To provide vegetables with low nitrate nitrogen having low content of nitrate nitrogen owing to hydroponics, and free from giving harmful effect to a human body.
A supply and circulation system 1 of culture solution comprises supplying to a perforated hydroponic pipe whose each hole is planted with a plant, from a culture solution supply pipe 21 with a pump 13 through a control valve 111 from a culture solution storage tank 11, and collecting culture solution collected from a culture solution collecting pipe 23 in the culture solution storage tank. Plants are grown by supplying culture solution for a fixed period, collected through stopping supply of culture solution before a harvesting time and cultivated by supplying water from a sprinkling water storage tank. As a result of this, it is possible to consume nitrate nitrogen accumulated in a plant body and lower nitrate nitrogen concentration to 450 ppm so as to harvest.
CHEN CHIA-YU
JPH06105625A | 1994-04-19 |