Hi, I haven't trried it with Grindals. I use Gerber's instant baby oatmeal. I make 4 or 5 small piles of it in the 5 inch square plastic box that I use, moisten them, and stand back. Once the colony is established is almost impossible to overfeed it. Heavy feeding is one of the keys to being successful with Grindals. Good luck with your worms. Bill