Cold Composting Characteristics


Attracting thermophilic (warmth loving) microbes to your compost bin can require either deliberate inoculation or a great deal of attention to maintaining ideal composting conditions—and if you live in a cool climate or compost in an especially shady area, either may be difficult. Fortunately, cold composting (a.k.a., slow composting) is always possible, through the good graces of psychrophilic (cool loving) microbes that will happily break down organic matter in temperatures of 0-55 degrees Fahrenheit. In some cases, you may even be able to recruit the help of mesophilic bacteria, which might jump in and help once the compost temperature gets over 40 degrees, and definitely will if it gets over 80 degrees.

The biggest benefit of cold composting is that it’s by far the easiest method. The maintenance requirements are minimal, so it’s ideal for busy people who still want to help the environment, or for those for whom physical activity is difficult. You never have to turn the compost at all if you don’t care to. It’s also a good option if you have very little yard waste or grass clippings to worry about, and aren’t in a rush to use the compost in your garden. Plus, cold composted organic material suppresses soil-borne diseases better than hot composted material.

All that said, cold composting does have a few drawbacks. It can take 6-24 months for material to completely compost, and it leaves some non-decomposed material mixed in (it can be screened out as necessary). This can be minimized if you’re able to chop the organic material into small pieces before you toss it into the compost pile. Also, you absolutely must avoid allowing weeds into the compost pile, even if they come from lawn clippings, because the temperature never gets high enough to sterilize weed seeds.

Don’t miss our cold weather composter. It’s in the picture at the top. You can get a winter jacket for this compost bin, so you can compost all year long! Here are more tips for winter composting!