Do Worms Leave When Compost is Done?

by Doris
(Oakland, CA)

I have a large round plastic compost bin similar to the photo though mine is slightly wider and bigger.

I have lots of worms in the bottom that appeared on their own. Can I assume they're earthworms and not wigglers even though some of them look kind of red to me? I heard earthworms sit near the top and red wigglers slightly deeper. But my worms are all the way on the bottom. I'm guessing they crawled up from the ground and aren't moving farther up because it's too warm. But they're multiplying fast and I see LOTS of worms sometimes clumped together when I pull out compost from the bottom opening.

You are exactly right. Those worms are earthworms but not the red wrigglers and they won't go up into the warmer part of the compost because it's too hot for them.

Question: How do I know when they are ready to use in my garden? Does the fact that the worms are still there mean they are still busy composting and not yet ready?

It could mean they are still busy composting but in this case I think you've created fantastic conditions for earthworms and they are happy hanging out there.

When they're done, where do they go? It is a bottomless bin (technically the plastic bottom has holes) so maybe back into he ground? I would've thought they would work up to the rest of the bin, but it is pretty warm; my compost thermometer reads about 110 degrees F in the middle. I aerate the bin often and keep moist.

They are free to back into the ground your bin is sitting on.

They are unlikely to migrate upward as it is too warm for them. As that upper material breaks down and cools down they will move to it.

Take the compost from the bottom of your bin and use it. The warmer material will sink down and my guess will soon be full of earthworms. I think what you've got going on is great so I'd be reluctant to mess with it.

Also, I have used some of the (semi-ready?) compost on my garden beds. This compost has worms in them. I assume that's a good thing since we want worms in my soil. I see people sift out compost and I never see worms in them.

The trick here is to put your compost on top of the soil. Don't bother digging it in. You already have a herd of ready workers in place to pull the compost gently into the soil.

Sifted compost does look cool but personally I don't sift. Plus if you did that you'd seriously disrupt those valuable worms.

The compost now is dark and moist, though leaves have not yet disintegrated. It's been there for at least 6-8 months. I sometimes put my food scraps through the food processor, and there are no recognizable food items in the bin.

Your compost sounds fantastic. Leaves can take a very long time to fully break down. The worms will drag some of those leaves into the soil. That's their food at the moment I suspect. But if you place the compost on top of the soil and let your worms do the rest you should have no worries.

Wonderful work Doris. Keep on trucking.
Leslie