London farms fish and greens

LONDON - Inside a warehouse in industrial southeast London, farmed tilapia swim in blue tubs filled with pristine water, ready to be sold to trendy restaurants across the capital.

In an adjacent room, under pink LED lights and controlled temperatures, shoots of salad leaves and herbs grow on recycled carpet fiber fertilized with the fish waste. In this cavernous, windowless space more suited to a nightclub than a farm, the greens are stacked on metal shelves stretching to the ceiling.

It's a far cry from traditional British farms that sprawl across acres of land. But for Kate Hofman, who co-founded GrowUp Urban Farms in 2013, producing food in this 557-square-meter building in Beckton was not only clever and cost-effective. It was also a sustainable way to feed people in the city.