Hydroponic apparatus

摘要

A nutrient solution is circulated through a pip connection between a nutrient solution tank 2 and a culture tank 3. A water circulation passage is formed between a water storage tank 1 and the nutrient solution tank and has placed therein a heat exchanger 5 for heat exchange with the nutrient solution, and a valve 6 controlling water flow therethrough. A valve 10 controls flow of water into the nutrient solution. This arrangement controls a rise in the nutrient solution temperature due to the circulation of the nutrient solution and an increase in the solution concentration due to evaporation.