Growing the World’s Food in Greenhouses

Can greenhouse crop production become efficient enough to produce food for the masses? Neil Mattson and his research team are tackling the challenges.

Neil Mattson, School of Integrative Plant Science, Horticulture Section, spent his childhood on a farm with flower and vegetable gardens. “If you know how to grow your own food, you’ll never go hungry,” Mattson recalls his grandmother, who grew up during the Great Depression, saying. “That ethos has carried with me.” And it has carried into his research projects, which aim to better understand controlled environment agriculture (CEA)—the cultivation of crops in controlled environments such as greenhouses, plant factories, or vertical farms.

Mattson is particularly interested in CEA. He says, “It integrates technology and agriculture and enables year-round production of high quality products.” For example, one can produce 20 to 50 times more lettuce per acre in a greenhouse than in a field in California.

Even so, there are challenges and drawbacks to growing crops in controlled environments, including the amount of energy and labor costs required. Given the challenges, one of the main questions driving Mattson’s work is essential: Is it realistic and economically viable to scale up CEA to feed the masses? “I’m trying to understand the pros and cons of this higher tech production system and want to understand its constraints and improve upon the constraints,” Mattson says.

LED Lighting for Greenhouses

Mattson is principal investigator of GLASE—the Greenhouse Lighting and Systems Engineering Consortium—which in 2017 received $5 million in funding from the New York State Energy Research and Development Authority (NYSERDA). The seven-year project aims to develop greenhouse lighting and control systems, as well as management practices, to reduce energy use while increasing crop yield.

For this project, Mattson’s team studies the use of LED lights. LEDs are significantly more energy efficient than legacy lights and also have more control capabilities—such as adjusting light intensity and spectrum—whereas legacy lights can only be turned on and off. Currently two-percent of lit areas in greenhouses use LEDs. One barrier is the high upfront cost of the new technology. Since it’s new, growers don’t fully understand how to use its capabilities.

“The hardware has advanced more quickly than our understanding of the underlying plant physiology and how to operate the lights to promote plant yield and quality,” Mattson says. “We’re beginning to understand plant responses to lights and developing better control strategies for energy efficiency.”

Another aspect of the program is to study how carbon dioxide (CO2) interacts with LED lighting. Carbon dioxide is commonly used in commercial operations to make photosynthesis more efficient thereby reducing the need for supplemental lighting. “There’s still a lot of research needed to figure out the control strategy for carbon dioxide for specific crops given lighting and ventilation conditions,” Mattson says.

Growing Lettuce, Tomato, and Strawberry Crops in New York Greenhouses

The GLASE project specifically aims to understand the use of LEDs to best grow three economically important crops for New York State: lettuce, tomato, and strawberry. To do this, Mattson and his collaborators begin by collecting data in enclosed indoor environments, with no outside light. That drives greenhouse research, where Mattson tests hypotheses on campus greenhouse facilities with supplemental light. Finally, the researchers bring the technology to industry partners in pilot projects, to both drive adoption and collect real-world data.

Given the applied nature of the research, GLASE is already organizing an industry-funded consortium, which currently has 13 industry members. “When the project ends, we want it to be self-sustaining from private support, since there will continue to be new technology and challenges and questions in plant lighting,” says Mattson.

CEA for Urban Areas

In a second project, funded by the National Science Foundation, Mattson and collaborators are looking at the scalability of urban controlled environment agriculture, specifically high-tech plant production in greenhouses and vertical farms. Given the increased public interest in locally grown food, the project looks at the environmental and economic implications that this nascent industry could have on five metro areas—New York, Chicago, Seattle, Los Angeles, and Atlanta.

Urban CEA has several benefits. Production is closer to the consumer, which could increase freshness and taste. It is more land-use efficient. It is more water-use efficient, thanks to hydroponic systems that capture and reuse nutrients. It creates local jobs.

Yet Mattson says, “The energy or carbon footprint ends up being the main sticking point.” Part of the project is working with economists Miguel Gomez and Chuck Nicholson, Charles H. Dyson School of Applied Economics and Management. Gomez and Nicholson are running life cycle assessments to compare current energy costs and carbon footprints to ones that would involve urban CEA.

“Because of climate change, declining water availability, erratic temperature patterns, we’ll need to grow more of our perishable crops in protected environments.”

For example, what is the cost of growing lettuce in a field in California and shipping it thousands of miles to New York City? How does that compare to growing lettuce in a greenhouse or vertical farm in New York City?

Though the project is still in its early stages, the researchers have already found that growing lettuce in a greenhouse in New York may have a lower carbon footprint and higher water efficiency than field production and shipping 3000 miles from California. However, it doubles the cost of production.

“There are these environmental and economic tradeoffs,” Mattson says. “What environmental components are most important? Is water use efficiency or carbon footprint the most important? That may depend on where you are located around the country.”

The project will continue to do analysis in the various metro areas to better understand the impact of these choices. The goal is to ultimately provide this data to inform policy and planning in municipalities.

To address these higher costs, the project also looks into ways to manipulate light spectrum in order to adjust plant quality attributes. The researchers are focusing specifically on increasing levels of carotenoids, organic pigments that contribute to eye health. Changes in lighting could also affect other attributes, such as getting thinner leaves, earlier flowering, and taller plants. “If it’s going to cost more, there are things we can do to add value,” says Mattson.

Going forward, making CEA more energy efficient and lowering cost will be increasingly important. “Because of climate change, declining water availability, erratic temperature patterns, we’ll need to grow more of our perishable crops in protected environments,” he says.

In the future, Mattson wants to expand his research to other crops and fruits that could be produced indoors. He also hopes to work with food scientists to further understand nutritional attributes and the human experience with food, helping grow better produce. He says, “Ultimately, I want to get Americans to consume more fresh produce and help us be healthier.”