CHAPTER SIXTEEN

What a Plant Is, Electrically

Before asking whether electricity can help a plant, it helps to know that a plant is already an electrical thing. This is not a fringe idea. It is in every textbook of plant physiology.

The living battery

Every living plant cell keeps a voltage across its outer membrane, the inside negative to the outside, typically by more than a tenth of a volt. That is a larger voltage than most animal cells maintain. The cell spends a considerable part of its energy pumping charged atoms, chiefly hydrogen ions, across the membrane to keep that voltage up, and then uses it as the driving force to pull in nutrients. When a root takes up potassium, nitrate or phosphate from the soil, it is doing electrical work.

Signals

Plants also send electrical signals. In 1873 the English physiologist John Burdon-Sanderson recorded an action potential, the same kind of electrical pulse that runs along an animal nerve, in the leaf of a Venus flytrap as it snapped shut. In the early 1900s the Indian physicist Jagadish Chandra Bose showed similar signals in the sensitive plant, Mimosa, and argued that all plants have something like them. He was partly mocked for it in his lifetime, and he was largely right.

Modern instruments have confirmed it in detail. When a caterpillar bites a leaf, a wave of electrical and calcium activity spreads from the wound through the plant’s veins within seconds to minutes and switches on defensive chemistry in leaves the insect has not yet touched. A team led by Masatsugu Toyota filmed this in 2018, the wave glowing as it traveled, and published it in Science.

Fields

Plants respond to external electric fields as well. Growing roots bend in a field, a response called electrotropism. Pollen tubes steer by electrical gradients. And the flower itself carries a charge: in 2013 researchers at the University of Bristol showed that bumblebees can sense the weak electric field of a flower and use it to tell which blossoms have recently been visited.

What this does and does not prove

All of this establishes one thing firmly: it is entirely plausible that an applied electric field or current could change how a plant grows. Anyone who says electroculture is impossible in principle is wrong.

But plausibility is not proof, and it carries a warning. A system that runs on finely regulated voltages of a tenth of a volt is not obviously improved by an outside jolt. An engine runs on sparks, and that does not mean more sparks from outside make it run better. Whether a given electrical treatment helps, harms or does nothing is a question only experiment can answer, one treatment at a time.