There are four hydroponics mutations that can be rolled for but can't be applied for various reasons
Created by: Exxion
The thorny, creeping spread, vine spread, and parasitic mutations cannot actually occur. The first three are trivial fixes; they are simply broken because the strings that pick_mut() returns that correspond to them are not the same ones apply_mut() looks for.
Parasitic is slightly more broken. apply_mut() doesn't seem to have code to apply it at all, no matter what string it is passed. It wouldn't really be hard to add, though.
I'd go ahead and fix them all except it might be a somewhat substantial balance change and I'm not sure if any of them were left out on purpose.