We often think of composting as a warm-weather endeavor, but there’s no reason to stop making it just because there’s frost, or even snow, on the pumpkin. In fact, you can keep compost cooking – albeit more slowly – throughout the winter, as long as you take one important step: insulating the pile to keep the center hot.
The idea with a winter compost pile is to not expect the pile to get as hot as it would in warmer weather. The outside of the pile will be about the same temperature as the air. It’s the temp inside that counts. Keeping the center of the pile hot by insulating it and not turning it allows the microorganisms to multiply and do their jobs breaking down the compost materials.
First, before starting your winter compost pile, use up any compost left in your bins or piles by putting it in your vegetable or flower garden. Start the winter pile (or piles, if you have the space) from scratch. Locate the new pile where sunlight will hit it, if possible.
Have plenty of “browns” – the carbon-containing materials that are the “dry” part of the pile. These include dead leaves, small twigs, hay or straw, dried grass clippings, pine needles, or newspaper. Browns make up the greater part of any compost pile, and help keep the pile from smelling. Two-thirds of the pile should be browns.
One-third should be “greens” – succulent, wet material, such as vegetable and fruit peelings, spoiled vegetables, green grass clippings, green plant material such as leaves and stems, or fresh manure (from herbivores only). These provide nitrogen.
Unlike in summer, a winter pile might not get hot enough to kill diseases, so don’t add any vegetation from the garden that had disease problems. And, of course, never add meat or dairy to a compost pile.
Smaller pieces, whether brown or green, decompose faster, so chop or shred materials before adding to the pile. Build the pile in layers of dry and wet materials, and continue layering throughout the winter.
Keep the bin or pile insulated by surrounding it with hay bales, or plastic bags filled with leaves. You can also cover the pile with a tarp. The idea is to hold as much heat in the center of the pile as possible. Don’t turn the pile as you would in the summer. Just let it sit.
Check periodically over the winter to be sure it hasn’t dried out. It shouldn’t be soaking wet, but as moist as a wrung out sponge. If it’s wet, add more dry brown material. Don’t worry if the pile freezes, it will heat up again once it thaws.
In early spring, once daytime temperatures are consistently above freezing, stop adding materials so everything can start to really cook. Check at the bottom of the pile first for finished compost. Shovel that out, then turn the pile and mix the brown and green ingredients together. This will speed decomposition, and should give you rich, earthy compost by early summer, by which time you’ll have started another compost pile (or two)!