How to Compost in the Winter

A trio of wood compost bins outside in the winter snow.

When you envision a compost bin, you probably picture the hot sun beating down on your composter. That’s a fair assessment, since compost piles need to reach a 140-degree minimum temperature in order for decomposition to take place. Although summer days create an ideal environment for compost bins, it is possible to maintain a compost bin throughout the colder winter months. Obviously, it takes a bit of dedication and patience because it will not work as effectively as a summer-heated compost pile. To make your compost bin work for you during the winter, follow the steps below.

Step 1 - Consider the Location

large wooden compost bin

Often during the summer, a compost bin can overheat in all-day direct sunlight, so you may have it located in a slightly cooler part of your yard. For winter, move your composter into an area that receives the maximum amount of sunlight your yard can provide (for instance, this won't be under a tree or canopy). Even during cold weather, sunshine will help heat and breakdown your compost.

Step 2 - Insulate the Compost Bin

Create a cozy cocoon for your compost by insulating your bin. This process will take different forms depending on the type of compost bin you have. For an open pile, you will need to tightly cover it and that may still not offer enough protection in areas with frozen ground. For partially-covered composters, make sure to add a cover. Enclosed composters are best for winter composting since they offer the most protection from the elements.

All compost bins will benefit from stuffing green material such as leaves and straw along the inside of the barrel to insulate the materials in the center. Adding cardboard to the inside of the barrel is another good insulation choice that will easily break down. On the outside of the bin, there are a few choices for insulation. You can place wood slabs around the bin and these will help to keep the cold temperatures from entering the bin while allowing aeration to occur. Hay bales are another low-cost option. Stack the bales up along all sides of the bin as this will keep the warmth inside of the bin. Styrofoam is another option. It will keep the cold out of the bin and heat within. The downfall with Styrofoam is that it won’t let air into the bin as easily as straw or wood and it is not an earth-friendly material.

The compost bin can also be placed in the ground. To do this, dig a hole in the ground big enough to hold the bin and its extra insulation. The ground will conceal the bin from harsh winds and winter elements while holding the heat in. Once the bin is insulated, cover the insulation with a dark tarp or black plastic. The dark color will attract the sun warming the contents. The covering will also add extra protection from the winter elements. Be sure to leave an access so you can continue to add materials to the composter.

Step 3 - Add Compost Activators

adding food to a compost bin

Certain materials stimulate the compost to heat up (and consequently, break down). Popular choices include alfalfa, cottonseed, soybean, and bone and blood meals. Coffee grounds and rabbit manure are also good choices. Continue feeding the bin throughout the winter. The process of decomposition creates heat so scraps and brown material will insulate and heat up the bin. If there are not many scraps in the winter, go to local coffee shops or grocery stores and ask for their waste. Many stores will happily provide old fruit and vegetables or used coffee grounds. Cardboard boxes and newspapers can be torn up and put into the bin to supply the needed amount of brown material and these are given away by many companies. Remember to try to maintain a balance between organic ingredients (food), brown materials (bags and branches), and green products (grass clippings).

Step 4 - Let the Compost Bins Go Dormant

As the temperature becomes colder, decomposition will slow down and sometimes stop even in the most insulated bins. This is OK. Continue feeding the bin and allow the weather to warm. Once temperatures rise, the bin will begin decomposition once again. Remember to stir the contents of your compost bin by spinning or with a pitch fork to incorporate materials together as they decompose.