A grey warehouse in an industrial park in Indiana is an unlikely place to find the future of market gardening. But it is, nevertheless, home to a pristine, climate-controlled room full of eerily perfect plants.

They grow 22 hours a day, 365 days a year in 25-foot towers, untouched by pests and bathed in an alien pink light.

Critical to this $2.5m techno-Eden, run by a firm called Green Sense Farms, are the thousands of blue and red light-emitting diodes (LEDs) supplied by Philips, a Dutch technology firm. The light they give off is of precisely the wavelength craved by the crops grown here, which include lettuce, kale, basil and chives.