Composting Worm Care

Question: What do composting worms eat? How do we clean out the bin?

Answer: Composting worms -- red wigglers -- eat just about everything -- fruit and vegetable peels, pasta, rice, bread, coffee grounds, tea bags, trimmings from the garden. (Just as in a regular compost pile, however, don't add dairy products, oils, or meats, or dog or cat manure.) Eggshells can be added to the bedding (typically shredded, moistened newspaper), but they take a long time to decompose. Put in an apple core. It will soon have worms poking out it of just like the drawings in children's books. Kids love this!

Every six months or so, harvest the worm castings and put the worms into fresh bedding. It's important to do this, or the worms will die as their waste products, or castings, build up. One method is to move the finished compost to one side of the bin, then place fresh bedding and food waste in the other side and let the worms migrate naturally, over time, to the fresh food and bedding. You can also dump the entire bin contents onto a plastic sheet and allow students to separate the worms manually.

Worm castings are a rich, dark brown, have a pleasant earthy smell and somewhat resemble coffee grounds. They are high in nutrients and can be added to houseplant soil mixes, incorporated into garden beds, or spread on the top of soil as a mulch, with the nutrients seeping in with repeated waterings.