Short answer - no. ;) Exposure to the weather is normally beneficial to composting process and covering with plastic is never recommended

Dave

Here is a link that might be useful: Discussion on covering compost piles

The only things that I ever cover my compost pile with is other items to compost--just like mother nature does. Just keep adding, or start a new pile year round, although in my zone (4a, IA) the pile just sits there most of the winter, it's hard to heat up a cp when it gets to -20 outside, lol. But then, the freeze/thaw process also helps to break down your pile, thus another reason for not protecting it from the weather.

(CH2O)n + O2 --> CO2 + H2O + energy(ATP)

The reason not to cover a compost pile or bin with an impermeable tarp is because it will trap the water given off when the glucose/carbohydrate is oxidized. This may make the pile too wet and stop the aerobic composting process.

An old carpet or similar pearmeable material will allow the water to escape.

Thanks for the info! Good to hear I can just leave it, less work that way.

It is an either/or type of thing. A cover that is not impervious but allows the compost to breath but also restricts the amount of water that could enter the compost pile can be beneficial, because too much water in the compost pile inhibits the digestion process. If the tarp was suspended above the compost so rain and snow were blocked that would help, but simply laying a tarp over the pile in a way that restricts air flow would not be beneficial.

"Do I need to cover my compost?"

No, but I disagree with most of the reasons given.

No, but I disagree with most of the reasons given.

There is always one who does. ;) Care to explain why?

Good answer Lloyd.

I do cover my piles. In the summer I do it because I want it to retain it's moisture. Like LLoyd says, it's not like it's a ziplock bag. It is simply covered and loosely tucked around the side so the wind won't whip the plastic tablecloth or tarp away.

In the winter I cover with 4 inches of leaves and then lay some bags of shredded leaves on top with burlap over that. I keep it going all winter (hot) by doing this. The warmth keeps the top bags thawed so I can add them to the pile the next weekend.

In the spring and the fall, the plastic/tarp covering keeps some of the rain out.

I don't use new tarps. I use old ones with holes, old plastic tablecloths, and such.

Rarely do I leave the piles uncovered. Just my preference. I find I get compost faster that way. :O)

For those of you who are concerned about the compost getting too moist, take another look at the OP's state. Too much moisture can happen during the winter or if somebody is overzealous with a hose, but for the most part, even if the bin or pile gets too wet, all you need to do is wait a couple of days and it will be too dry.

After some 45 years of composting I have never seen a too wet compost pile dry out in a couple of days, and that is why my bins have covers on them. Until I put the covers on the bins I would need to unpile the compost and either let it dry out some before repiling it or add some dry material to soak up the excess moisture when repiling it.
Based on the comments I have read here many people keep their compost piles too wet. Compost needs only to be just moist and too much water will exclude air also needed by the bacteria that will be digesting your material.

Well, maybe wet piles don't dry out in a couple of days in MI Kimmsr, but maybe they would in UT. A little dryer there perhaps?

"Based on the comments I have read here many people keep their compost piles too wet."
I know from past comments that mine are too wet for your liking, but they are my piles and I do get finished products out of them in 6 weeks if I want to. Yesterday I started a pile and as I was adding and mixing the hose was spraying a nice shower on the lot. I did one like this two days before and it's already at 40C even though the outside ambient temp has not reached more than 13C in those days.

In the winter I add at least 10 gallons of water each week to new additions which includes 4 to 5 bags of shredded leaves, 50 gallons of wet UCGs and seaweed if I have it. Mix a bit of the warm stuff from the week before and cover and there you go. And yes, this is done in temperatures below freezing.

Compost needs air, but it needs water too. We all do things differently - things that work for our climate and our likings.

So, in essence, mtnrunner, if you want to cover, then do so. If you don't then leave it be. You will soon discover what works for you and in the end it's all good! :O)

After reading all the post's, I've decided to cover mine. I have some black landscape fabric, thats as porous as Remay, so I'm hoping the black will give a little additional heat in the winter, and still let snow in.
Perhaps with straw bale sides, and a black top, it will cook all winter--who knows.

Digdirt, you don't say much about where the bin is in relation to weather effects.
If the bin is wide open and rain, snow, freezing rsin, snow and its results makes an impression on it, then you see for yourself how much moisture you are opening your bin to.
If, however, the bin is close to the wall, possibly under an overhang or behind a large shrub or bush that deflects wind and what rain and snow that effects, then you have to look at what other possible sources of moisture might effect the contents.

There is no need for a heavy tarp to prevent such moisture gaining entry, as a matter of fact, if you consider---and you should---adding to the pile throughout the winter months, then allowing a certain amount of moisture to enter by way of letting a flap whip where you lift to add to the pile is not such a bad idea.

As far as covering, a simple garbage bag, slit along the edge will cover most bins of 4 X 4 or 5' and affixing with a staple gun (T-50) as necessary to hold in place.
Works wonderful if the walls are of wood material or other that will accept the staples.
Leaving a flap open on the side closest to how you gain access to the bin makes it easy and a convincing reason to keep feeding as long as it is still actively working.
Even then, when all activity stops, the additions are better thrown on top than throwing elsewhere.
That -- depends on your weather patterns. Sooner or later though in a zone 3, 4, 5 & 6 the bin's contents will freeze.
How much it freezes again depends on your weather.
Many things contribute to whether the weather makes such effects sooner or later.
Wind...is the dryest thing in winter...there's nothing drier than a winter wind.
If it doesn't freeze solid, then you can still count on the top few inches will make it difficult to dig into it sufficient to bury what you add.
Then too, if your bin is a very active one, leading up to the cold, it may hold on to some warmth for a time. Your opening and turning over what you add is only feasible for a time and then winter catches up.

What you don't want is a bin that will accept large amounts of snow/rain/freeze/snow...and more snow and then, when a January thaw arrives all that moisture allows (as much as it can at that time) enters to freeze again and again.
Covering with a garbage bag stretched over the top will prevent such load making a point.
Snow cover will insulate--make a cover by nature itself, so there is no need to not protect it from what might be considered 'too much'.

Of course your bin is not aid confined, it should have air holes in the walls in any case.

Gotta say, this forum is always interesting, as well as entertaining.

Karen

"After some 45 years of composting I have never seen a too wet compost pile dry out in a couple of days, and that is why my bins have covers on them."

Out of curiosity, how many of those 45 years of composting took place in desert conditions? It wouldn't surprise me if compost takes longer to dry out in Michigan than it does in Utah.

I grew up in the Midwest and have lived in Utah for a little more than 15 years.

I remember having compost get too wet in the Midwest. That was probably a result of the plentiful rain.

Since moving to Utah, I've only had one batch of compost that I managed to get too wet and keep too wet. I had recently bought a root feeder that attached to the end of the hose and poked deep into the soil. I was using it every day to get water all through the compost. Needless to say, that was overdoing it.

Other than that one time, I've had much more trouble keeping the compost moist enough.

I refilled my bin a week and a half ago and most of what I added was absolutely soaked (literally dripping wet) when I put it in. I was out of town last week, but I turned the compost today and had to add water to it because it was dry.

I'm not trying to say that everybody will have compost dry out in a few days, but even now, when it's cool and not as dry as it is during the summer, it doesn't take long for compost to dry out. If you reread my earlier post, you'll see that I said to look at the OP's state. My point was that in Utah it only takes a couple of days for it to dry out if it gets too wet. I'm sure it takes longer in Michigan, but it's not nearly as dry in Michigan, so I wouldn't say that about Michigan.

When I was in Arizona, southern California, and Texas I saw much the same thing, people would tend to keep their compost piles too wet adding much more water then necessary. I would suspect the same thing happens in Utah, people look at the exterior of the pile and judge it too dry and add water when the center, where all the activity is, is moist enough to too moist. Too many people tend to keep their compost piles, and too many people tell others to keep their compost piles, too wet in spite of the admonition that a compost pile only needs to be as wet as a well wrung out sponge. I remember someone here telling someone else that leaching, water flowing from their compost, is normal when it is a good indication that there is way too much water in that mixture.

Kimmsr--It sounds like you've seen people get too much water in compost in desert conditions. They must have really worked at it, but I can believe people would do it. The most common lawn problems in Utah are due to too much water from over irrigation.

If that's the case, though, covering the compost to keep out the rain won't help, since a) there's no rain and b) it's the water from the hose that is causing the problem, so the solution is turning off the hose, not protecting the compost from nonexistant rain.

i'm new gardener. reading gardenweb has been the best education for me. many experienced gardeners sharing, comparing notes. i love it. thanks to all of you for posting and sharing your wealth of knowledge. there are different views, which provide perspective. thanks all.

I have been using a material called Toptex purchased from a company called Flexible Lining Products http://www.flexiblelining.co.uk/agricultural-products - it is expensive but it really works and unlike tarps or plastic this material is 99% waterproof and fully breathable. My material is 4 years old and still working as new, albeit lost the green colour due to dirt as expected. Hope this helps http://www.flexiblelining.co.uk/agricultural-products

Old thread but The question did not appear till today for me, 9 years later. As stated above, I think covering with black water proof material is the best option, provided the following is adhered to... Water appropriately for your area... mY pile is 3 ft wide by 12 feet long. I use rubber roofing (wonderful stuff to have around been using one box of it bought at a box store for years, still use it. Buy it it has so many uses) Anyway, I have a stake driven inground so its sticks up 3 ft at both the ends of the pile. my length of rubber is 13 ft x 4+ ft and is laying over a cable attached to the top of each stake......forms a long teepee...wind blows a little down there so I use just small metal yard u shape to hold sides down. Easy on easy off, plenty of heat, water when you want/need too. and to the rest of ya, Air Flow! I think air helps! Just my two cents!

I find siting compost pile under tree cover makes this a non-issue. Some rain gets through but never too much. If needed add water from time to time. Limited direct sun means rarely dries out or at least not quickly. Of course those in other climates may have different experience.