Composting in winter is entirely possible, although decomposition will slow down as temperatures drop. As long as you actively manage your compost pile, decomposing will continue even in cold weather. Taking a few extra precautions with your winter composting will ensure your compost is ready to enrich your garden in the spring.
Get Prepared for Winter Composting
If you know you will be composting through the winter, plan ahead for success. Empty any existing compost that's ready for the garden from your compost bins. Since waste decomposes slower in the winter, you'll need to space in your bin. Collect bags of dry leaves in the fall to add to your compost pile. You can store them in landscape bags or covered garbage cans to have them on hand to layer with your scraps and fresh waste.
Leaves and pine needles are an excellent source of "browns" — the carbon-rich material that helps air circulate in your compost pile and reduces odors from other types of waste. If you can't stock up on leaves in the fall, or you didn't plan ahead, you can also use shredded newspaper, sawdust, or woodchips for the same purpose.
Winter Composting Tips
Once winter sets in, you can continue to layer "greens" — fresh waste scraps from your kitchen or garden — with your brown material in your compost pile. Additionally, the following tips can help you keep your compost pile productive and healthy throughout the winter:
Use enough browns. If you've already cleaned your yard and don't have access to enough brown material, it can be tempting to just add fresh kitchen waste to your compost throughout the winter. But if you don't add enough browns, you'll end up with a smelly, sticky mess come spring — not the fresh, loamy soil you want.
In situations where you can't add any browns over the winter, you can continue to add greens to your compost pile and let it sit. Once the weather warms up, you can add browns and turn the pile to aerate it. Your compost will basically remain dormant through the winter with this method, but it may be the best option in some cases.
Protect your compost pile from the cold. Insulating your compost by covering it or building a windbreak. You can use extra leaves to provide insulation. Another option is to cover your compost with hay bales or landscape bags filled with leaves or straw. You can also use a tarp to create a windbreak. Your compost pile may freeze on the outside, but inside, it will remain hot enough to stay active.
Keep a smaller compost bin for kitchen scraps. Using a smaller bin to collect scraps will prevent you from having to access your compost pile as frequently. Start with a plastic tub or garbage can that you have drilled drainage holes in and can cover. Alternate layers of fresh kitchen waste with the leaves or other brown matter you've collected to control odors.
This is essentially just a smaller compost bin that you can store in the garage or out of the way spot in the kitchen. You can either add the contents of this bin to your main compost pile periodically throughout the winter, or you can wait until spring and add it to your compost all at once.
Use smaller scraps. Chop up your green and browns into smaller pieces than you normally would. Reducing the size of your waste provides more surface area for your decomposers to eat. You can chop up your kitchen waste into smaller pieces with a knife, and you can shred your leaves or mulch with a lawnmower or wood chipper.
Consider worm bins. Vermicomposting — composting with worms — can be an ideal solution for winter composting. While worms are naturally attracted to outdoor compost bins, you'll need to add them to indoor compost bins yourself. This doesn't have to be complicated. Just start a small compost bin as you usually would and add a few worms. They'll quickly reproduce in a healthy compost bin, so don't worry about adding a lot.
Fruit flies can be an issue with indoor compost bins, but you can avoid them by freezing scraps for several days before you add them to your compost bin. This will kill any fruit fly larvae and keep them from hatching. To prevent odors, place your waste under a 4-inch layer of newspaper or straw.
Don't worry about turning your compost. If you're wondering how often to turn compost in winter, you can relax. You don't need to turn it at all. Turning your compost pile can actually slow the decomposition rate, since you'll be dispersing the heat that's built up. Instead, wait until spring when the temperature rises to start turning your compost pile.
Starting a New Compost Pile in the Winter
You don't have to have an existing compost pile to compost during the winter. If you're ready to get started creating "garden gold" for next spring's growing season, you can still start a winter compost bin. Start your pile with some rich soil to introduce beneficial microbes that will get the process going. Then gather up some leaves. When it's finished, your compost pile should be 75% leaves to keep the heat in.
Put down 1 foot of leaves, then some soil, and repeat until your bin is full. When you're ready to add kitchen waste, just bury in under the leaves. When spring comes, your compost pile will be smaller. You can start turning it and treating it like a regular compost pile at that point. Your reward will come when you dig into it and find all of the rich compost you've created.