A prototype growing system invented in Great Britain promises major production advantages in climates ranging from temperate to sub-tropical and semiarid. Called 'Greengro Farming System' it has been invented by Michael Dufton, Co-Director of Unigro Ltd of West Kingsdown, Kent. Trials after 12 months are encouraging. The modular system is based on a hermetically sealed 400m2 tunnel unit clad with a double skin of polycarbonate with an 8cm gap between the two skins. This significantly dissipates heat in the summer and reduces energy costs in the winter. The air is filtered making the growing area sterile and therefore pesticide free. The requirement by the crop for water is greatly reduced and the water and nutrient levels are constantly monitored. A computer controls temperature, light, humidity and CO2 levels over a 24 hour 'daylight' production regime. According to Licensing Executive, Angus Padfield, capital costs of the new system are quite high but compared to high- tech glasshouses, significant savings in the cost of energy can be made and running costs are much lower. More importantly, the increased cropping potential is very significant using soil-less cultivation with vertical stacking of plants to maximise the growing space. The substrate being utilised for vegetable production is a mixture of coir (coconut fibre) and animal waste. The Company claims that a production of 45,000 kg of strawberries in 5 crops is possible during one year and as many as 8 salad crops. The system could be very quickly and simply adapted to ornamental crops.

The costs of a 400m2 unit are about Euro 239.000-279.000 depending on total number of units built with a pay-back on investment of about 20%-25% over 5 years. Initial plans are to produce high value crops much in demand in England such as chilli peppers and oriental vegetables. www.greengro.co.uk