PURPOSE: To provide an economical and practical method for automatically supplying water and/or a nutritive solution required by a plant in response to the energy quantity of solar radiations, and to provide a device for performing the same.

CONSTITUTION: A solar radiation type automatic nutritive solution supply control method is characterized by converting the energy of solar radiations into an electric current, converting the electric current into an electric current having a frequency, dividing the frequency, and automatically supplying a prescribed amount of water and/or a nutritive solution to a plant, when the divided frequency reaches a prescribed integrated value, and a practical device for performing the same.