Everytime I turn the compost in the bin, once every ten days or so, I notice that almost all worms are in the corners really close together. Lots of them. They are not trying to escape, they just always feed there.

When I put a tray on top they get to the rest, because I've harvested a couple of trays, but I never find them in the middle of the top tray.

When I put the organic material I spread it evenly on the whole surface. I do not add dry grass or something like that, just the kitchen scraps and shells. I have one of these compost bins.

Is this the normal behaviour for worms? Should I be worried?

compost bincenter of top traycorner of top tray

  • 2
    Their movement implies there is something about the environment in the corners that they prefer, or alternatively and probably more likely, in the middle that they are avoiding. The worms are alive so it's not necessarily awful, but they are not totally happy in their home. The question is what about the interior environment is different. I'd look first for either too much or too little water, air, and heat.
    – InColorado
    Feb 5, 2021 at 3:36

1 Answer 1


Your compost bin isnt breathing enough. Dirt will tend to pack more densely in the centre. Worms are avoiding that due to lack of air. Change your container to something with holes in the sides.

In response to comment:

Looking at the picture again, your material seems too wet.

I made a worm system with holes in the very bottom too, using rubber made tubs. I used 3 tubs. The basement tub was intact, and had a couple of bricks in it. The other two tubs had air holes at the top, and drain holes in the bottom. In normal use the empty tub was set inside the bottom tub, and the the active tub in the empty tub. Holes did not line up.

Occasionally a worm would escape through the bottom. But liquid could drain through the bottom.

Once a week, I would lift the active tub up, and dump it into the inactive one, lift out the new active one, set it in the new inactive one, drain the bottom one if needed and put togehter my stack again.

You can also lighten up the mix by recycling the root balls of dead houseplants, or crumpled newspaper.

  • I like that theory. It's a commercial bin with airflow holes just at the top. Maybe the designer got it wrong, or maybe I'm putting too much food inside and so it packs. I'll try to put less food for a while and keep the center free and see what happens. Feb 18, 2021 at 23:30

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