How can you keep compost cooking when it's COLD out?
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Q. Mike: I use your formula of four parts shredded leaves to one part 'green' nitrogen-rich stuff to make compost. But those leaves arrive in the Fall, just as our temperatures start dropping. Isn't it difficult to reach 'hot compost' temperatures over the winter? Do you recommend mixing the compost to keep it hot? Or would this cool down the reaction? And my compost bin is wire mesh; does it let too much cold air in?
- ---Dave; just west of Allentown PA
- ---Jim in Theresa, Wisconsin
- ---Frank in Philadelphia
- ---Rick in the western suburbs of Philadelphia
In my actual composters—black plastic and cedar wood bins, more wire cages, tumblers and spinners (yes, I really do have just about every type)—I mix the rest of my shredded leaves with the dead plants of summer and 'green' kitchen waste (which includes coffee grounds, tea bags, eggshells and other non-emerald colored items). Note: This works best with regular, flat-to-the-ground composters; my drums and spinners get filled last, if at all; as they are very difficult to turn when the contents become one giant frozen glop.
Then as winter progresses, our daily scraps go out to a galvanized 'slop bucket'. (Mostly because I don't want to walk all the way over to my compost corral every day; it's on the far side of the house.) When that bucket is full (I'm guessing it holds around four gallons), I pray for warm weather because otherwise, that frozen mass needs to come into the house to warm up for a day. (You'll find this listed in my wife's "these are a few of my favorite things" file.) Then I mix the contents—always with four parts shredded leaves—into one of the piles.
That's what I recommend our Wisconsin listener try. While I don't think being put in the freezer has any negative effect on kitchen waste (in fact, it probably preserves the nutrients), I wouldn't waste my precious freezer space (and energy!) on garbage. And if it's already out in the piles, it can begin composting on the first nice day without having to be defrosted first.
I don't do no turning, and there's always a good amount of finished compost at the bottom of my piles in the Spring. I use that right away and make a really big pile out of the half-finished stuff, which cooks like crazy and is generally ready VERY soon after.
In short, I don't sweat it. Yes, my winter compost is 'cold'; that is, it took a while to change into rich black gold, and is therefore going to be less effective at fighting disease. It's still darn good plant food and a great soil improver. And my 'in-season' compost is 'hot' (especially what we get from that big pile of half-cooked leftovers!), and I try and reserve that hot stuff for compost tea making and disease fighting. But when weather, circumstance, and/or a sudden pulling of my car to the right hand side intervene, I don't sweat that part either. (You noticing a pattern here?)
But I should pretend to answer this question, so I called my old friends Eliot Coleman and Barbara Damarosh, who sell wonderful organic produce YEAR ROUND from their "Four Season Farm" up in Harbor side, Maine, where it is technically warm maybe three weeks of the year. Eliot wrote an article describing their winter composting system that appeared in a 1992 issue of ORGANIC GARDENING magazine (back when I was Editor-in-Chief), and was kind enough to delay doing something important with leeks to give me an update recently.
Yes, he told me; he still does it. He pays local farmers the cost of baling up any spoiled hay and uses the bales to create an insulated compost pile. "Twenty bales laid like bricks, two bales high, will create a four foot high wall that's roughly five by five inside. I lay a big piece of plywood on top to keep snow out," he explains, "and lift it up to add materials over the winter."
Back when the article was written, they used straw, recalls Barbara, who explains that they switched to hay because they had to pay full price and travel for the straw, whereby the hay is almost free and very close to the farm. (I'll add that you can often find bales of straw or hay for free or cheap when Halloween corn mazes and hayrides and such are torn down in the fall.)
So those bales make hot compost in the dead of winter? "Heck, no," laughs Eliot, who explains that "nothing happens when its below 40 degrees out! But the insulation IS a big help; a lot of the bottom is done when we tear it apart in the Spring. Then we use the half-rotted bales as our brown material that summer." He adds that if you really need to cook compost over the winter, try using a hot source of nitrogen, like horse manure, poultry manure or coffee grounds in an insulated pile. Super-hot crab, shrimp or lobster waste would work even better; but you'd have local cats and raccoons turning your pile for you.
Also back in '92, an ORGANIC GARDENING reader in West Buxton, Maine did detail a true cold-weather composting system. Judy wrote that she mixed rabbit manure, alfalfa hay and kitchen waste into a 3 x 3 cold frame in her garden, kept the snow brushed off the top of the glass, and despite temps that often dropped below zero, says the material was always finished compost by Spring.
So be like Judy! or just make lots of piles, mix in your scraps as they occur and let Nature happen. Or put a worm bin under your sink, which WILL make super-premium compost out of those scraps over winter—while you stay warm!