My first tub I used chicken feed. My second set of tubs have oatmeal. My plan(who knows if I will follow through) is to keep 2 big bins for bettles through baby worms. I then plan to transfer the adults to grow out in the shoebox sized bins I have now. I think I'll put bran in those. Then once I have a large enough supply of decent sized adults I will start storing them in the fridge for winter.