By Beth Botts [ https://www.chicagotribune.com/lifestyles/home/ct-home-0131-garden-morton-20190124-story.html ]
With snow on the sidewalk and ice on the porch steps, a reasonable person might ask: Do I really have to take the potato peelings out to the compost bin? They wouldn’t break down until spring anyway, would they?
In fact, there’s probably action in your compost pile even in winter, according to Meghan Midgley, soil scientist at the Morton Arboretum in Lisle. The bacteria, fungi, pill bugs, nematodes, earthworms and other forms of life that digest dead plants to produce compost may have slowed down, but they didn’t leave for Florida.
“All the organisms in your compost pile evolved in the soil,” Midgley said. “They’ve survived in the soil through the winter for millions of years.”
The outer, most exposed layers of your compost might look like a frozen wasteland. Microbes can’t digest ice. But the interior is warmer, insulated by the accumulation of fruit and vegetable scraps, dried leaves, grass clippings, weeds, discarded annuals, frost-wilted vegetables, and all the other plant matter you added all season long. Within that insulation, composters are still at work, producing rich, fluffy compost to spread over the roots of trees and other plants or mix into the soil when you start planting.
As the cold seeped in last fall, composting organisms retreated toward the center. Those left at the chilly outer fringes may be dead or just dormant, waiting for a warm spell, Midgley said. The ones farther in may be functioning slowly, but they still function.
Although a small pile will often freeze solid, a large enough pile — at least a cubic yard — nearly always has bacteria at work in the middle. They generate heat, creating an environment warm enough for other organisms to stay active as well. If you dig into the center of a compost pile on a cold day, you may see steam rise.
Compost will stay warmer and more active in a bin that holds in heat and blocks cold winds than in an open pile. Adding insulation can help if you’ve saved some of the leaves that fell from your trees in autumn. Covering your kitchen scraps with a layer of leaves might provide enough protection to allow the composters to go to work on your potatoes.
Many factors affect how much compost is generated over the winter: the size, moisture and composition of the pile, the severity of the weather, how often you add leaves or dump your potato peelings. But the worst that can happen is that composting is delayed until the weather warms up.
Sometime in spring, there will be compost to spread for mulch over the roots of your trees and other plants and to improve your soil with organic matter and microbes.
So what about those potato peelings? Is it worthwhile to brave the icy steps to add them to the compost?
It couldn’t hurt, Midgley said. Kitchen scraps won’t break down as quickly as they would in July. In fact, they may lie frozen until spring. But eventually, the composters will find them.
If you don’t have a compost pile already, this is not the right time to start one, Midgley said. Wait until spring, when there is warmth and moisture. Or wait until fall, when fallen tree leaves provide abundant, carbon-rich compost fodder to start a pile that can work through next winter.
“Compost is basically a version of the way nature has built up soil all over the world,” she said. Winter isn’t going to stop it.
For tree and plant advice, contact the Arboretum’s Plant Clinic (630-719-2424 or plantadvice@mortonarb.org).
Beth Botts is a staff writer at the Morton Arboretum in Lisle (www.mortonarb.org).
This article has a few key points worth noting.
First of all, composting will slow down in the winter, but not necessarily stop. If you can keep stuffing your bin with more food scraps, you should (as long as you can add cover materials on top).
Second, pile size makes a huge difference- allow for the largest composting effort you can. The bigger the pile, the easier it is to maintain working temps throughout the year- let alone that it’s much more forgiving with what you throw in.
Limiting myself to just a trash can composter for the winter has been a big challenge, but I’ve been able to make it work by making sure there’s plenty of cover material with each deposit and adding red wiggler worms to the mix.
I highly recommend experimenting with them- adding just a few to the pile may be all it takes to make enough space week after week until it warms up.