Normal Diet

• Worms eat just about any kind of dead or decaying matter they find in the soil. They will eat dead leaves, other plant matter, and dead bugs, birds and animals. Not all kinds of worms will eat all kinds of food. In particular, some will eat plant matter but will not consume dead animals or any kind of meat, bones or grease. They also live on microscopic organisms in the soil, including fungi, bacteria and protozoa.
  
  

Soil

• It is normal for worms to consume soil as they make their tunnels and search for food, but they aren't eating the soil itself. The soil is filled with the tiny organisms that the worms can eat, but much of the soil passes through the worm's digestive system relatively unchanged. Worms also need the grit contained in soil to help them digest their food. Bits of sand and rock are captured in the worm's gizzard where they grind against one another and against bits of food that the worm has swallowed, resulting in a breakdown of the food into tiny pieces that the worm can more easily digest.
  
  

Worm Types

• Where worms live in the soil impacts their diet. Deep-burrowing worms, called anecic worms, tunnel as much as 10 feet into the soil, chewing through everything they come across on the way. Endogeic worms live below the surface, but not very deep. Their tunnels tend to run parallel to the surface, usually angled slightly downward, and they consume soil that is usually rich in dead vegetation. Worms that live at or very near the surface of the soil are called epigeic worms. They consume some soil but mostly limit their diets to the plant litter they find as they crawl above the soil.
  
  

Potting Mix

• Worms may be able to eat some things contained in potting mix, but they are not likely to be able to live on such a diet for long. Sterilized mix may not contain any nutrients that worms need, but a mix that is rich in organic matter will sustain worms for a long time. If worms are to be kept in an environment filled with potting mix, it is best to supplement their diet with dead leaves, kitchen scraps and garden waste.