a high value product and they can be grown under very high density in vertical farms, even higher than they can be grown in a greenhouse. These transplants are inserted into the current supply chain and will be sold to greenhouse and field growers who will produce the end products.”
Hernandez has started a transplant vertical farm, Grafted Growers, with his business partner John Jackson. Hernandez said growers looking to produce transplants in vertical farms should choose crops considered to have the highest value.
“These would be transplants that benefit the most from being grown indoors,” he said. “The clean controlled environment of a vertical farm can ensure a very high germination rate and a lot of plants can be produced in a small area. The controlled environment of vertical farms also provides a desirable outcome including finished plants that flower sooner or plants that have more dry mass.”
Hernandez said the uniformity and quality of transplants grown in a greenhouse may not always match transplants grown in vertical farms.
“If there is good solar radiation levels, greenhouse growers can produce very good transplants,” he said. “If growers are trying to produce those transplants in greenhouses during the fall or winter, they may have to supplement the natural light levels or the quality of the transplants may not be as good. There may be a difference in quality and uniformity between seasons.
“Growing transplants in a vertical farm the quality of the transplants is consistent no matter what the outdoor conditions are. Comparing transplants grown in a vertical farm with transplants grown in a greenhouse during the winter, which is when many transplants are grown, the vertical farm transplants usually have a higher dry mass and are more uniform.”
Hernandez said a grower producing transplants during the winter may be able to match the quality of vertical farm transplants if a lot of supplemental light is used.
“It’s not only the amount of light that is important, but also the quality of light,” he said. “Even though transplants grown in a greenhouse may be receiving enough light with the use of supplemental light, depending on the light spectrum the transplants could end up stretching because they are planted at a high density.
“In a vertical farm the transplants can be kept from stretching by controlling the light spectrum so that they can be grown compact in a very high density. By taking the sun out of the equation and controlling the plant growth with artificial light eliminates the potential for stretching.”
Having the right vertical farm setup
Hernandez is quick to caution growers considering starting a vertical farm that different crops require different production setups.
“Growers can create a lot of microclimates and have poor uniformity when they have the wrong vertical farm setup,” he said. “The vertical farm that works for leafy greens may not work for transplants because the requirements for transplants uniformity are different from those for leafy greens. If growers don’t have the right vertical farm to grow transplants, it’s not going to be easy and it could become a bigger problem.
“Growers need to listen to the plants and know what the plants need. Growers can incorporate a lot of technology, including robotics and sensor control, but if they are not listening to what the plants need, the technology will only deliver marginal improvements. The most important thing in a vertical farm is the plants. Everything else is just details.”
For more: Ricardo Hernandez, North Carolina State University, Department of Horticultural Science, Raleigh, NC 27695-7609; firstname.lastname@example.org; https://hortenergy.cals.ncsu.edu.
This article is property of Urban Ag News and was written by David Kuack, a freelance technical writer from Fort Worth, TX.