A British Lighting engineer, Chris Paton, has developed the so-called Seawater Greenhouse that combines traditional polythene tunnel design with plant that provides desalinated water for irrigating  crops. The system is ideal for growing cash-crops; vegetables, flowers and ornamental plants in coastal regions  of countries with arid and semi-arid climates. It offers the poosibility to switch horticultural production in such countries from the mains water supply to using the inexaustable supply of sea-water (actually increasing as the polar ice melts). 

The first country to take up the operational system was the United Arab Emirates where today on a desert island off Abu Dhabi, there is the first full-scale Seawater Greenhouse up and running and growing vegetables. In Europe, the Mediterranean region has been targeted as providing suitable areas for installation. As part of an EU backed project, coordinated by the Region of Sardinia, further trials will take place in North Africa (Tunisia o Morocco).

The Seawater Greenhouse uses evaporative cooling as its principle; seawater and sunshine are the raw materials to produce fresh water for irrigation, cool air and photosynthetically active light for plant growth. The thermodyamic model developed for the system indicated that in optitmum conditions the prototype Seawater Greenhouse could produce up to 100 litres of fresh water per m2 of greenhouse, sufficient to irrigate the greenhouse and a larger area besides. The role of the developers is to trasfer this technology plus a few exclusive components but to encourage the use of local made components wherever possible.

The cost of cooling and humidifying a Seawater Greenhouse is substantially cheaper than to provide supplementary heat and light to a greenhouse in a cooler climate, the opposite of what we are taught about in convention greenhouses! For a detailed description of the Seawater Greenhouse, look out for a forthcoming article in “Flortecnica”  www.flortec.it   E-mail: flortec@flortec.it