Bioelectric potential is caused by ion stream in vegetation tissue. This potential could be applied as a speaking plant approach (SPA) technique. In this study, the potential of white radish is measured in an ethyl alcohol atmosphere to establish the SPA technique. The absolute summation (vm1) of the potential for 1 min is adopted to analyze the potential characteristic, and the frequency of an LED panel and the ethyl alcohol concentration are adopted as parameters. Moreover, the absorption capability (Pa) of white radish for the alcohol is derived and its relationship with vm1 is examined. As a result, it is clarified that there is a correlation between vm1 and Pa, namely, Pa increases with vm1. The distribution of Pa in relation to the light frequency and concentration indicates a normal distribution, and it is considered that the potential is related to the growth rate of vegetation. Other summations vm30 and vh1 for 30 min and 1 h are also adopted to derive their relationship with the absorption capability (Pa) for the substance.