Northern Alberta Institute of Technology

How to compost in winter

Reduce your organic waste year-round

The ground is frozen, the garden is dormant and most of us don’t fancy trudging outside to chuck our potato peels.

But ask Jocelyn Crocker why you should use a compost pile in winter and she offers a quick response: “Why wouldn’t you compost in winter? It’s way less effort – and there’s less risk of smells – than composting in summer,” says the NAIT Physics chair and community advocate for waste reduction through Edmonton’s Master Composter Recycler program.

There are benefits to letting all those onion skins, apple cores and carrot shavings break down year round. You divert waste that might be sent to landfill and you create health food for your plants. “Food scraps make up almost a quarter of residential garbage during the summer and 35 per cent during winter. It’s kind of magical turning waste into gold,” says Crocker, who adds that since she started composting, her household has reduced their number of garbage bags from two or three per week to one each week.

Start winter composting with her tips and techniques.

winter composting binsDouble up: Crocker has two backyard bins – one for use from June to October and the other for use from November to May. This allows her to compost twice a year.

“I let the winter bin compost all summer long,” she says. By autumn you can harvest soil that was the previous winter’s compost. But take note: if you can identify a full piece of vegetable, it’s not yet ready. Wait a bit longer.

Location, location location: Put your  bins close to the house. “I keep mine near the garage door, so I can access it easily,” says Crocker. Make sure they’re in the sun but out of the wind, so the pile doesn’t cool down too much. The inside layers of most bins are warmer than the outside temperature.

Cheaters sometimes prosper: Crocker is a self-described lazy composter: “I don’t chop the food up much – you can see whole banana peels and hot dog buns in my compost,” she says. Though the waste in the bin should be “fluffed” or turned every 10 days or so in the warmer months before winter, she manages well by doing it once a month.

winter composting shovelWork in layers: “In the winter, I throw in some leaves and snow every couple of layers. I get lovely compost at the end!” Crocker says. She advises squirrelling away bags of dried leaves in the fall and sprinkling them over the food scraps.

Sniff around: Crocker says that if you’re composting properly, with the right kinds of waste, it shouldn’t smell. A bin with too many “greens” can cause a stink. “If the bin smells of rain, it means the micro-organisms have the right balance of stuff to work on.”

What you should – and shouldn’t – compost: All fruit and veg can be tossed into the bin but avoid adding meat, dairy and fats.

“Meat carries bacteria that can be harmful,” Crocker explains. “To kill that bacteria, the heap has to be at a high heat for a sustained period of time.” (Don’t add pet waste, either, as it can have E. coli.) Bonus: you won’t have coyotes sniffing around for pork chop bones.

Keep out unwanted tenants: Rodents seeking warmth in the fall may infiltrate your piles, so saturate them with water during autumn cleanup to deter them from setting up house.

winter composting, deterring verminWatch and wait for results: “In winter, the compost doesn’t work continuously,” Crocker says, “but as it warms up your pile breaks down.”

A freeze-thaw cycle, she notes, helps decompose the cell walls of fruits and vegetables. “An easy measure of [success] is the volume of the pile. Adding food scraps makes the volume bigger but as it breaks down the volume gets smaller.”

Wait, reap, repeat: Leave your winter waste to simmer in the summer heat and at the end of the next season you’ll have garden gold.


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