When you hear the words winter composting, your first thought might be, “WHY?” Here are just a few reasons for keeping an outdoor compost bin active through the cold months:
• Helpful if you need (or simply want) to deal with large quantities of waste materials – more than can be handled by a typical indoor home-based system.
• It can be a really fun challenge, and a great way to master your composting skills in general.
• Good way to get some attention and educate others about composting (winter composting is a great conversation piece, too).
• Depending on the techniques used, it can actually provide a supplemental heat source for a winter greenhouse (requires larger composting mass than described below).
• You won’t likely need to worry about the system drying out or overheating (as can happen in the summer).
Now, you’re probably thinking, “HOW?” These tips from renowned Canadian blogger “The Compost Guy” can help.
• A good heat source is necessary to keep your system microbially active. This requires the presence of an external heat source or enough material (‘critical mass’) with a well balanced Carbon to Nitrogen ratio (somewhere between 20:1 and 40:1 works best) to support microbial heating. The critical mass for thermophilic composting is generally in the range of 1 cubic yard – so use a system that has a volume of at least that much (the colder your region, the bigger you’ll want to make your system).
• You’ll need some insulation unless you are creating winter composting heaps significantly larger than 1 cubic yard. An excellent low-tech approach: stack up straw bales around the outside of your bin. An excellent winter system could be as simple as stacked straw bales to create walls filled with your balanced mixture of waste materials.
• To create an insulation system, line the inside of your bin with multiple layers of corrugated cardboard, then build an outer wall around the bin, thereby creating a space you can stuff full of insulation (I use second-hand home insulation). Add some additional layers of cardboard between the outer wall and the insulation layer, and voila. In areas where heavy snowfall occurs, snow can be used for supplemental insulation; just build up big heaps of snow adjacent to 3 of the 4 faces of your bin. Another great naturally occurring source of insulation is the earth itself. Digging a compost pit in the ground into the side of a hill can be an easy (and effective) strategy. It will also help to maintain a thick layer of bedding over the top of your composting mass. Loose straw and fall leaves are very well suited for this task, but there are plenty of other possibilities as well.
• Continually add fresh waste materials to keep your system fueled. Try keeping a bucket (or larger container) for your kitchen scraps. You may even want to seek out external waste sources to ensure you have enough. Local coffee shops (for coffee grounds), grocery stores (for waste produce) or stables (for manure) are just a few possibilities.
For more information on winter composting, visit www.compostguy.com/winter-composting/