LONDON: Sealed growing tunnels which produce up to eight crops a year of spinach or rocket, or more exotic and trendy stir fry ingredients like pak-choi and chilies, are being built in Britain to supply supermarkets.

The revolutionary growing method involves a computer controlled atmosphere with enhanced carbon dioxide to promote maximum growth 365 days a year. A single crop can be produced to order in 40 days.

The British invention, which has been patented, has great potential for export to countries without enough land or water. It can also be used as a controlled environment for scientific experiments or on a larger scale for football pitches, so players and athletes could get used to playing in humid or other adverse conditions.

But the current plan is to concentrate on agriculture, where one tunnel 42 metres long can grow as much as an acre of ground. Planning permission has been given to build 60 tunnels at three sites near Brands Hatch in Kent, the Isle of Wight, and Ockenden in Essex, south-east England.

A condition of a farmer buying one of the tunnels is that he takes one acre of land out of normal production to return it to nature.

The condition has been imposed to ensure that the bio-diversity of the British countryside is improved by the new growing method, which Greengro, the company building the tunnels, believes is the most environmentally friendly farming system available.

The tunnels, costing $267,750 each, are double skinned and sealed to prevent water and heat loss and produce up to 10 times the crop that could be grown in a field. Because the growing compost and the tunnels themselves are sterilized, no pesticides are needed.

Excess heat gathered in the polycarbonate tunnels in the day is recirculated at night to keep the crop warm. For the whole of last winter, extra heating was needed for only seven hours.

The idea of producing pesticide-free high quality vegetables to order has attracted all seven of the UK’s supermarket chains. It also cuts out the criticism of them for flying exotic vegetables halfway round the world for British consumption when poor people in the countries concerned are short of land and often hungry.

Peter Wilkinson, former director of Greenpeace UK, and botanist David Bellamy are both involved in Greengro and have carried out environment impact assessments.

Ben Gill, president of the National Farmers’ Union, was also impressed. “I am still looking at the details, but in a country short of land, this system has a lot going for it.

The Greengro system involves filling growing tubes with coir, the waste dust from husks of coconut, currently imported from Sri Lanka; however, the company is looking for a local growing medium to avoid the imports.—Dawn/The Guardian News Service.