Yep, I've found that covering the pile for the sake of moisture retention has better results than worrying about air circulating throughout.

Ken,
Surfed your site, very interesting.

Are you acquainted with Robert Moore, TheSoilGuy ??

thanks,

Thanks. The two who responded on my "weed free gardening" post do not seem to share your sentiments.
No, but I will look him up.
So many of the posts and questions asked on this forum deal with the very basics of composting and yet waterproof insulating could remedy many of the issues posted on . . . all by itself.
It helps maintain moisture levels, speeds up the decomp rate, kills far more weed seeds, allows for smaller piles to accomplish what would otherwise require larger piles, and can dramatically reduce the amount of work needed to obtain similar results . . . and yet no one is talking about this anywhere else much.

Some folks like to make the walls of the compost pile from Hay or straw to keep insulated and cover with tarp. A friend of mine surrounds his tarp with burlap to keep it moist.

What?!?!? More spam?!?!? Just kidding. I actually know the definition of the word. Those two were asses toward you. Even if you were selling a product, there is no reason to be so childish. I've been admonished for calling others on BS on this site or for being argumentative. Yet, when people are truly rude and way out of line, that's acceptable. Maybe this should be hypocriteweb instead of gardenweb. Oh well, I come for the rare gems. Anyway. . .

I have wondered before why a pile needs air from the sides if you turn it regularly. The sides don't allow air flow in at all. I seriously doubt there is air flow beyond a few inches into the pile because of a breathable bin. Air isn't flowing in if you are keeping the pile hot. Leaving just a little room for gases to be released should be plenty sufficient between turnings I would think.

I couldn't be sure, but I think the secret is the waterproofing, not the insulation. My heaps used to need watering all the time to keep them ticking over, and then I salvaged a load of old canvas from a trailer-tent and used that to cover the heaps and they needed a lot less water and stayed hot better. Then we had a big square of heavy black plastic left over from a building job and I used that to completely cover one of the heaps and that one now runs hot and moist continuously. In fact, it runs as hot as my humanure heap! I resisted plastic for ages as I thought it would starve the heap of oxygen, but even though I never turn the pile, it seems to be going better than ever. The back wall of the heap is stone, the sides are hollow brick and the front is wood, so I guess the sides are insulated, and the heap has plenty of 'browns' in the form of straw and wood shavings.

Maybe the secret of not going anaerobic is more down to what goes in to the mix than in turning...

I agree that the first step is just to cover with plastic and that the retained moisture has a DRAMATIC change on minimize the critical moisture loss. And be sure, a simple thin sheet of plastic does offer substantial insulating effects by simply trapping heat and some air. Look how many cover their windows in winter with a thin film. But I have found that thick insulation goes much farther in allowing the high temps (140 +) to be found even on the very surfaces of the pile. Without access to the giant bubble wrap that I have stumbled upon . . . one could insulate with one layer of plastic covered with dry straw or leaves . . . and then another layer of plastic over that to keep the the straw or leaves(insulation)dry. I have found that if you put the "insulation" under the plastic, it will draw a lot of moisture up and out of the primary materials of the pile.

My other interest in the insulation is that it has the potential to allow high weed seed killing temps to be hit in even the smallest piles. In theory, as long as you have all the right ingredients, a mere handful should be capable of achieving 140 or above.
For anyone interested, I wrote an article asking why residential urinals do not exist in mainstream America. It talks about how a compost pile makes an ideal discharge point for the urine.

Here is a link that might be useful: Urine in compost

Sorry I meant, he surrounds his compost (not tarp) with burlap.

You bring up a good point about window insulation. It's important to note that it's not a thin layer of plastic that is doing the job. It's the air gap the plastic creates between it and the window. If the plastic touches the window you will receive so little insulating effect it isn't able to register a full degree F different. The heat will leave your home through conduction from one surface to the next. Conduction is faster the greater the temperature difference between the outside and inside. I do thermography, in case you might wonder how I'm so sure.

So, maybe it would be even more effective if you provide an air gap between the plastic and the compost. Like maybe prop it up in a couple spots with a branch or something. Then you have retention and better insulation.

Yes, totally true about the role air plays in insulating. I like your idea about using obstacles to prop the plastic up a little, but don't you still need two sheets with space between? Otherwise the high temps are free to gather at the surface of the plastic anyway and losses will still take place through the plastic as you said. Placing a layer of dry straw between two sheets would work as I mentioned earlier, but yes the "air gap" is critical for insulation as you said. "I'm lucky to have bubble wrap>
As someone else mentioned (as do I) the moisture retention alone is worth covering with plastic . . . period.
One thing to be said though is that courseness of material and partical size are still very important and materials that tend to mat and go anerobic will certainly still do that if covered up. That is why I love composting horse manure so much . . . the clumps themselves tend to stay loose and separate as do the bedding materials (straw or wood shavings) and the C/N mix is ususally good enough to generate substantial heat as long as moisture is(stays) present.

Interesting concept. But is it in fact the insulation effect doing it all, or does the whole pile being moist, allowing for more activity by the micro guys play a large part.

If a 4 foot across, round pile in wire, has the outside 6 inches of the material too dry for thermophyllic activity, really you only have the center part doing anything. If the whole pile has sufficient moisture, then the whole pile could be generating heat.

In the tumblers I get a much more even distribution of moisture than the piles. But for sure when the overnight temperatures fall into single digits (Celsius) there is a lot of heat loss and insulation would be an asset for sure. I could use bubble wrap around part of the tumblers. I wonder if an old swimming pool cover would work? I've seen a few being thrown out now and again.

Have to ponder this some more. Good topic, thx for bringing it up.

Lloyd

A compost pile of 4 feet width or diameter will be self insulating because, as Lloyd stated, the digestion is taking place in the center of the pile. If you need to insulate your compost pile to keep it from freezing in winter that may indicate you have too much moisture in the mix.

But . . . if you insulate that same 4 ft pile, digestion will take place throughout the entire pile, not only in the core. That is what is so remarkable about the effects of insulating. The only reason digestion is limited to the core of a "self insulating" pile is because so much heat is lost that the outer layers are not able to maintain the temps that those particular bacteria thrive under. This forces you to have to turn your pile in order to have your outer layers "digested".
I built another pile yesterday that is about 3 ft high and 6 ft in diameter. I sprayed the material, and covered it with first a thin plastic film and then a sheet of my bubble wrap. By the time I got home last night from fishing, the top of the bubble wrap was warm (indicates heat loss due to weak insulation)and immediately under it between the wrap and the plastic film was very warm . . . and immediately under the plastic film was hot enough to burn my hand (at least 120 degrees).
My pile remains self insulating to a point in that the core will be hotter than the surface, but the surface of my pile will still be some 50 degrees hotter or more than the surface of your uninsulated pile. Because my entire pile is actively digesting and a more ideal environment for the bacteria has been created . . . a more complete breakdown will take place, in a much shorter time, with far less work required (watering and turning).
PLEASE!! Anyone that composts in a way that generates heat, and doesn't at least cover your pile with plastic, try this!! If your core has heat (and you moisten the outer layer) you should see results in as little as a day or less. Then post back . . . this won't take months or even weeks to test or demonstrate.

Here is a link that might be useful: PANDSCORP: Outside-the-box ideas

I think I feel the need to go visit a few furniture stores to see if I can liberate some nice big pieces of bubble wrap.

How many layers do you use, pandscorp?

Well, it is like your house . . . a little does a little and a lot does a lot. Start with at least a sheet of plastic (since it is summer). Then if you want more dramatic results, be creative and cover that with any dry insulative material that you can easily come up with. This could be straw or dry leaves . . . or one of those styrofoam panels . . . or even fiberglass batts if you can keep it dry by sandwhiching effectively between waterproof material. Large(or small) plastic garbage bags filled with any insulative material, carefully tied off and stcaked on your pile would work well too. You want to make it effective . . . but easy to do and deal with.
If you can locate the bubble wrap sheets, then that is a great and simple way to go! Otherwise, be creative.

The main reason plastic works for windows is it stop/slows air leaks, air gaps have little R value.

The sun radiates heat, even on cloudy days. Check your compost just before sunrise. This is a better benchmark how your microbes are doing. A portion of the daytime heat will be residual in the pile, depending on factors.

" . . .The best insulator is a vacuum, completely empty space. If there are no
molecules, there can be no vibrations. A very good insulator is air.
Gasses like air do no transfer heat very well because the molecules are so
far apart from each other. Wind can make air transfer heat because the air
molecules carry the energy as they move. If the air molecules cannot move
much, they cannot carry the heat energy very far. A bunch of air-filled
plastic bubbles arranges in a honeycomb pattern is considered an excellent
insulator. Dry wood has a great deal of empty space inside it. Dry wood is
a good insulator, too."

Dr. Ken Mellendorf
Physics Professor
Illinois Central College

AS FAR AS THE SUN'S ABILITY TO ADD HEAT TO A PILE, THERE IS NO MISTAKING IT. IN FACT A PLASTIC SHEET WILL ENHANCE THAT EFFECT. HOWEVER A HEAVILY INSULATED PILE WILL BLOCK THE SUN'S RADIATION AND HAVE TO RELY SIMPLY ON MICROBIAL ACTIVITY, WHICH IS A FAR GREATER SOURCE OF HEAT IN THE PILE THAN SUNSHINE. WHEN I PULL BACK THE INSULATED LAYER ON MY PILE EARLY IN THE MORNING, THE TEMPS ON THE SURFACE OF MY COMPOSTING MATERIAL WILL SCALD THE SKIN . . . AND THEY GET HOTTER THE FURTHER IN YOU GO.

The Composter that is completly false all insulation relies on air gaps

I have been wanting to cover my pile but haven't found something big enough that looks good its a 10 yard pile

Pandscorp I suggest changing your name will get you more positive conversation They instantly think your selling something

It is thermophilic bacteria that generate the heat in a compost pile, sunlight does not contribute a significant anything except to cause moisture evaporation of the surface it hits. The thermophilic bacteria need a certain level os moisture to work and even in an insulated compost pile that level would not be on the edges and that is why the digest the material in the middle of the pile so readily but do not touch the edges until the pile is turned inside out.

Yes, the thermophils generate the bulk of the heat, but as you know, they exist in a wide range of conditions, but thrive under ideal. This includes moisture content and temperature . . . the thermophils thrive at the high temps they create. To suggest that A. there isn't enough moisture at the surface of an insulated pile - or - B. that the bacteria do not touch the edges of that pile (insulated) is simply not the case at all. I have extreme active digestion taking place right up against the surface of the plastic sheeting . . . just as good as in the center. The natural rising of heat causes both heat and moisture to congregate at the top which in fact often creates a more ideal condition at the top of an insulated pile than in the core which will loose some of its moisture which is then trapped at the top of the pile.
Now of course not all insulation is waterproof, but I think you would find the same results if you insulated with two feet of straw . . . there would be solid activity on the actual surface of the pile itself (under the two feet of straw) all the way through to the core. The surface of the straw may be cool, but in this case the tsraw is your insulation and not really part of your pile.
THE BEAUTY OF COVERING WITH PLASTIC AND EVEN MORE SO WITH INSULATING IS 1.THAT YOU DON'T HAVE TO TURN YOUR PILE FOR THE SAKE OF GETTING OUTER MATERIAL INTO AN ACTIVE ZONE 2.yOU HAVE FAR LESS NEED TO WATER 3. WEED SEEDS ARE KILLED THROUGHOUT ALL THE WAY TO THE SURFACE (AGAIN WITHOUT HAVING TO TURN)!!! Now if you do want to turn an insulated pile to infuse additional oxygen then yes you will certainly be giving it a boost, but I am finding that an unturned insulated pile will out perform an uninsulated pile that is turned because the environment is far more condusive for the thermophils to thrive. We are talking better results with less work.

Sounds plausible to me.
Always experimenting, I'm gonna try it.

I do know, when I covered a pile with 2" of screened compost, the pile stayed hotter longer, and microherd was active at the top.
thanks,

It does make sense. Rot happens sooner under heat and humidity. That's why rot happens quickly in the tropics.

I still wonder if it is more of a case of containing moisture (or preventing drying) versus the actual insulation value.

I have and do cover some piles with the intent to retain moisture and it works. The stuff up against the tarp is wet and the stuff with no tarp dries out for a few inches into the pile. The stuff on top just under the tarp is well moistened and there has to be some composting activity taking place.

Yet there is plenty of looseness in the tarp to allow for air infiltration.

Interesting.

Lloyd

Thanks LLoyd.
I did emphasize the significance of the moisture retention even in the article on my website that was written before I posted here. I agree, that it plays a huge part in what we are dealing with, but I think the insulation takes things to a whole new level . . . and of course will play a far greater role once temps begin to drop this fall.
As you can see, the results of my first side by side comparison are very impressive so far.
I guess now I will need to do a three pile set up to compare conventional to covered only to covered and insulated.

I will monitor your experiment with interest Ken.

And for sure, once temperatures begin to subside in the fall, an insulating factor comes into play big time. I am now considering using bubble wrap material (pool covers) for the mutli-tumblers to see just how much effect there is in the fall.

Lloyd

We managed to scrounge an old tarpaulin off a neighbour. This freed up a big black plastic sheet we'd been using to cover the wood pile which has now been converted into waterproof compost covers!

Oh, and Pandscorp, hope you don't mind me mentioning but THIS IS SHOUTING (in capitals) and is considered rude. It's best avoided in case anyone takes it the wrong way.

The www.pandscorp.org website appears to be down :(

Is there anywhere else I can read further about pandscorp's experiments?