Harvesting Worm Compost

After you have fed your worms for three to six months, you’ll see some worm compost in the bottom of your bin.  You can harvest what’s there, or wait until your bin is nearly overflowing.  No matter which method you use, some worms will remain in the compost. Worms put in the garden with the compost will not live long, but your main goal is to reserve enough worms to re-start your bin.  You can’t save every worm!  Here are a few methods for separating the worms from the compost.

Method #1:

Most of the uneaten food, bedding and worms will probably be in the top third of your bin.  Remove this material, worms and all, and put it aside to start a new bin. Remove the remaining material from the bin for use as worm compost.  Put the uneaten food, bedding and worms back in the bin, and resume feeding and maintaining your bin.

Method #2:

This method works only in bins over three feet long.  Move the contents of your worm bin to one side, place fresh bedding in the empty space and bury your food wastes there for a few months. Harvest the other side after most of the worms have moved into the new food and bedding. 

Method #3:

Spread a sheet of plastic out under a bright light or in the sun. Dump the contents of the worm bin and build a few cone shaped piles on the sheet. Gently remove the top layer of each pile until you see worms.  To escape the light, the worms will dive deeper into the piles.  After repeating the process every 20 minutes or so for a few hours, you will be left with a wiggling pile of worms. Save your compost and return the worms to their bin and fresh bedding immediately.  Here's a drawing of this method of Worm Separation.

Method #4:

If you are using a manufactured worm bin with stacking trays, try this easy way to Harvest Castings.

Using Your Worm Compost

Using your finished product will help your plants thrive by adding plant growth hormones, beneficial microorganisms, humus and nutrients to the soil.  Vermicompost is lumpy and clay-like when removed from the bin.  Let it sit in a plastic bin or bag away from rain and sun for 1-4 months and it will transform into a fine-grained product!  Sprinkle a layer at the base of indoor or outdoor plants, making sure compost is not piled up against plant stems.  Cover with soil or mulch.  You can also blend worm compost up to 20% into potting mix or garden soil.