PROBLEM TO BE SOLVED: To provide a cultivating method with potential control, using a metabolic response of a microbial flora derived from a cultivation bed, capable of (1) inhibiting the generation of greenhouse gas from the cultivation bed, and (2) improving the plant productivity by removing plant growth inhibiting factors.SOLUTION: The potential control method for cultivating includes forming the conductive carbon material-containing cultivation bed by containing a conductive carbon material, whose element ratio O/C obtained from a Cand Opeak area by a surface analysis by ESCA is in a range of 0.01-0.30, in the cultivation bed, imparting a given potential to at least a part of the conductive carbon material-containing cultivation bed, and maintaining the conductive carbon material-containing cultivation bed near the given potential in a condition that an electrolysis of water is prevented, thereby inhibiting or promoting the generation of a specific metabolic system-related substance in the conductive carbon material-containing cultivation bed.
