An elegantly simple idea is making waves in some of the hottest and driest places in the world, using seawater to cool greenhouses and create the humidity plants crave.

Seawater Greenhouse chief executive Charlie Paton has developed greenhouses which, rather than contributing to groundwater depletion, utilize water from the ocean through desalinization.

He tells www.freshfruitportal.com his model is "restorative" as opposed to extractive with a lattice of cardboard, similar to a large piece of Weetabix, added to one end of a convential greenhouse or polytunnel.

Seawater is pumped into the lattice with a fan overhead, allowing water to evaporate in the heat with the resulting fresh water condensing and cooling the greenhouse, which provides humidity for the plants.

Light fantastic

Paton, 62, thinks of himself as a 'techie' rather than a scientist with a background in electrical light design for theatre, television and rock concerts.

In fact, he already has a major invention to his name - remote control motorized lights used for the West End musical Starlight Express and the farewell tour of British rock band, The Who in 1982.

He trained in theatre design at London's prestigious Central School of Art and Design where lighting became his obsession.

"In the late 60s and 70s I was passionate about light and what it does. It is the number one driver of everything, it's responsible for everything. It's one of those things that people don't know much about. But plants know all about light."

He explains plants only use a small part of the visible light spectrum, reflecting back green light and absorbing red and blue to photosynthesize.

Charlie Paton

His fascination with light, and regular holidays with his wife to Morocco in the late 80s and early 90s, were the seeds for the seawater greenhouse idea.

"It's an agricultural country, most people are farmers and very poor because of lack of rainfall. It has the Sahara Desert in the south and the Atlantic Ocean in the west."

Desert inspiration

Paton started to think about how he could harness some of the natural resources that countries like Morroco have to improve horticulture.

He got together with scientist and engineer Philip Davies to create a prototype, with the help of Professor Phil Harris who acted as their horticultural advisor.

Unlike many high-tech modern commercial greenhouses where the temperature is controlled within a few degrees using up vast quantities of energy, seawater greenhouses use solar panels.

He adds it is cheaper to install and run a seawater greenhouse in a dry arid country than heat a conventional one in northern Europe using gas.

"Our greenhouses work with the climate cooling the air to wet bulb temperatures offering 80-90% humidity levels. Most plants thrive on high temperatures on the condition humidity is also high."

The prototype

The first seawater greenhouse was built in Tenerife in 1992 with the help of  European Commission (E.C.) funding.

The Canary Islands, once known at the 'Garden of the Gods', suffers from arid soil damaged by excessive abstraction of groundwater. It was the perfect site to test the protoype.

He and Davies were able to successfully grow crops in the greenhouse by exploiting high solar radiation and prevailing wind drive.

However, despite the pilot's success the idea went into cold storage when the E.C. realized its application was best suited to dry, hot developing countries outside Europe.

Paton's funding to take the initiative further disappeared and everything was put on ice for the next eight years. But his luck changed in 2000 when his invention won the London Design Museum's 'Design Sense' award for best practice in sustainable design.

The prize was a GBP40,000 (US$63,562) check which enabled Paton and Davies to pursue the initiative again. Their next project was on Al-Aryam Island in Abu Dhabi when they constructed a multi-span polytunnel for growing cucumbers in 2000.

This was followed by a joint project in 2004 with Sultan Qaboos University in Oman to reclaim abandoned agricultural land on the Batinah coast, where soil and water salinity had made it impossible to grow crops.

The seawater greenhouse proved to local farmers and Arabian Gulf enterprises it was possible to cultivate this area again.

Grand designs

Paton said he is now looking for more active investors to take his greenhouses to Somalia, Egypt, Algeria, Curaçao island off the Venezuelan coast and Cape Verde off the West African coast.

He also believes that the Senoran Desert in Mexico would be ideal for the next commercial development of his greenhouses.

"Mexico is very switched on and there are some very clever growers. The country is currently suffering the worst drought ever which looks set to continue for a while."

www.freshfruitportal.com