"Plant boy"? A childrens book, I don't remember the titile. It is bugging me?

[Fatefinger]

It's a children's book where this kid turns into a plant boy, His skin turn green and he starts acting like a plant in what I think is a school science experiment he does on himself, and government people get involved in some way. I read it as a kid, it recently popped in my head and can't get it out of my head. Normally I would stop thinking about it but I can't. I need to know the name.