What to Feed: Acceptable foods are: fruit rinds, cores and peels, grains, vegetative matter, egg shells, coffee grounds and filters, tea leaves and bags. Worms like materials high in cellulose such as sawdust, leaves, paper, and cardboard. Some people say that worms like breads, but –in my experience– they will not touch bread. Chop your food wastes before feeding your worms, and the material will be digested more quickly.
What Not to Feed: Unacceptable foods are oils, cat and dog feces, meat, cheese, butter, animal products, fish, and paper printed with colored inks.
How to Accumulate Food: I keep a Folgers can under my sink to accumulate scraps for my worms. This prevents the scraps from drying out, smelling up my kitchen, or rotting too fast before I use them for worm food.
How to Feed: Remove the lid from the bin, remove a top layer of the bedding material, then place the kitchen scraps on the surface. Cover the scraps with the top layer of bedding, then replace the lid on the bin.
How Much to Feed: The amount of scraps to feed will depend on the size of your bin, the number of worms you have, etc. — but a good place to start is a few tablespoons. Worms are expected to eat a pound of food per week for every square foot of surface space in their bin. The real test of the correct amount of food is attention to what remains at the end of the week. (See: Check the Bin for Over-Feeding.)
How Often to Feed: Worms should be fed about once a week. It is much better to give them small amounts of food on a weekly basis. However, I have heard of people who feed every 3 weeks or so and who say they have had no problems.
Check the Bedding for Moisture: At feeding time, check that the bin is not accumulating liquids from the foods. If it is, use proper bedding to soak up the liquid. Make sure the bedding is still damp. If it is too dry, fill a spray bottle with water, and use it to thoroughly wet the bedding. Don’t wet it to the point that the bedding is dripping with water.
Check the Bin for Over-Feeding: At feeding time, look for excessive accumulation of undigested foods. If you have a lot of food which the worms did not digest, you must monitor the situation. Adjust quantity of feeding, and moisture of foods.