If your compost pile is smaller than four cubic feet, it can freeze during winter. Freezing will make compost piles inactive, but is not harmful to the long-term condition of the pile. Larger piles will not freeze but should not be turned during winter. Because there is less yard waste than food waste going into compost piles during winter, it is important to maintain the correct carbon to nitrogen ratio. Turning the pile might release too much heat.
The size and placement of your compost pile affect the likelihood that it will freeze in cold temperatures. A sunny spot and insulation (e.g., straw) are the keys to keeping a backyard compost pile functioning in winter. Get step-by-step instructions for building an insulated bin for composting during winter months.