Harvesting of VermiCompost
Vermicompost contains worm castings as well as small amounts of decomposed organic matter broken down by microorganisms and partially decomposed bedding soil. Vermicompost with a larger proportion of castings can be obtained through leaving the worm bin unattended (no more addition of kitchen scraps) for a long period. This is a self-destructing process to some degree. As the worms convert all the remaining material in the bin to castings, they will also die off both because of the diminishing food supply and the increasing toxicity (to themselves) of their closed environment from the increased supply of castings.
Various methods of harvesting vermicompost (separating the worms from the finished compost) are documented in "Worms Eat My Garbage". Two perhaps less messy adaptations of these methods are described here.
Method One
Vermicompost ready for harvesting should have a high proportion of worm castings and all of the food waste at least partially broken down.
All of the old bedding is pushed over to one side of the bin and a temporary partition is put in. New prepared bedding material with food added to it is placed in the vacated side of the bin.
All of the old bedding is then scooped over atop the new bedding. Once this is completed, new prepared bedding material, again with food added to it, is put in its place. A strong light placed over the old bedding will help to drive down the worms into the new bedding. The temporary partition is also removed and the old bedding is spread over the entire surface of the new bedding material.
After a few hours, the finished vermicompost can be removed from the bin starting from the top surface. The presence of the strong light will drive the worms down into the new bedding as they are uncovered.
Method Two
Vermicompost ready for harvesting should have a high proportion of worm castings and all of the food waste at least partially broken down.
All of the old bedding is pushed over to one side of the bin and new prepared bedding with food added to it is placed in the vacated side.
Additional food is only placed in the new bedding side to induce the worms to move over there.
After a few weeks, all of the old bedding material (worms included) are removed, placed in a clean container and left to age for a few months. Any remaining food and bedding will be converted by the worms and microorganisms present to a high quality vermicompost with a large proportion of castings.
After removal of the old bedding, the new bedding material is spread out over the entire bottom of the bin.