You feed worms what you have and what they like to eat. Red wigglers which spend almost there entire lives in the top 4 inches of soil like to eat decaying plant material. Be careful with to much grass clippings etc because they will heat up and burn the worms. My composters love eating Mango peel and apple cores. They like any soft decaying material. Avoid dairy, meat and fat as they will attack rodents before the worms get a chance to finish.