December 19, 2015

1 - Composting in New Mexico can continue even through the cold of winter.

Yard and Garden December 19, 2015


Does it make any sense to keep putting material from my kitchen in my compost pile in the winter here in New Mexico? It is cold outside and I wonder if the material even decomposes in the winter.


While going outside to "feed" the compost pile in the winter may be a chilling experience for you, our winters, though cold, can be warm enough for compostable materials to continue to decompose. The key to winter composting in New Mexico is to provide a proper ratio of carbon to nitrogen in the compost feed-stock to keep the compost microorganisms busy feeding and generating heat through their metabolism. In extremely cold weather the metabolism of the microorganisms and the type of microorganisms may change, but composting should continue even if at a reduced rate for a time.

Several years ago a friend told of starting a new compost pile in Albuquerque from fallen leaves in January. After shredding and piling the leaves from her trees, she noticed steam rising from the compost pile in less than a week, even though temperatures were dropping to 10 degrees at night. The microorganisms decomposing the leaves were able to start the composting process and to generate enough heat to reveal their presence even under very cold conditions.

Gardeners maintaining a large enough compost pile to self-insulate and hold heat in during the coldest periods will help the composting process to continue. In the coldest parts of New Mexico additional insulation may help. Gardeners can provide this extra insulation by placing straw bales around the compost pile, or at least on the north and east sides of the compost. Our sunny days will help rewarm the south side to keep temperatures high enough for composting organisms to keep working. In regions of New Mexico with significant snow accumulations, the snow can provide insulation. When I lived in Montana I learned that in areas without snow cover the soil could freeze to a depth of 3 feet, but in areas with good snow cover, the ground rarely froze, and never froze to such a depth. The snow can provide the same protection to a compost pile allowing retention of metabolic heat from the microorganisms.

Large receptacles in a kitchen can be used to store kitchen wastes indoors. If these containers have tight lids there should be no problem with odors, even when opening them briefly to add new material. The material in the indoor receptacles will begin composting while indoors and provide metabolically active material to the outdoor compost when taken outdoors. This allows providing a larger quantity of active material to the outdoor compost pile to boost warmth even in the winter. When adding additional kitchen wastes to the outdoor compost pile, gardeners can mix the kitchen wastes with hot water to provide a little boost in temperature if needed.

Additional information about composting in New Mexico can be found at the New Mexico State University College of Agriculture, Consumer and Environmental Sciences web site. Look for information at ACES Publications. You can also contact your local NMSU County Extension Service office for information and help.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email:, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at, or at the Desert Blooms Facebook page.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!