There are many types of composting. If you're going to cover a compost pile to insulate it, I would suggest books of straw. That way the pile is still breathable. Burlap would also work, but I'm not sure how well that would insulate it. A pile shouldn't be covered with plastic.

Thats what I'm wondering. Why not cover with plastic? The sides are made with straw bales, several inches apart, so sides can breathe. Anerobic? is that one of the types I'm thinking of?
Not wanting to be controversial, just wanting to learn how to keep it working all winter, and having the best compost by spring.
And when I mow my leaves and grass together--is that considered greens--and browns?

Anaerobic composting is considered "bad" composting as in "not desirable and needs to be corrected". The fact that plastic encourages it is why plastic is not recommended.

A pile that goes anaerobic is very foul smelling and encourages the growth of many types of harmful bacteria. Exposure to the weather is one of the main stimulants for the composting process so while you wouldn't want it to be flooded of course, you also don't want it totally protected from normal weather patterns.

If you are simply wanting to lay a tarp over it to keep off snow for example, you could as the sides are open to air but you will risk the pile getting too dry too. Since you and I share the same winter weather patterns, I can only say that I have never found covering my piles in winter to be of any benefit and when we do get a good snow fall the weight of the snow just seals any cover down over the pile. Before you know it, it has gone sour. On the other hand, straw or old hay layers work well to keep the pile semi-protected yet still aerated and the straw just adds to the amount of finished compost. JMO

Mowed grass clippings and leaves would be considered a combo green/brown (carbon/nitrogen) but would be more green than brown because the tannin in the leaves makes the carbon in them less available initially.

Dave

Excellent, thats what I was wanting to know.So, I guess as soon as I finish with the leaf and lawn mowing (incidentally, my straw bales are composting too, I just layer them in the pile when they break down, and replace), I will just cover it with a good layer of straw, and wait till spring.
And watch it smoke--such a good feeling!
Thanks.

ceresone - oh yeah, watching the heat come off your compost is such an excellent experience! I think anaerobic and aerobic were probably the two kinds you were talking about. Sorry if I sounded snarky. You definitely want aerobic, so you don't want it too wet or smothered with plastic :) I think compost covered totally with plastic would become a slimy, stinking mess. But you have the straw bales on the side, so you seem to be in good shape. Happy composting!

Og, gnomey, you sounded just fine--I was having one of my more frequent "senior moments" and couldnt think of the 2 kinds, and was wondering the disadvantages of plastic.
and, too, concerned with just the right balance of water--methinks I worried too much. Thanks for your answer too.

I think people who live in really dry climates like to keep their piles covered to retain moisture. I imagine some people who live in really wet climates, might keep their pile covered to keep their pile from getting too wet.

I would say an aerobic pile is undesirable from an odor standpoint and that is it. Anerobic bacteria aren't bad, they just smell that way.

Unless your pile is enormous, I would just plan on letting it freeze over the winter. In the spring, the pile will thaw out and continue to decompose, nicely. The freezing helps break down cellular structure and thawing spring piles become active and decompose fairly quickly.

There are three types of composting, aerobic (in the presence of air), anerobic (in the absence of air), and vermicomposting (using a certain type of worm to digest the material). Most every one does the aerobic composting because of the special equipment needed to properly compost anaerobically, something that very large operations often use so they can capture the methane gas produced to use to generate steam which can be used to generate electricity as well as provide heat.
Simply putting a cover on your compost pile will not change it into an aerobic pile, that most often happens when too much moisture is added to the mix. What a cover can do is aid you in controlling the amount of moisture that gets into your compost because that cover will limit how much rain and snow reach that material. Unless the cover is plastic or some similar material and totally covers your compost it most likely will not slow, or stop, the infiltration of the air that the aerobic bacteria that are digesting your material need to function.