Green Calgary encourages you to continue composting throughout the year, despite winter winds, dropping temperatures and snow. Although the decomposition process usually slows down in cooler weather, compost piles will keep working all year long. Residents of your pile, like bacteria, molds, mites and actinomycetes can survive the cold. However, to prolong their active life over the winter, they will need warmth, food, air, and moisture. Follow the tips in this fact sheet to optimize your composting in winter months and welcome spring with a productive, healthy compost pile.
Late fall preparations
Collect bags of dry leaves from your lawn and your neighbors. Stockpile excess dry leaves in large plastic garbage bags or covered garbage cans for use throughout the year. Harvest finished compost from your pile to make room for your winter additions. Since the decomposition process is slower in the winter, you may need the extra room. Use the finished compost in your garden or store it in a dry place for the spring.
Over the course of the winter
1. Continue layering "browns" and "greens"
Adding a lot of compostable material to your pile will shield the critters responsible for decomposition from the elements. Garden waste, spent perennials, sod, and - of course - the ubiquitous fall leaves are good, abundant choices in autumn. It is always best to layer greens (kitchen scraps, fresh garden waste) with browns (dead leaves, straw, newspaper). This ensures the right ratio of carbon to nitrogen, helps aerate and provides adequate drainage in the pile… all of which contributes to next spring's harvest of "black gold." Turning the pile in the winter is not necessary, since it may result in a loss of heat from the middle of the pile.
2. Insulate your bin or build a wind break
Insulating your bin will protect it from the harsh winter winds and cold. While the outside of you bin may freeze, the inside can still "cook." If you find yourself with an overabundance of leaves, pile them on! As you produce greens (kitchen scraps) over the winter, tuck them in under the insulating layer. You can provide extra insulation by surrounding your bin with black bags of leaves or straw/hay bales. Or try creating a windbreak with a tarp.
3. Maintain a "pre-compost" bucket
To reduce your cold winter trips to your bin, start a pre-compost bucket. You can use an empty bucket or trashcan in which you place your kitchen scraps. However, be sure to layer them with adequate browns to prevent smells. Add these materials to your outdoor bin whenever convenient or before your pre-compost bin gets too heavy.
4. Reduce particle size of browns and greens
The cold weather slows down the compost process. Smaller particle sizes of greens and browns provide more surface area to speed decomposition. Set up a cutting board for compost and chop up your food scraps before putting them in the bin. Leaves can be shredded with a lawn mower or trimmer.
Early spring maintenance
If your pile should freeze over the winter, it will return to active duty once thawed. Once it does, you will be happy that you took the time to layer your greens with browns. One common mistake is to pile all the winter's kitchen scraps onto your pile without layering or mixing in browns. All-greens piles are almost always stinky! If your pile is excessively wet due to the spring thaw, turn it and add more browns to soak up this moisture. Thanks to Cornell Cooperative Extension and Thompkins County Solid Waste Management Division for letting us share this article with our readers.