Compost-ology Worm
Harvesting Worms - Dump & Sort


  • Very large sheet of heavy plastic
  • Goose-neck or similar desk lamp with 100-watt bulb
  • Plastic container for worms
  • Plastic or metal garbage can, corrugated carton or heavy-duty plastic bag for vermicompost
  • Fresh bedding

Spread the plastic sheet on the floor or table and dump the entire contents of the worm bin on the plastic. Make about nine pyramid-shaped piles. You should see worms all over the place. If the light is bright enough, they quickly move away from it and head toward the center of each pile.

Let the piles sit for five to ten minutes. Gently remove the outer surface of each pile. As you do so, worms on the newly exposed surface will again react to the light and retreat toward the interior. By following this procedure one pile at a time, you will find that when you return to the first pile, worms will have disappeared again and you can repeat the procedure.

Eventually the worms will aggregate in a mass at the bottom of each pile. Remove the vermicompost that collects on top of them and put the worms in the container you have ready for them.

According to Mary Applehof, vermicompost from this sorting process will vary in consistency, depending upon how long the bin has been going, how much and what kind of garbage was buried and how much decomposition has occurred. Some of the most recently buried food waste can be put right back into the fresh bedding. The rest can continue to vermicompost in the plastic bag or garbage can you assembled earlier for conducting the harvest.

Vermicompost from plastic bins may be excessively moist. If water drains onto the plastic sheet, or if the pile slumps down from the excess water, you know it is too wet. Sorting through this sticky material is not pleasant and it is very difficult to get the worms out.

Appelhof has placed such soggy vermicompost in a heavy-duty corrugated container and let it sit in a dry place for several weeks. So much excess moisture evaporated from the surface and through the walls of the box during those weeks, the compost lost 15 pounds, or about one-third, of its original weight. After losing this much water, the vermicompost was well-established and earthy-smelling. It had a crumbly texture perfect for use in the garden.

A large number of cocoons and baby worms should be present in the vermicompost from which worms were harvested. If you're going to use your vermicompost as top dressing for your house plants, be sure that cocoons and baby worms are not in that mixture.