These urban farmers build indoor towers out of salad greens.

Vertical farming startup AeroFarms grows crops indoors, where it can control light, temperature, and humidity. It doesn’t use soil or 95 percent of the water usually required to produce greens; instead, AeroFarms plants its kale and arugula in a proprietary cloth material and sprays their roots with a nutrient-rich mist. The cloth was invented by Cornell professor Ed Harwood, who joined forces with David Rosenberg and Marc Oshima to co-found the Newark, New Jersey– based company in 2011. AeroFarms, which has raised more than $100 million, sells its salad greens to grocers including Whole Foods and FreshDirect. It says its facilities are nearly 400 times more productive per square foot, by output, than a traditional farm, thanks to artificial intelligence, which helps the company continuously refine its growing process. So the founders hire for more than just green thumbs. “We look for problem solvers,” Rosenberg says. “There’s an element of: Let’s hire brilliant people, and then we’ll find a place for them.”