The product they release is called worm castings, or vermicompost, and it's what's left behind as earthworms eat their way through old leaves, food scraps, and other materials that are found in a ...

The leaves fall, thousands of tons of them and three members of a demolition squad break them down. The first are the earthworms which eat through the leaves and mix them into remains into the soil.

Josh Hartwig is the host of Discover Nature and a media specialist for the Missouri Department of Conservation.