“I like to call this the cathedral.” So says Matt Barnard, CEO and cofounder of the vertical farming startup Plenty. We’re standing in a room at the company’s headquarters in a former electronics distribution center in South San Francisco, staring up at glowing, 20-foot high towers filled with perfectly formed kale and herbs. The company isn’t the first to build an indoor urban farm in a warehouse. Aerofarms, for example, grows greens in a 70,000-square foot former steel factory in Newark, New Jersey. Nearby, Bowery, another tech-filled indoor farm, grows what it calls “post-organic,” pesticide-free produce. But Plenty, which has received $26 million in funding to date from investors such as Bezos Expeditions and Innovation Endeavors, believes that it has the technology to grow food more efficiently–at the same cost or less than crops grown in the field–so it can more easily scale up to supply supermarkets around the world. Unlike most other indoor farming companies, which typically grow food in rows on shelves, Plenty grows food vertically–each plant popping out of the side of a tall, skinny tower. Lights are also arranged vertically rather than pointing down from above. While Aerofarms claims to grow 130 times more produce than conventional farming in a given area, Plenty claims to grow 350 times more than conventional farming.“Shifting to the vertical plane makes us usually four to six times more efficient spatially than a stacked system–[like] someone like Aerofarms or someone like Bowery,” says cofounder and chief science officer Nate Storey, who previously founded another vertical farming company called Bright Agrotech. “Ultimately, we’re able to have a much higher space-use efficiency than we could if we were trying to stack our equipment. So everything in the system serves that end, which is how can we pack more plant production into the space without sacrificing plant health.”