Horrible Odor in My Worm Bin

by Lindsay
(Ontario, Canada)

I started indoor composting about 3 months ago. I use a worm bin and started with a pound of worms. Everything was going really well until about a week ago, when my bin started to smell really bad. I don't think it's a moisture or anaerobic issue, because I add a slurry of fruits/veggies every couple days, and my bin has lots of air holes. Do you have any suggestions?

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Apr 22, 2010
Remedies for a Stinky Worm Bin
by: Compost Junkie Dave

Hi Lindsay,

Thanks for visiting our site, and posting your odor-ific indoor composting question. Please try one of the following suggestions and let us know if the odor goes away...

As you probably already know, a proper functioning worm bin, shouldn't have any odor at all. Chances are high that parts of your bin have gone anaerobic, even though you have lots of air holes.

Suggestion 1 - If your bin seems overly moist, you may want to add some more dry bedding material (not too much though). Try your best to gently mix this new bedding in with the older material. This will help remove excess moisture, and re-introduce oxygen into the bin by creating more air pockets in the bedding.

Suggestion 2 - You may be overfeeding your worms. If so, don't add any new food, or slurry, to the bin for 2-3 weeks. Don't worry, you're worms won't starve. If this happens to be the issue, you'll find that once your worms catch up on the backlog of waste, the odor should disappear.

Suggestion 3 - Sometimes a stinky worm bin can be caused by overly acidic conditions. This is often the case when individuals add a lot of citrus fruit, tomatoes, and/or coffee grounds to their bin. If this is the case, then you'll want to neutralize your bin by adding some calcium. This can be accomplished with powdered calcium carbonate from your drug store (vitamin/supplement aisle); pulverized egg shells, or you can contact me directly to try a free sample of ReCharge, our soon to be released soil remineralizing product.

Please try one, or all, of these suggestions and let us know how it goes.

Happy "Indoor" Composting!


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