How to Make Compost in a Cold Climate

For the past three Wisconsin winters we have tried, without much success, to keep an active compost pile. We’ve followed all the standard instructions. We place a thick layer of coarse material (cornstalks and the like) on roughed-up earth, put a couple of inches of cow manure over that, pile the kitchen garbage on, and finish the whole thing off with a thin cover of soil and a sprinkling of water.

The three- to -four-foot mound heats up for a week or so, but then gives in to the cold weather and dies. What are we doing wrong? Is it possible to keep a compost pile alive during the winter?

I wouldn’t say you’re necessarily doing anything wrong, but you need to distinguish between two different approaches to making compost. A hot pile is made up of shredded materials, which are put together all at once and kept warm by turning the mound every four or five days, or whenever the temperature in the pile drops below 100°F. No soil is used in such a mound. Compost from a hot pile is ready to go out to the garden in a few weeks.

It sounds as if what you made is a layered pile. This is the type of compost we make. It takes longer, but is less work than a hot pile. As you described, coarse materials are put at the bottom (the humic acids from the materials on top help the rough stalks and such to break down, and the coarse bottom layer allows air to penetrate the pile). Next, kitchen and garden wastes are added (we don’t use manure, but many folks do). Each layer is watered as it’s put on, and finally, the mound is covered with soil.

This type of compost pile may heat up once and then cool, but as long as it’s kept moist the breakdown activity will continue. Our layered compost takes about four months to decompose. We work on a six-month cycle, making compost in the fall to be ready for spring, and again in the spring for use the following fall. We also turn the piles once, about a month before we need to use the compost, to insure a complete breakdown of the materials.

We’ve found that the best compost is at the center of the pile, while the compost on the outside tends to become dry and not decompose at all. An insulating layer helps prevent that problem by keeping the outer compost damp. Perhaps your pile is losing too much moisture. Try applying a thicker top layer of soil, about three inches, and enclose the mound in a wooden or cinderblock bin to help insulate it (surrounding the pile with hay bales will do the trick, too). Although three feet is the usual minimum size for a compost pile, a five- to six-foot mound is the smallest you should build for successful composting in colder climes.

So make your piles larger, insulate them (and keep the mound moist, if necessary), and if you want them hot, turn them regularly. Otherwise, sit back and let nature do it for you!

John Jeavons and Robin Leler, dedicated researchers and mini-farmers