I know that human cells are best at around -50 millivolts. People that are ill tend to have higher voltages, around -20mV.

Maybe plant cells have a critical voltage value at which their growth accelerates ?

Maybe raw food is better for you because of the higher voltages as compared to cooked food ?

It's certainly a really interesting topic.

I may try it with tomato plants later this year, one with an earth-battery and one without.

Also, pots that are painted on the inside with that special paint that contains copper, they grow faster and larger, perhaps the copper helps conduct electricity around the pot better ?