Can we compost in winter? Winter composting may simply involve tossing ingredients on the pile and waiting for temperatures to warm up in spring to complete the decomposition process.
On the other hand, if you maintain a warm temperature in the interior of the pile, you can keep the decomposing microbes happy and somewhat active. With a warm center, the cold exterior temperature of the pile won’t harm them. You still can feed them vegetable waste, coffee grounds and eggshells, but you can also add chicken or rabbit manure, alfalfa pellets (sold as rabbit food) or blood meal to give the pile and the microbes a heat-generating nitrogen boost.
Adding an outside layer of shredded newspaper or straw will provide a layer of protection and the carbon source necessary for continued decomposition. Although we turn compost piles in the summer, it is best to avoid turning the pile in winter to help maintain that interior warmth. With a little moisture, the decomposition process can continue.
Indoor worm composting (vermicomposting) is a viable winter alternative. You can use a dark bin to hold the worms.
One online site recommends a bin 1 foot deep, 2 feet wide by 3 feet long. While you might buy a worm bin, you can also make your own. Find a good size bin with a lid. Drill 8-10 holes in the lid and in the bottom of the bin for ventilation. Set the bin up on blocks for good air circulation, placing a tray underneath it and the blocks to catch any leaks from the bin. Add damp bedding for the worms, such as straw, peat moss, sawdust or shredded newspaper, a few cups of sand or soil and put in about one pound of red worms (not earthworms) that you can order online or at a local nursery.
Depending on the size of your bin, feed the worms up to 1/2 pound of coffee grounds, tea leaves and vegetable scraps each day by burying the ingredients in the bedding. Keep the bin covered and place it where the temperature will remain between 55 to 75 degrees.
In the spring, move the mature compost to one side of the bin and add fresh bedding and more food to the other side for two weeks. The worms will migrate from the old material to the new leaving the old ready for feeding plants.
JoAnne Skelly is Associate Professor & Extension Educator, Emerita at University of Nevada Cooperative Extension. She can be reached at firstname.lastname@example.org.