PURPOSE: To provide a system capable of supplying water suitable for growth of plants by allowing water sent from various kinds of sources to pass through a modifying unit, storing it in a storage tank, subsequently sending it to another modifying unit, modifying it, returning the modified water to a water storage tank for water spray, pumping up the stored water through a storage pump and spraying it.

CONSTITUTION: This system is designed so as to allow water collected from every available source such as a pond, a lake, a river or a well to pass through a strainer and then through a modifying unit 2 for water in a spray water tank and to supply the modified water to a water storage tank 1 for water spray and water stored in the storage tank 1 for water spray is modified by another modifying unit 4 for water in the spray water tank different from the modifying unit 2 for water in a spray water tank. The modified water is returned to the water storage tank 1 for water spray and subsequently pumped up through a storage pump. The pumped high-pressure water is sprayed or discharged from the nozzle through a hose, a surface-running pipe or an underground pipe. Thereby, water for spraying is modified so as to be suitable for growth of plants and a suitable amount of the resultant modified water is timely sprayed on a suitable place.