5 Clever Early Winter Composting Tips

If you grow a garden and often eat fresh food at home, no doubt you do a fair share of composting. Maybe you have a nifty multi-bin system, a collection of enclosed composters or even a tumbler, or perhaps you have a big, random heap like mine that gets rebuilt every autumn.

Early winter is a great time to work with your compost regardless of your composting set-up and style. To make the most of this precious garden commodity, consider these five composting details as autumn turns to winter.

1. Prepare New Compost for Winter

Active composting slows to a crawl when temperatures drop to 45°F (7°C). An active heap that contains plenty of nitrogen (usually from animal manure) will generate enough heat to prolong active processes into early winter, but most garden compost piles simply shrink once nights become cold. Before winter arrives to stay, do your best to increase the heap’s size while getting dry materials nicely moist, and then cover it all with a tarp or discarded blanket to help moderate conditions during the winter months. If you’ve already disconnected your hoses to prevent freeze damage, try using a trickle irrigation jug to add moisture to a new heap while daytime temperatures are still decent.

2. Enrich Stressed Soil with Fresh Compost

Several common garden diseases persist from year to year in soil. Fusarium of tomato or basil can arise from soil-borne fungi, leafspot of chard, spinach and beetroot can persist in soil for two years, and random root rots or potato scab are long-term survivors. Amending suspicious beds with fresh, coarse compost floods the soil’s food web with scads of soil microbes, which forces pathogenic strains to fight for survival. When using fresh compost to rehabilitate troubled soil, leave the compost chunky and don ‘t worry about bits of eggshell or broccoli stumps. In addition to suppressing diseases, moving the final stage of decomposition to garden beds is the best way to gain soil organic matter from compost.

3. Store Cured Compost for Winter Planting Projects

Cured compost that has aged for months is black gold that you might find many uses for over the winter months, for example winter sowing of cold-hardy flowers and herbs, repotting or topdressing houseplants, or starting a few early seeds or microgreens. Unlike compost used to combat diseases, compost used for growing seedlings should be well aged. In early work done at Woods End Lab, compost that had cooked and cured for eight months was best for seed germination and seedling growth.

There are advantages to using opaque plastic containers to store compost. They can be kept outdoors in a protected place, and admit enough light to trigger the germination of weed seeds, which can be killed with a vigorous shake of the containers. To radically reduce the number of viable weed seeds in otherwise excellent compost, bring a container indoors, place it in a well-lit place, and give it a good shake every few days for two weeks. Countless emerging weed seedlings will perish.

4. Composting Kitchen Waste in Winter

When ice, snow and mud make the trek to your compost hazardous, start collecting your veggie trimmings, coffee and tea detritus, banana peels and the like in an animal-proof container outside, close to your kitchen door. A garbage can with a lid that can be secured with a bungee cord works well, or you might use an old cooler with a heavy brick or other weight on top. Put dry leaves, paper, dead plants and other organic matter collected in small amounts in there, too, but don’t worry about mixing. The whole shebang will freeze and thaw into a multicoloured mess that you can layer it into an outdoor heap in spring, or as weather permits during the winter months. Note here that a cylindrical container with a well-secured lid, whether metal or plastic, can be rolled to where it needs to go before being unloaded, which mixes the materials and reduces heavy lifting.

If you generate only small amounts of kitchen waste, collect it in the freezer in yogurt tubs, milk cartons or other leak-proof containers until your compost becomes more accessible.

5. Let Winter Have its Way

Repeated freezing and thawing breaks down tough cell walls in compostable materials, making them faster to rot when favourable temperatures return. A deep blanket of snow helps insulate the heap from extreme cold and provides igloo-like housing for little creatures that snuggle up in sheltered spots.

In climates that get lots of cold rain but little snow, the next best thing is to tuck in compost with a cover such as a tarp or old blanket, topped with a layer of leaves. With luck, the compost will keep cooking all winter.

Barbara Pleasant is the coauthor of The Complete Compost Gardening Guide (Storey Publishing).