Singapore looks to the skies—for fields

BENJAMIN SWAN’S farm is on the fourth floor of an office building in an industrial part of Singapore. To see his crops, visitors are escorted past a door unlocked with a thumbprint and through an airlock. (“Our air is certified,” says an assistant.) Room after room is filled with plumes of kale and lettuce, evenly spaced on long trays stacked in floor-to-ceiling racks. Cables snake across the racks and ceilings, like an electrical root system. LED lights, designed to emit only the part of the electromagnetic spectrum that plants can absorb, cast a purple glow. The greens are planted in a substrate—not a speck of soil is in sight. 

Singapore is a hymn to concrete and metal. But look closely and you can see farms mushrooming across the city-state: on the roofs of malls and car parks, in schools, warehouses and even the site of a former prison. This is new. Commercial farming in the land-scarce city was phased out in the 1970s and 1980s. “Unlike virtually any other country on earth, Singapore has lost a generation of farmers,” says Bradley Busetto of the Global Centre for Technology, Innovation and Sustainable Agriculture, a UN outfit based in Singapore. Today just 720 square kilometres of land, less than 1% of Singapore, is set aside for farms. But a new crop of entrepreneurs are betting on rewards from finding idle spaces where...