How do you create a sustainable, economical vertical farm?

Princeton University’s Vertical Farming Project aims to improve the sustainability of vertical farm production systems for commercial growers.

The lack of accurate information related to vertical farming production was one of the main reasons that Dr. Paul Gauthier decided to start the Vertical Farming Project at Princeton University in Princeton, N.J. Gauthier, who is Associate Research Scholar in Environmental Plant Physiology and Modeling, began the project in April 2016 after he saw an increasing number of growers considering starting vertical farm operations.

“I noticed that a lot of the information related to hydroponic growing was coming from the 1990s and there was a lot of misinformation,” Gauthier said. “I decided to address some of the issues that growers were having by starting a vertical farm project and showing growers how to improve the production systems. There was a lot of information about growing in greenhouses, but very little information on growing in a vertical farm. With the Vertical Farming Project I wanted to investigate the challenges that vertical farm growers would face in the future including manpower, technology and sustainability, which is one of my main goals.”

Training vertical farm technicians

While Gauthier was interested in helping growers develop better hydroponic production systems, he was also interested in training Princeton students who could go on to help advance the vertical farm industry.

“Because of the interest in vertical farming and more people looking at starting vertical farm operations, there is going to be a demand for high technology jobs to operate these facilities,” Gauthier said. “When I started this project I wanted to create a program for training students about this technology. Nutrient film technique (NFT) and deep water culture are the two most common vertical farm production systems currently being used by growers. These are the systems that my students are working with and doing different projects.

“One of the questions that we wanted to answer when we began the project was how long does it take a grower to break even and to start making money. We began looking at how to create a business plan using a vertical farm inside a building and not a greenhouse. We wanted to determine how long it will take using a vertical farm for a small company to break even. We also wanted to look at energy consumption and water consumption.”
While Gauthier has seen a lot of excitement from his students about growing vegetables, he said they don’t necessarily understand the limitations to growing plants.

“A typical way that I interact with the students is to have them work on the vertical farm for at least two months,” he said. “They come to the farm almost every day to monitor pH, temperature and EC. I ask them to look at the changes in the plants. I want them to learn how a vertical farm works and how plants react to changes in pH, EC and temperature.

“I then ask them to come up with their own projects based on their own interests. Every time we grow a new crop in the vertical farm we collect information on water, energy and nutrient consumption.”

Undergraduate student Jesenia Haynes is working on a research project to determine the carbon footprint of vertical farms. Haynes is studying the impact on the environment producing kale and lettuce in a vertical farm versus a conventional farm.

“What would happen if there were 10,000 vertical farms?” Gauthier said. “Would that be something that is good for the environment? Jesenia came up with a project to try to determine the impact growing a hydroponic crop could have on the environment. She is working on determining a way to calculate the amount of carbon that is created by producing a kilo or about 2 pounds of lettuce in a vertical farm. Undergraduate student Seth Lovelace is monitoring plant growth with sensors and another student will be studying the production of strawberries in a vertical farm.”

Designing an efficient, sustainable production system

The vertical farm system that Gauthier designed incorporates both deep water culture and NFT systems equipped with broad spectrum white light LEDs.
“Because I’m a plant physiologist, I know that plants use light from a broad range of wavelengths and not just blue and red,” he said. “I was focused on incorporating white light with a full light spectrum. The bottom part of the vertical farm system is a deep water pond used for research. In the NFT troughs we are growing lettuce, basil, cilantro, kale, peppers, snow peas and strawberries. I am also growing wheat, barley and edible flowers.

“The reason I am focusing on a variety of crops other than leafy greens is that we can’t feed the world on just lettuce. In order to be able to feed the world using vertical farming, as a lot of people are claiming, then we have to be able to change peoples’ appetites. There are a lot of other crops besides lettuce. If we can change the flavor by altering the taste, we may be able to change the appetite and diet of a lot of people. Then we may be able to change the way we feed the world.”

One of the major issues Gauthier is studying is finding solutions that make vertical farming more environmentally friendly.

“One of the big issues with vegetable farming is creating waste,” he said. “All of this waste has to be treated. One of the main wastes of this treatment is green water. We don’t want this green water to be released and to pollute more areas.”

Another area of interest for Gauthier is to incorporate vertical farming into architectural building design.

“We are cooperating with some of the architects on campus to find a new solution to integrate vegetable farming into architectural design not just for food, but to also integrate vegetable farming into the design of new buildings to make vegetable production a part of our everyday life,” he said. “These buildings provide a controlled environment. Putting vegetable farming into a building could benefit what is already inside the building.

“The environmental impact aspect of vertical farming is the challenge for the next five years. It is especially important to do before the industry and its operations get too big. Once the industry grows too large it will be very difficult to investigate. What we are trying to determine and to push is to develop sustainable systems that are affordable for everybody to begin a startup. We don’t want people to have to upgrade to a more sustainable system. We are trying to develop a sustainable system right now.”

For more: Paul Gauthier, Princeton University, Department of Geosciences, (609) 480-2690; ppg@princeton.edu; https://verticalfarming.princeton.edu.

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