From The Economist:
Plants grow indoors 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 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.
The idea of abandoning the sun’s light for the artificial sort is not new. It offers plenty of advantages: no need to worry about seasons or the weather, for instance, not to mention the ability to grow around the clock (although a couple of hours a day are necessary for the plant equivalent of sleep).
LEDs offer a host of benefits over traditional, fluorescent growing lights. For one thing, they are far more efficient, which helps to keep electricity bills down. High efficiency means less heat, which makes air conditioning cheaper. Being cooler, the lights can be placed closer to the plants, so the crops can be planted more densely. The wavelengths of the light can be fine-tuned so that lettuce is crisper, or softer.
The crops grow faster, too. Philips reckons that using LED lights in this sort of controlled, indoor environment could cut growing cycles by up to half compared with traditional farming.
Among threats that American agriculture is facing are growing numbers of insects and other pests and a rising incidence of bad weather. Indoor farming is, happily, immune to both.
High-tech farming: The light fantastic | The Economist http://buff.ly/1hYZzMW