1. Prepare for the slow-down
Composting is a biological process that decomposes organic material under aerobic conditions – meaning oxygen is required for bacteria to break materials down. The only trouble is – cold temperatures often slow or even stop decomposition, as aerobic bacteria often become more sluggish in the winter.
Even when the temperature drops, some microbes responsible for the breakdown of organic matter can remain active in the compost pile, according to the Texas AgriLife Extension Service. Since the digestion process generates heat, the center of your pile may still remain warm and actively composting.
However, the outer (visible) portion of your pile will cool to outdoor temperatures. So, you may notice increased decomposition time in these areas. Don’t worry about it. Once the temperature warms up, microbial activity will resume as normal as long as you maintain a healthy balance in your pile.
2. Build a shelter
Constructing a shelter for your compost pile is the No. 1 way to help keep it active for the entire winter season. Start by building a protective barrier around your pile with cinderblocks, bricks, sand bags or plywood, suggest the University of Illinois Extension. A barrier between your compost pile and the frigid winter air will help keep internal heat from escaping, promoting active decomposition.
Not sure where to get started? Check out these detailed plans for a compost pile shelter from the Greater Vancouver Regional District – which include necessary materials and measurements as well as step-by-step instructions. If your’e feeling extra-ambitious, use metal sheeting or plywood pieces to add a roof overtop.
3. Keep it dry
Compost piles should always be kept moist to ensure proper decomposition. But loads of winter snow and spring rain can actually drench your pile, which will force air out of pore spaces – killing your bacterial buddies. So, try to keep your pile dry and protected during the winter to ensure a healthy balance.
If you haven’t installed a roof over your pile, the best way to keep it dry is to cover with a tarp. Securely fasten the tarp of your choice over your pile using stakes, and keep an eye on it to make sure the wind doesn’t knock it free. In addition to keeping out precipitation, a tarp will also help trap internal heat for a more active pile.
4. Add the right stuff
A balanced compost pile requires carbon-rich (also called brown) materials to give bacteria energy and nitrogen-rich (also called green) materials to help them grow strong and reproduce. While equal quantities of both materials are your best bet during the spring and summer, your pile needs more “brown” matter during the winter season.
Brown materials, which include leaves, tree branches and other yard waste, give microbes the energy to continue decomposition despite chilly temperatures. So, add as much of these materials as you can when temperatures are low.
So, what about food scraps and other “green” materials? Frigid temperatures impede bacteria’s ability to process these materials. So, give them a helping hand by shredding your green materials to particles less than two inches in size, suggests the Texas AgriLife Extension Service. Smaller particles allow your pile to heat uniformly and will insulate it from outdoor temperatures, the organization said.
Compost shredders (like this one from Improvements) are available in stores and online for less than $200. But if you don’t want to shell out the cash for a store-bought shredder, check out this tutorial from Mother Earth News – which will show you how to make your own shredder from a self-propelled rotary lawn mower.
5. Dig a hole and bury it
If you’re wary of loads of non-decomposed waste sitting on top of your pile until spring, take a different approach to composting until temperatures warm up. The Texas AgriLife Extension Service suggests digging a trench in the garden or flowerbed and adding organic waste (like kitchen scraps) little by little, making sure to bury the waste after each addition.
Don’t have a garden at home? Just dig a one-foot hole anywhere in the yard and cover it with a board or bricks until it is full of organic waste. Once your hole is full, bury it with soil, and dig another one to keep composting all winter long.