guy i know is adding lithium meds to his plants in the form of salts. So I did a quick search an haven't found other people trying this. His thinking is the plants take it up and make it into a more absorbable form . sounds dangerous to me .... for both the plant and him lol
It will take up heavy metals, that said, how in the hell could you regulate the dose. I've "overdosed on lithium, was a very unstable time in my life. Not a good idea imo.