A friend of mine used to only use worm castings (basically worm poop! LOL) and the local 'hard' water (lost of minerals in it). He did not raise the worms Himself, but I had an Uncle that raised worms for bait, fed them used coffee grounds, flour (wheat), and general table scraps (leftover veggies and meat scraps). My friend grew His weed in coco coir indoors under HPS lamps. The weed turned out great, very fragrant and potent.