FYI, You can see plenty of images of industrial sized piles by Googling "compost fire." I also Googled "backyard compost fire" and came across at least one incident in which a plastic bin had burned up. Certainly very rare though. Spontaneous combustion is a strange thing. I suspect it begins on a microscopic level. It only takes a tiny volume of material to start feeding on itself to get it started. An itty bitty spot in the maelstrom where the conditions are just right for a few minutes. You couldn't stick a thermometer in and measure temperatures capable of combustion though.

Yes up in Wisconsin we get a ton of rain and especially snow, so that is encouraging. Lots of bulbs have naturalized and I'd hate to lose that pretty spring show. That being said, so do you guys mulch and cardboard/paper your beds once per year? Since we get this mulch/compost stuff, that is a "can do." i guess timing depends on zone, but perhaps the best time to Paper and mulch would be after the green shoots of the spring bulbs have died back in early to mid summer. Does that make sense?

Wow, this "discussion" is kind of going off the rails. What I said, Lloyd, was that "As in, you squeeze it and a stream comes out." That's what your "Composting for Dummies" reference smartly said. I suspect a lot of compost piles are thus not too wet. Mine sure aren't. Compost is indeed revered for it's water retaining capability. What we're talking about is squeezing a stream of water out of it. No, it isn't revered for that. The pile should drain freely specifically in order to avoid getting piles that are so wet that you can squeeze liquid out of them. We're not talking about wanting leachate. We're talking about allowing aerobic decomposition. It occurs to me that snowpack is probably important in this regard. That is, snowpack on a compost pile will (1) compress the pile and make it less permeable, (2)make the pile less accessible for proper turning and ventilation, and (3) dump a load of water on the compressed and impermeable pile. That being the case, I guess I would say that if you live where you get a lot of snow in the winter, yes, it probably would be smart to cover the pile then. That doesn't apply to me, and that's probably why I've never seen the need for it. Gumby, I most certainly didn't first bring up the "too wet" questions. Go back and read. Lots of discussion about compost wetness. I was just trying to get some information on the table. The only thing I'm challenging here is your comprehension. I have a bunch of posts here because I find this an interesting topic. My apologies. The title of the OPs post was "Covering a compost pile...is the tarp really necessary?" That's precisely what we're talking about. But I'll bow out and leave everyone else to figure it out.

Only humans do 'composting'. This is a very narrow interpretation of composting and I believe it IS splitting hairs :-). 'Compost' (the noun) is broadly defined as "organic matter that has been decomposed and recycled as a fertilizer and soil amendment" and 'composting' itself (the verb) as "nature's process of recycling decomposed organic materials into a rich soil known as compost. Anything that was once living will decompose. Basically, backyard composting is an acceleration of the same process nature uses. By composting your organic waste you are returning nutrients back into the soil in order for the cycle of life to continue. Finished compost looks like soil–dark brown, crumbly and smells like a forest floor." Does nature 'compost'?