I use rice bran and it seems to work pretty well for me. I also put some powdered egg shells in every now and then to moderate the PH and to give them some grit. But let me say this, when you think you have it all figured out, something will happen to let you know you don't. Good luck and keep trying. I sst out to raise enough worms so that I would not have to buy any next year. I feel that I have reached my goal now.