Friday, July 18, 2008

Common Compost Problems

Here are some common composting problems and how to solve them. Don't worry - you can't do any permanent damage to your compost!

Pile Won't Heat Up

Once your compost reaches maturity, it won't heat up very much between turnings. But if you've just made a new batch and it doesn't heat up after a few days, there could be a few reasons.

You may have used too much brown material - in this case, add more greens like fresh grass clippings, used coffee grounds, or composted chicken or steer manure.

If your pile is too dry, add enough water as your turn it so it's as damp as a wrung-out sponge.

If your pile is too small, it won't have the critical mass needed to retain heat. Make your batches in one of the 3'x3'x3' wooden bins at Interbay.

Heat loss will be faster in the winter so you should cover your batch with several layers of burlap. The wooden sides on most bins at Interbay also help insulate your compost.

Larger Items Don't Break Down

Larger sticks and branches take a very long time to break down. Sometimes sticks interfere with your ability to turn the pile easily. If you can, use pruning shears or long-handled loppers to cut sticks into small sections. Otherwise, exclude large woody items from your mix.


Not all bugs in your compost are bad. Some bugs help break down large plant material so smaller critters can help with the decay process. Pillbugs (also known as roly polies) and sowbugs look like tiny armadillos and help chew up rotting material. Don't kill them. (Here's some trivia: The difference between sowbugs and pillbugs is that pillbugs roll up when frightened, but sowbugs can't roll up.)

Any big fat white grubs you might find in your compost are probably beneficial and should not be killed.

Fruit flies are attracted to, and breed in, exposed food scraps or fruit. Cover any food scraps or fruit with a layer of dirt or finished compost, or dig them deeper into pile so the flies can't reach them. Don't just throw them on top.

Though ants in your pile don't necessarily help or hurt the decomposition process, they probably signal that your pile is too dry. Add water to your pile as you turn it. The ants should be gone the next time you're ready to turn.

Slugs just love the moist, warm environment of a fresh compost pile. I often find them sticking to the burlap covering as I remove it to turn a batch. Pick out any slugs or put the burlap on the ground and squish the slugs.

Plants Sprouting

If you have rootstock or stems that seem to be sprouting in your pile, be sure to chop them to 3" sections or shorter. I have this problem mostly with mint roots. A hot pile should kill most rootstock.

If seeds are sprouting in your compost, be sure your pile has enough green material and moisture to heat up and kill seeds. Seeds usually sprout in slow, cold compost piles that take a long time to break down. Turn any seedlings under before they can set seed.

The Pile Smells Bad

There are a couple of reasons why your pile might stink. If it smells like ammonia or urine, you've got too much green material. (You're also losing valuable nitrogen!) This usually happens when you've added too many grass clippings. Add more brown material like fall leaves as you turn your pile.

If your compost smells like rotten eggs, then there are anaerobic bacteria in action producing hydrogen sulfide. Your pile needs more oxygen, and potentially less water. Turn your pile to introduce oxygen, and don't add any more water. Be sure to cover your bin with piece of plywood to prevent rain from soaking your compost.

Animal Pests

Bury food scraps or fruit under dirt or more compost to keep raccoons, rats and mice away. Covering your bin will also keep larger animals out. Rodents like to bed down in warm compost. Catch any rats or mice you can and drop them into a bucket of water to drown them. Don't set a mouse or rat free: they will multiply to dozens in a few months!

More Reading

Cures for Common Compost Questions at Organic Style

Composter Problems at Quinte Waste Solutions

Compost Problems at REAPS

Guide To Home Composting by Ann Costa at GAIAM

Backyard Composting Problems and Solutions from Washington County, Minnesota

Large C Shaped Grubs In Compost Pile at GardenWeb

Copyright © 2003 Brian Ballard. All rights reserved.

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