Tips for Composting in the Winter

Composting transforms yard and kitchen waste into nutrient-rich soil. However, especially in the Northeast, winter can slow down a compost pile. If a pile freezes, the microbes slow their work of decomposing until it thaws. Here are a few tips to make sure your compost pile keeps on running through the most wonderful time of the year:

Gather leaves

The two key ingredients for successful compost are nitrogen-rich greens (such as vegetative food scraps and grass) and carbon-rich browns (such as leaves or strips of newspaper). The microbes making the compost need both carbon and nitrogen to thrive. Leaves are in short supply in most seasons except for fall. So, when you rake up your leaves, set some aside for use in your compost throughout the year.

According to Ann McGovern, consumer waste reduction coordinator at the Massachusetts Department of Environmental Protection (MassDEP), leaves can be stored long-term if they are kept dry, either in a plastic bag or in a barrel in a sheltered area. Without the presence of moisture, the leaves won’t decompose, and they will last throughout the winter, spring, and summer.

If you want to compost the leaves by themselves, first rake them into a pile and dampen them. Then throw some soil (from the outdoors, not store-bought) onto the pile and cover the pile with a tarp with holes cut into it. The soil contains microbes that will devour the leaves, creating good compost in a few months. You can also use leaves as mulch, where they will eventually compost in place (easiest method of all!).

Get creative with what you put in

During the winter, when there aren’t any leaves, you may need to get creative to find some browns to put into the bin to make healthy compost. As a substitute for leaves, the easiest replacement to find during the winter is newspaper or other paper waste, such as paper towels, napkins, and paper bags. Make sure you tear the paper into strips or pieces, and keep it damp. (See the DEP handout “Composting Is Easy” for more information about what can and can’t go into a compost bin.)

Bigger bins are better

The easiest and most effective way to stop the pile from freezing is to make the pile as large as possible. A bigger pile will keep the warm center better insulated from the cold temperatures. Ann recommends a bin with dimensions of 3’ by 3’ by 3’ (27 cubic feet total), and notes that the New Age Compost Bin, available from Boston Building Resources, is close to that size (24 cubic feet). Tumbler bins, which allow the user to aerate the compost by turning a crank, tend not to hold enough to keep from freezing. Ann recommends a bin with a larger capacity, if possible. It’s also advisable to refrain from turning the pile during the winter because turning undermines the insulation.

Get a second bin started

To increase the amount of compost you generate, and also make use of all your food scraps and leaves, Ann recommends setting up a second bin. Keep the older compost in one and add newer materials to the other. That makes harvesting your finished compost from the older bin a piece of cake!

Don’t be deterred by a freeze

Sometimes, no matter what measures you take, the compost will freeze over. But once spring arrives, the pile will thaw and the compost bin will be as lively as it was before. Ann advises adding new material to the top of a frozen pile and covering it with paper or straw. Once the pile thaws, the new material will begin to decompose rapidly, because the freezing and thawing process helps break down its fibers.

Bring the composting inside

Vermicomposting, or composting with worms, is an easy way to compost year-round. Outdoors, earthworms are attracted to compost piles, but inside, you’ll need to set up a worm bin and add worms. Simply add all of the ingredients that you would add to regular compost, making sure to add nitrogen-rich greens, and add some worms. You only need to start off with a few worms, as they will soon reproduce.

Compared to outdoor composting, vermicomposting is fairly small scale. It should still be enough for a household of one to two people, but for larger households, you may want to use two (or more) worm bins. Another consideration is pests: fruit flies can become a problem with indoor compost. To prevent this, Ann advises freezing food scraps for a week before adding them to the worm bin. That will kill any fruit fly larvae that might have been on the fruit scraps. To prevent odors, Ann recommends burying food scraps underneath a 4” layer of straw or paper. The MassDEP website has more information on vermicomposting.

Don’t be afraid to get started

Winter can be a great time to start composting. Carbon-rich leaves are usually still readily available, and, if you shred them and have a large enough bin, you might have finished compost by late spring. Unshredded leaves will take longer to decompose, but will still make great compost. Nature composts on an annual cycle, and you can adopt that time frame by simply keeping the compost pile damp, or you can speed it up by shredding and turning the material. Either method will result in beautiful compost for your yard and garden!

To start a compost pile in the winter, Ann suggests starting the pile with some rich soil, either from a garden or from previous compost. This will introduce decomposers into your compost right from the start. Next, gather two to five bags of leaves. If you can’t get this many from your own yard, go around the neighborhood. Your compost bin should be filled to the top, and at least 75% of the contents should be damp leaves. This will ensure that the pile is well insulated throughout the cold months. After every 12 inches of leaves, add a little bit of soil as well. Then, simply bury all your vegetable and fruit scraps under the leaves for the rest of the year, and let the microbes do the rest. When the weather warms up, your pile will shrink and you will be able to find finished compost by digging into it. As time goes on, the more composted it will become. During the growing season, use your beautiful compost every time you plant, or spread it around your existing plantings. By next fall, your bin will be nearly empty and ready to fill with a new batch of fallen leaves!

—Daniel Carr

Other Resources

Home Composting Tips from MassDEP

Video: How to Set Up the New Age Composter from MassDEP

Photos of School Composting from MassDEP’s Green Team Program

How to Keep Your Compost Pile Cooking Even When It’s Cold Outside from Rodale’s Organic Life

Composting through the Winter from the University of Wisconsin Extension