>>2597486Hmm....good luck! I'm not sure how well they will do. I've never seen anyone grow on pure coco. I make my bags with sawdust, vermiculite and wheat bran. I grow blue oyster and lion's mane. Not sure if elm oyster likes a different sub. The coco should hold a decent amount of water, but adding vermiculite will hold more. Remember mushrooms are 90% water. You need a good reservoir if you want large mushrooms and several flushes. I've also only run unsupplemented once and got terrible results. You should have a food source in there like wheat bran.