it all depends on the compost pile: what's in it? how long has it 'cooked'? I wish I could grow on compost piles(especially my biodynamic compost)...we always have kitchen waste trying to grow- and doing an amazing job at that!...even on unfinished compost...and worm castings? hah! try a baitshop per shovel of the worms already there...it's insane-how many worms!