Greenhouses, an asset for crop development
Greenhouses have been used for centuries to protect many crops from climate hazards such as frost, excessive temperatures, wind or rain. The main advantages of greenhouse crops are better water efficiency and better pest control. Greenhouses allow for higher yields and therefore require smaller areas than open-field production. The climate control of greenhouses is a balance between incoming solar radiation, heating systems used to compensate for heat loss, and losing heat due to ventilation. During the day, the greenhouse is an energy collector that allows temperatures inside the greenhouse to be higher than those outside. On winter and spring nights, especially in cold climatic regions, heating is necessary to maintain favourable temperatures for crop development.
The greenhouse is therefore defined and designed according to the requirements of the crop, its geographical location and the economic imperatives of the farms. Since 1996, greenhouses have become increasingly important in vegetable production in France: the surface area of high greenhouses increased by 7% between 2000 and 2010, reaching 7,431 ha, including 6,100 ha of greenhouses with little or no heating. The CTIFL survey of cold and poorly heated greenhouses1 [JZ1] showed that producers were waiting for experiments to improve the climate control of greenhouses.