Rising lettuce in a vertical farm makes use of drastically much less water. Is it an answer for a warmer local weather?
Posted On February 26, 2023
Farmers in Yuma, Ariz., like to tell visitors that they produce 90% of the country’s winter greens.
So if you’re eating a salad in Buffalo, Boston or Cincinnati, there’s a pretty good chance the lettuce was grown near the U.S.-Mexico border with water from the Colorado River.
But the river is in peril.
Too many people are drawing from it, and the decades-long drought in the West is so bad that if states like California and Arizona don’t make drastic cuts to their water use, the federal government has warned the river could stop flowing past the dam at Lake Mead within two years.
But here’s a provocative question: What if we needed far less water to grow food, and what if farmers did it indoors?
Inside a vertical farm
In San Francisco, 650 miles northwest of Yuma, an agricultural startup called Plenty is doing just that.
Leafy greens like bok choy, lettuce and baby kale grow inside a warehouse on towers that rise five meters off the floor. A rainbow spectrum of LED lights shine on the plants for most of the day, offering them ideal growing conditions.
“We bring the plant in and we just say, ‘how do we get the best results, period,’” says Plenty co-founder Nate Storey. “We keep the growth rate at maximum the whole way through. Their lives are very short, but they are very good.”
Vertical farms like this one are part of a young but growing industry. They’ve popped up in cities like Denver and New York.
Storey says growing lettuce in a vertical farm uses about 90% less water compared to traditional field agriculture. The company recycles nearly every drop it uses on the farm and as the technology matures, the water savings could get even better.
“It’s a big deal,” Storey says. “This is like a reckoning for the United States because we have relied on the Colorado River for so long. But other parts of the world have already gone through this structural change. There are parts of the world where desertification has already taken place and their water resources are gone or depleted. For folks that have lost their water resources, this is something to look at.”
The Colorado River is facing a crisis
That doesn’t mean vertical farming will solve the dire situation on the Colorado River. Between 70% to 80% of the river is allocated to farms in seven Western states.
Six of those states recently gave the federal government a plan to reduce their water use. But the state that draws the most from the river, California, didn’t sign it. As negotiations drag on, it is clear that major cuts will be coming to the region’s most important water supply.
“We are challenged with a dynamic climate out there. It’s not stable anymore,” says Murat Kacira, director of the Controlled Environment Agriculture Center at the University of Arizona.
The Tucson campus includes greenhouses and a vertical farm. Indoor growing will play a more significant role in agriculture as the water crisis grows more urgent, Kacira says. “It will be a piece of the puzzle, but it will not replace field agriculture.”
The cost of growing indoors
That’s because there are still many challenges growing indoors at a mass scale.
During a recent visit to the university greenhouse, a system of pumps were feeding nutrient-rich water into the irrigation system. Ventilation fans were on to keep the air fresh. A vertical farm uses those systems, too. Plus, the lights are on all day long.
Kacira describes the electrical energy needs for indoor farming as substantially higher compared to growing crops outdoors.
“That’s the challenge that the whole research and technology development is trying to address,” Kacira says. “That’s the bottleneck of crop production.”
There’s also a huge unmet demand for skilled workers trained in automation, he says.
Vertical farming In San Francisco
At the Plenty facility in San Francisco, Storey is realistic about the farm’s power consumption. “It is a chief criticism of this industry, one that we’re very well aware of,” he says. “We’ve got to pay the power bills.”
But Storey predicts there will be more renewable energy available in the future than fresh water. “For us, it’s a calculated bet,” he says.
Inside the warehouse, a powerful robotic arm effortlessly grabs one of the five-meter towers and feeds it through a cutting machine.
The journey from seed to harvest can be up to twice as fast as growing lettuce outdoors, Storey says. The greens that are harvested at this facility will be packaged and sold in nearby grocery stores at a price comparable to organics.