An innovative way for heating greenhouses using solar energy during the winter for summer crop production

The development and construction of the "Eden" greenhouse, a walk-in tunnel oriented east-west with standing black PE water tubes on the north side forming a "wall of water " was successfully used to grow basil (a summer crop) in winter, without using a conventional fossil fuel heating system. The simple, sustainable, nonpolluting, no emissions system for growing warm climate crops in winter by raising the temperature using only solar energy is a low cost investment allowing one to avoid all energy costs for heating during winter. The advantage of the location of the "water wall " is that there is no shading on the crop and there is no physical disturbance to the workers. A relatively large amount of water can be kept in the wall (8 m³ water in a 30 m length walk-in tunnel) which absorbs the solar energy during the relatively hot days and releases the heat during night, creating favorable temperatures for crop production. Orientating the tunnel in an east-west direction has a considerable advantage over north-south orientated tunnels. The basil yield grow in the "Eden" greenhouse was greater the yields obtained by using PE mulching, horizontal water tubes, thermal screens and double layers of PE covering material. This method made it possible to grow basil free of winter diseases without needing chemical spraying of fungicides. Depending on the climatic conditions there is a possibility of using one or more passive heating methods (such as PE mulching, water tubes, thermal screens or double layers of PE covering material) to produce high yields of excellent quality.