It’s the almost romantic ideal of cold weather composting: steam rises from the well-tended compost pile in the dead of winter, organic wastes in the pile continuing to decompose even as cold temperatures reign outside. Experienced composters with acreage to spare can make this happen every winter. But those of us who live on a little less urban space will likely have to make some adjustments for cold weather composting.
The main reason is temperature. You have to maintain a temperature well above 100 degrees in the compost pile or bin to keep decomposition ongoing. A properly tended, dark-colored compost bin or tumbler in a sunny location can achieve that internal temperature on sunny winter days. The problem is maintaining that heat as temperatures dip after sunset. And there’s the problem of odor: Organic wastes will more slowly decompose, and that can be smelly.
But while you might not be able to achieve high-speed compost cookery this winter, don’t give up. A backyard compost bin or tumbler can still keep decomposition going – more slowly than in the spring and summer – and you can help it out with some extra prep time. We’ve heard of home composters first freezing compostable kitchen wastes in heavy-duty plastic bags, then allowing it to thaw and adding the mix into the composter. The freezing/thawing hastens decomposition by destroying some of the cell structure. We’ve also seen recommendations for chopping up your compostables with a blender before adding them to the composter or compost pile. If we did this, we’d be sure to add at least some of the blender rinse water into the composter; composters still need plenty of moisture in the winter to keep things decomposing
Another option is to give your compost tumbler a break for the coldest month or two, stockpiling your kitchen wastes. Use a heavy-duty garbage barrel or other container that is pest-proof. Some holes drilled into the lid will help reduce odor, as will adding some layers of shredded leaves or sawdust, to help soak up moisture. Just don’t forget it’s there; if things do heat up enough to start decomposition, you’ll want to get your tumbler back into composting action. Plastic containers with handles that are easy to carry can also help you transport other raw materials for composting, as well as finished compost for your yard and garden beds.
The best cold-weather composting option, we think, is an indoor worm bin. A well-tended worm bin will have minimal odor, and the red wiggler worms that specialize in composting will gladly gobble up your kitchen scraps. We’ve even heard of cooperative composting, where several worm bins are kept in someone’s basement and the worm castings shared among those providing the food.
There’s another thing: don’t be afraid to give yourself a break from composting this winter, as many areas are starting to collect food waste for composting. Carry your wastes to that location in your compost containers and do your part to keep down municipal waste. With municipal kitchen and food wastes totaling some 37 million tons annually, according to the U.S. EPA, we all need to do everything we can to turn organic matter into beneficial compost.