Not to mention the thought of smoking or ingesting something that was grown in Cat litter is just wrong. I know it would be new but that just sounds nasty!
what exactly is this plant physiology book? have you ever cleaned a cat box it kinda clumps together.lol plus I think hydroton is expanded more then cat litter.
There is two types of litter, clumping and non-clumping. Non clumping would work, but clumping wont. Clumping litter is bentonite based.