Following a hunch, the author discovered (or re-discovered?) that all plants carry an electric charge relative to the ground. This charge is more or less constant regardless of the size of the plant - a kind of `background voltage` in nature. This electric charge suffuses the entire plant, from its roots to its leaves and fruit. It was measured between a chrome-plated pin inserted into the plant (the positive terminal) and an iron spike driven into the ground (the negative terminal).