Method for controlling temperature in venlo-glass greenhouse for e.g. breeding asparagus plant, in temperate zone, involves draining groundwater, and seeping and returning ground water, which is used for temperature control, to soil
The method involves providing a well to lift groundwater to known temperature from a neutral deep zone, and measuring air and soil temperature in greenhouse and external temperature by temperature sensors (8, 10). Groundwater from the zone is harvested over a surface in the greenhouse, when the external temperature falls below a preset value. An amount of groundwater is adjusted corresponding to the air and soil temperature. The groundwater is drained, and the ground water, which is used for temperature control, is seeped or returned to the soil. An independent claim is also included for a device for avoiding frost temperature in greenhouse.
