In The Garden — Screening And Harvesting Your Vermicompost
By AMY MUNCY
Master Gardener
WARSAW — You may need to screen your vermicompost, especially if you’ve used rough stuff (sticks etc.) in the bedding that takes time to break down. A round gardener’s sieve with a 3/16 inch mesh will work best. Try to find one with stainless steel mesh, it’ll do the job much faster and the worm castings won’t stick to the mesh. Also it won’t rust. Yet other kinds of screens will do fine.
This is also a good way of separating the worms from finished vermicompost, though capsules and hatchlings are lost. If you want to keep these for future generations, try the following so as to not remove too many.
This method is called “light” separation. Dump the finished material from the box onto a big piece of plastic on the floor or a table under a 100W light, or outside in the sun. Form it into eight or nine mounds. Worms are sensitive to light and immediately burrow beneath the surface. Wait a few minutes. Meanwhile put fresh bedding such as damp cardboard or moist shredded paper in the box.
A hand brush and dustpan are great for this part. Lightly brush the top off each mound until you see worms, then wait for them to burrow deeper and repeat. Eventually you’re left with a squirming mass of worms all trying to get under each other to avoid the light. Quickly put them in the new bedding in the box with a fresh supply of feed.
This leaves you with a rich harvest of worm castings. The worms in the bin will soon replace any capsules (eggs) that were lost. Store the castings for a couple weeks before using them in the garden. I would think kids would love this. if you have any children around, you may be able to talk them into doing this for you.
The method called “sideways” separation is as follows. Gently move all the material in the box to one side and fill the other side with fresh bedding. Put your kitchen scraps and feed in the fresh bedding side and don’t feed the old side at all. In a week or two the worms will migrate from the finished vermicompost into the fresh bedding. In the meantime the capsules will hatch and most of the hatchlings will move across. So you won’t lose them, which is an advantage over the dump-and-brush method.
The method called “vertical” separation is basically making a sandwich with mesh screen between layers, the lower layer can be harvested after the food runs out. The worms all move to the top layer which has the screen overlapping the edges of the container. Grab the “overlapped” screen and remove top layer and dump the bottom layer in the garden. Replace the top layer in the bottom of bin and repeat with more screen and fresh bedding.
The “no hassle” method will give you lots of trouble-free castings, but no extra worms. Go on feeding kitchen scraps to a box for up to four months. Then start a second box. In it, put fresh bedding and a good supply of worms from the first box. Leave the first box alone until the second box is full. By this time the first box will contain a very high proportion of fine castings and very few worms.
To make sure there are enough worms for both boxes, you can prepare the second box about a month earlier, adding some worms to it every time you add feed to the first box.
Next time there will be more information to share about vermicomposting. Such as how to harvest the soil and tea uses. So stay posted.
Amy Muncy was born in Wabash County and lived there for close to 40 years. Muncy grew up in the country, has always enjoyed gardening and mowing the lawn. She has been gardening since a small girl. She moved to Kosciusko County in 2000. She is a master gardener intern at this point, but will be a full master gardener before long.