AeroFarms, the world’s largest industrial farm, is contained within a windowless, gray building in Newark, New Jersey. In its 70,000 square feet of floor space—not all of it yet in use—kale, arugula, baby salad greens, and herbs grow in trays without soil; their roots grow down through water-misted air. It’s a clean, painstakingly engineered facility, where outside visitors must go through the hygienic paces before entering, moving through a series of antiseptic footbaths; into a sanitary uniform complete with booties, shopcoat, and hairnet; and finally through a particle-removing blast of pressurized air. Only then can one take in the sight of thousands of plants growing under neon lights in 80-foot-long racks stacked 36 feet high, arranged in aisle after aisle.

Vertical farms like AeroFarms, of course, have their critics. But proponents say they are the future, and judging by the sheer volume of vertical farm-related headlines, you might conclude that those proponents are right—that all we need to do is sit back and watch while conventional agriculture withers away, farms revert to wildland, and sparkling, non-polluting growing facilities become a new part of our cityscapes.

AeroFarms

It was this summer, after all, that the SoftBank Vision Fund, whose investors include the Public Investment Fund of the Kingdom of Saudi Arabia, Apple, Foxconn, Qualcomm, and Sharp, anted up $200 million—said to be the largest ag-tech investment ever—to help San Francisco-based company Plenty realize its vision of building vertical farms in every city with a population of greater than one million. Meanwhile, Global Market Insights, a research firm, recently predicted that the vertical farming market will be worth $13 billion by 2024, with more than 70 percent of that value coming from indoor farming operations like AeroFarms and Plenty.

It’s easy to see the appeal. By isolating themselves from the outside environment, vertical farms can go pesticide-free. They use very little water; AeroFarms claims that it can grow its greens using only five percent as much water as a conventional farm. They can shorten food’s voyage from farm to plate from hundreds or thousands of miles to mere steps. On the downside: Facilities are expensive to build, and they mostly replace free sunlight with expensive electricity—so much electricity that it may well wipe out the carbon advantage of fewer food miles.