Cover the top with a tarp suffice that rain/snow is caught. Protect the windward side from the same.

I have often left mine uncovered and had no problems. It always freezes in the top portion. Come spring it starts to thaw. I usually build new piles in the fall so there is only a foot or more left to catch snow/rain. If your pile is a finished pile the it would serve to cover it if for use come spring.

Usually I cover compost with a thick layer of fallen leaves.

But if you have spoiled hay that you need to dispose, a compost cover sounds like a great option.

Use what you have...

The problem with an open compost pile is that the fall rains can introduce far too much moisture and your pile stops composting, due to lack of air, or goes anaerobic. A cover that will keep the rain off, or out, like a tarp stretched over the pile is all that is needed, while a tarp that covers the whole pile could severely restrict the exchange of air. Compost piles that freeze in cold weather have too much moisture in them.

ROFL.

Did I say something funny?

Kimmsr comment about a frozen pile being too wet is hilarious. I am sure its a joke.

I was also chuckling about the idea of fall rain and keeping winter snow off. Not a problem here in the arid Southwest! I shape my compost pile with a depression in the top to catch moisture, and then I pile the autumn leaves on my garlic beds and then cover with pine needles to hold them down when the spring winds come.

Actually I think kimmsr is not joking, and he is right. Obviously a dry pile will not freeze over the winter as it is indeed the water that will freeze. Granted, a dry pile will have stopped most of the biological activity prior to very cold weather, but it won't require thawing out in the spring as a solid block of ice would.

Thank you all for the reccomendations. I think I will be covering the top of the pile with a black sheet of plastic. This will keep the pile from getting waterlogged and subsequently freezing solid, as well as helping it heat up in the spring (with some warm water to help out).

He ain't joking but he's still not entirely correct.

In order to compost, one has to have moisture, no moisture, no composting. Even a bag of dry leaves will freeze because they are not at zero moisture. They may thaw out faster than wet leaves, but that's physics or something.

I have had piles at 150F in the fall, freeze during the winter and re-heat in the spring. They were not too moist, they just couldn't generate enough heat to compensate for the -30C air temperature. I've also had windrows not freeze entirely but that was because they had a sufficient snow cover to insulate them from that -30C air temperature and they could then generate enough heat to compensate for the much lower heat loss.

The mistake in his theory is confusing an out of tolerance pile (not moist enough or too moist etc.) that isn't generating a lot of warmth as it decomposes.

If all the parameters are in the range conducive for composting, some warmth will be generated as long as the micro-organisms remain active. This may extend the time it takes to freeze. Getting out of the optimal range, the micro-organisms can't generate the warmth necessary to compensate for the heat loss, they cool, go dormant and the pile freezes.

In a nutshell, a pile freezes when the heat loss is greater than the heat generated at ambient temperatures below the freezing point. There are numerous factors that come into play to affect this.

Michael, your plan is as good as any.

Lloyd

If he is not joking, he is wrong.

BTW, Compost is supposed to be moist as a wrung out sponge, not dry.

BTW, everything that I compost, has a moisture content, food scraps, straw, pumpkins, shredded paper. I don't add water to my pile, I intentionally keep it on the dry side. And guess what, the stuff still freezes! I don't dehydrate stuff before I put it in the pile.

My experience with frozen compost is what made me laugh. Too wet... ha, ha, ha.

Well, Mother Nature never covered her compost piles!

Think of all the leaves in the woods that fall from the trees and are subjected to winter rains and snows. They may freeze, but it is not contantly raining every second. So, they thaw and dry out. Ever notice how nice the soil is in the spring in the woods?

Is it really necessary to cover your pile?