Too many worms? Worms are balling up!
Worms ball up when they’re uncomfortable, most often because the bedding is too acidic, unevenly wet or too warm, or the bin is new and crowded. Stop feeding for a few days, fix the moisture, add crushed eggshells, loosen the bedding and give a big batch of worms more space. New worms usually settle within a few weeks.
Hi, I recently started a worm bin. The farm I ordered from mixed up my order a few times, so to make up for it they sent me 3 lb of worms instead of 1. The worms have only been in the bin for about a week. I’ve given them a few handfuls of food and coir/paper bedding. I added some water when they arrived because the bags were almost like sawdust, super dry, and put extra cardboard and paper on top so it wasn’t too wet.
Today I noticed a huge ball of them on one side and barely any elsewhere. Not sure where to go from here, but I don’t want them to die! Any thoughts would be greatly appreciated.
Hello Brett,
Your setup sounds quite OK, but worms all clinging together is not a good sign. Compost worms often need a few weeks to settle into a new home, but they shouldn’t ball up. It usually means they aren’t comfortable.
The bedding may be too acidic, and they’re huddling together to protect themselves. Another possibility: worms multiply according to the surface area of their bin. If the bin is too small for the number of worms, some (mostly the big mature ones) may try to leave at night to find a new home.
In most cases these problems disappear after the bin has been running for several weeks. If things don’t improve, it can be worth starting the bin again from scratch.
The full answer
Over nearly 30 years of worm farming, first in South Africa and then in Germany, I’ve seen plenty of worm balls. They’re a warning sign, but easy to fix if you act early.
Why do compost worms ball up?
Worms ball up to protect themselves when something in the bedding is wrong. Clumping together keeps them moist and shields them. Common triggers are bedding that is too acidic, too wet in one spot and too dry in another, too warm, or too fresh (new coir or paper that hasn’t settled yet). Worms also gather in a ball around a patch of food or moisture they like, and that kind of clump breaks up again when the food is gone.
What should I do when my worms are balling?
- Stop feeding for a few days. Take out any food that smells sour or rotten.
- Check the moisture. Squeeze a handful of bedding: one or two drops is right. Add dry shredded cardboard to wet spots and water to dry spots.
- Balance the pH. Dust a spoonful of finely crushed eggshells or agricultural lime over the bedding.
- Check the temperature. Compost worms cope with 5–29 °C (41–84.2 °F), ideally 15–25 °C (59–77 °F).
- Gently loosen the bedding to let air in, and spread part of the ball over the rest of the bin.
- Leave the lid on and a light on for the first nights. Worms avoid light, so they stay in the bin.
Did 3 lb of worms in a new bin cause the problem?
It can play a part. Rule of thumb: 1 kg / 2.2 lb of worms (about 4,000) eat about 0.5 kg / 1.1 lb of food a day once they’ve settled, and they need a bin with enough surface area. Three pounds of worms in a small new bin is crowded. Either use a bigger bin or split them into two bins. See starting a worm farm for bin size and bedding.
Is it normal for new worms to behave strangely?
Yes. Worms that travelled in a bag need time. In the first one to two weeks they may wander, ball up or try to leave. Give them moist bedding, very little food and peace. It usually settles within a few weeks.
When should I start again from scratch?
If the bin smells sour or rotten, or the worms keep balling or escaping after two or three weeks of the steps above, empty the bin, mix the worms with fresh, moist worm bedding and restart with small feeds. My feeding your worms page shows how much to give.
Still stuck? Describe your bin on the free helpline and I’ll take a look.
Happy worming!
Stephan Kloppert
Nearly 30 years of worm farming in South Africa and Germany
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