JoAnne Skelly: Cold weather composting — don’t give up!

I’m watching leaves fall. What does one do with all these leaves? I mentioned in a previous article, some can be used as mulch around trees and shrubs. Others can be shredded with the lawnmower and added to a compost pile. However, winter composting presents a few challenges, primarily due to the cold temperatures. But you can still compost.

We compost organic waste such as kitchen scraps or plant materials in order to break the waste down into humus, a form of partially decayed organic matter that makes nutrients readily available to plants. The decomposition process is caused by bacteria, fungi, worms and other soil organisms feeding on the materials put in the compost pile or bin. These important critters require nitrogen (kitchen scraps and/or green plant waste), carbon (dry autumn leaves, straw, sawdust, etc.), oxygen, moisture and heat (from the sun and the heat put out by the decay activity) for the overall breakdown process to occur.

Fall and winter cold days slow down the decomposition process. The lower temperatures also slow down the organisms in the pile eating all the materials. Once the leaf drop is over, then there is little carbon-based material to add to the pile. Yet, you will still have kitchen scraps and coffee grounds to add as a nitrogen source. In Northern Nevada, we are lucky to have quite a few sunny days to help maintain or reheat a compost pile, if it is located in a sunny spot in the yard.

To winterize existing compost piles, collect all the leaves you can. These will insulate the outside of the pile and maintain some heat in the center of the pile. If you don’t have many leaves, straw works as a replacement. Loosen up the inside of the pile with kitchen scraps/green waste and a small amount of chopped leaves to allow good air flow. Leave a hole in the leaf cover at the top of the pile to pour in future kitchen scraps. When you add the scraps, cover them with about two inches of leaves or straw in the hole. Moisten the pile and cover it with a tarp or burlap. This will help hold in some heat. Building a wind block of straw bales around the compost pile will help keep heat in, too.

Once there’s a spring thaw, turn and water the compost pile.

For detailed information on winter composting, go to http://kenosharacinerecycles.org/news/composting-through-winter, University of Wisconsin Extension.

JoAnne Skelly is associate professor and Extension educator, Emerita at University of Nevada Cooperative Extension. She can be reached at skellyj@unce.unr.edu.