<；P>；PROBLEM TO BE SOLVED: To provide a hydroponic method for plants by which autointoxication is hardly caused with more practicality than a conventional method. <；P>；SOLUTION: The hydroponic method in a nearly closed system for the plants includes reducing the concentration of a growth inhibitor exuded from roots of the plants into a nutrient solution by electrolyzing the nutrient solution. The concentration of the growth inhibitor exuded from the roots of the plants into the nutrient solution may be reduced by electrolyzing the nutrient solution for the plants circulated in the nearly closed system. When the nutrient solution for the plants circulated in the nearly closed system is electrolyzed by providing the constitution, effects of the electrolysis, i.e. degrading effects on the inhibitor can be exercised on not only the vicinity of electrodes but also the whole culture solution and the electrolytic effects can uniformly be exercised. <；P>；COPYRIGHT: (C)2009,JPO&INPIT
