I live in Newfoundland Canada. The winters here are severe, but alternate between freeze, some thaw then freeze again, usually lots of snow too. My Question is what is the best way to have a non container compost heap? Should I cover it for the winter? I use wood ash from the woodstove, household veggie peelings, grass cuttings, leaves and twigs, old disease free plants from the greenhouse and garden.... I didn't cover it last year and when Spring eventually came I found a stinky, slimy heap of nasty unusable stuff :( What do you suggest I do to have usable compost? I can't turn it in the winter, it's frozen solid!
Stinky and slimy sound like an anaerobic environment in your pile. This can be improved by turning the pile several times in the growing season. You may also need more "browns", things like twigs or chopped fallen leaves (run over them with the mower). Grass clippings are best left on the lawn; they compost in place quickly and reduce supplemental nitrogen needs by 25%. Grass clippings are also notorious for matting down and creating a foul smelling, slimy mess. It works OK in the fall when there are leaves being collected and dispersed among the grass. Most backyard piles are not going to stay "hot" in places with severe winters. Turn the pile at the end of the season and add a nitrogen source like blood meal or nitrogen crystals. This keeps the pile working as long as possible. Eventually, winter temps will outstrip the pile's ability to stay warm. Covering it limits air circulation and is not desirable. Here are more details: https://www.gardeningknowhow.com/composting/basics/winter-composting.htm