When plants draw water from their roots to nourish their stems and leaves, they produce an electric potential that could be harnessed as a renewable energy source. However, like all living things, plants are subject to a circadian rhythm—the biological clock that runs through day and night cycles and influences biological processes. In plants, this daily cycle includes capturing light energy for photosynthesis and absorbing water and nutrients from the soil during the day and slowing its growth processes at night.