PURPOSE: To enable to realize the rapid and accurate control of a nutritive solution by detecting the concentrations of the ingredients of the nutritive solution in a solid medium with a FET type sensor and subsequently controlling the ingredients of the nutritive solution on the basis of the detected data, when the solid medium is employed and plants are subjected to a nutriculture.

CONSTITUTION: A solid medium 17 is charged in a cultivation bed, and plants are raised in the solid medium, while a nutritive solution controlled in a nutritive solution-controlling tank 7 is fed into the solid medium 17 with a pump 12. In the process, a FET type sensor 1 for detecting the concentrations of the ingredients of the nutritive solution in the solid medium 12 is disposed, and preferably further a nutritive solution ingredient sensor 2 for detecting the concentrations of the ingredients of the nutritive solution in a nutritive solution-controlling tank 7 is disposed. On the detected data of the sensors 1,2, etc., the valves 9, flow meters 10, etc., of plural nutritive solution tanks 8 are controlled by a general controller 18, and the necessary amounts of raw nutritive solution received in nutritive solution tanks 8 are fed into the nutritive solution-controlling tank 7 to control the nutritive solution.