Not really.

That is - it isn't impossible; everything rots, after all. But the process most of us mean when we talk about composting is one that would be very difficult to achieve in a plastic bag.

The main problem is that the composting process uses quite substantial quantities of oxygen. Oxygen is probably the limiting factor in most of our piles. Or - that's probably too much of a generalization, but the other limiting factors (enough moisture, enough carbon, enough nitrogen) are discussed in a forum like this over and over, and I'd guess most readers are familiar with them.

Punching a few holes in the bag will not come anywhere close to providing enough oxygen to keep a sizable population of aerobic bacteria flourishing. So one of three things will happen: anaerobic bacteria will do the work instead (stinky), or fungi will do the work instead (can be slow), or nothing much will change.

I think you can probably make nice leaf mold (fungal decomposition of leaves) in a black trash bag. It takes a lot longer than a compost of mixed feedstocks (lots of different kind of ingredients), but it could be useful to you if you can be patient.

I left a bunch of yard waste in black plastic bags over the winter, and they were partially composted when opened in spring. Some more than others. But they did break down pretty well.

I do remember that at one point in the winter, there was a certain odor from the bags that wasn't pleasant.

2 things limit that possibilty, lack of suffircient air and lack of sufficient volume. As has been already pointed out some people have seen some digestion happen and the result is most often vile smelling, anaerobic digestion (in the absence of air), that may have disease pathogens that have developed. Anaerobic systems are very good places for disease pathogens to develop.

kimmsr, This is interesting, please name some of the diseases we could expect. thanks

A side effect of anaerobic decomposition is the production of alcohol which may damage plant cell walls and roots. Anaerobic soil conditions can occur naturally (over watering & soil compactation are prime culprits). Compost has too many variables, so it is natural that generalities are use in describing it. And one such is aerobic is better than anaerobic. But to be fair there has been some evidence that anaerobic will suppress some very specific pathogens, but it proved to be difficult to field reproduce the results of that study. Back to generalities, aerobic well aged compost will be populated with the bacteria that will out compete with pathogens. Another generality is that anaerobic compost does not have high enough temperatures (mesophilic) to effectively destroy most pathogens whereas aerated compost has temps (thermophilic) that will be high enough to achieve thermal-death-point values (that is a neat word), this temperature would have to be maintained for about a week (with some turning) to be effective. At this point you might be assured that at least you not adding pathogens to your garden, letting the compost cool down will repopulate with the nice bacteria & fungi. Sounds simple, but all compost piles are a combination of aerobic & anaerobic events, it is just a game of numbers.

Just wait, designer compost products are in our near future.

Here is a link that might be useful: Disease Suppressive Compost

What I HAVE done for several years is make leaf mould in black bin bags. The leaves need to be swept up when dry (damp leaves give a yucky mess), put in the bag which is tied and then a few holes put in with the tines of a fork. You then leave it in a corner and forget about it till next year. Some leaves work far better than others (I had oak, sycamore, beech, hawthorn, birch and fruit trees mainly).
In the UK (small island, crowded, short on landfill) the local authorities used to give us free composting bins to encourage us to put less waste in the household rubbish. Is there a similar scheme anywhere in America?
The leaf mould was a great mulch.

tumblenes, that is interesting, thank you. I would still like specifics on what disease pathogens develop in anaerobic conditions. Also, are you saying that compost leachate has some percentage of alcohol?

Another thing occurred to me. Composting at very high temps kills some of the weed seed in manure, hay, etc. Composting in anaerobic conditions would rot most of these seeds. Is that not correct? Maybe combining both methods would be better in some situations.

"Is there a similar scheme anywhere in America? "

Not nationally, but some communities will provide free or reduced price bins, usually on or around Earth Day.

Thanks, bpgreen. I'll look out for that.

Has anyone ever used one of the ComposTumblers that composts 18 bushels in 14 days? All you have to do is turn the crank once a day to tumble the drum and turn all of the composting material without alot of time or backbreaking work. I am very interested in buying one. The Price is about $500.00. We have been composting the last two years here in eastern Pennsylvania using a 3 bin system. We have horses etc, so we have the raw materials, but my husband has a hard time keeping the pile above 120 degrees and even with his loader on his small tractor it still takes him a couple of hours to turn one compartment into another every 3 days. I am not to anxious to use this material because I think the compost causes alot of weeds in my flower and vegetable beds. We are constantly battling weeds. We do live on 34 acres with lots of hay fields, but still I think a lot of the weeds in my beds are from the compost which doesn't heat up to above 120 degrees. I have read that you have to have your compost pile between 140- 160 degrees for 14 days to kill the weed seeds that are in the manure of our horses that graze on our hay fields. The ad for this CompsTumbler says that their 8 year old grandson can turn the crank with one hand and a lollipop in the other hand!!. I was hoping that someone on the web has bought this and likes it.

bean,
certainly the most serious are the fecal pathogens, such as e-coli, a good reason to avoid slaughter house raw cattle manure. Generally, the pathogens come from the materials you compost with, your garden. I have experienced anecdotal evidence that compost lessens tomato wilt. Is compost leachate the compost pile drippings? That tells me that the compost may be over watered. As far as rotting seeds, well they are tough little guys, you see them rotting? Keep in mind gardening should not be stressfull, develop compost & mulching techniques that serve you well.
Suggested reading "teaming with microbes"

karenpa,
yep, I got one. A 8 year old boy can turnit with one hand? Who are they kidding? I can barely do that, so I doubt it (ok, when empty), and it might be dangerous as the tumbler can on occasion to apply a reverse force, if the user doesnt have the strength to conteract that then the handle might spin & injure.
Will you have compost in 14 days, yes, but 1/2 finished.
As far as reaching high temps, yes I think it is easier with a tumbler, but there still is a learning curve. I dont compost with manuer (or with tractor!), but it boils down to the basic C::N ratio. How do you know if your thermometer is telling the truth?
here is what I suspect, turning the pile at 120F will temporarily lower the temp, so maybe turn less often, but do turn at 160F so you dont over cook. The most difficult thing to do is not to over water.
Will a tumbler save you work? No, it creates it. Yes, I like it. Some farm people make their own. Multiple motorized ones as well. PT03 made one.

Here is a link that might be useful: tumbler

Aside from the disease pathogens that affect humans, such as tetanus, there are numerous plant pathogens that can develop in an anaerobic environment. E-Coli would not develop in a plastic bag of leaves unless some manure was added, but that anaerobic environment would be a really good growng environment for it to grow even more. Most all disease pathogens, both human and plant, grow better in an anaerobic environment than they will in an aerobic environment.

"Most all disease pathogens, both human and plant, grow better in an anaerobic environment than they will in an aerobic environment."

I don't believe thats true.

Aerobic composting generates higher heat, which kills off the various nasties.

Anaerobic decomposition, such as occurs in a bio-gas digester, (eg sealed bladder full of manure) does not create the heat, but

" Although heat does not play a part in the destruction of pathogenic organisms in anaerobic composting, they do disappear in the organic mass because of the unfavorable environment and biological antagonisms. They disappear slowly. The composted material must be held for periods of six months to a year to ensure relatively complete destruction of Ascaris eggs, for example..."

Here is a link that might be useful: anaerobic composting

Thank you david for the info from Washington State. It would seem the most serious adverse effect of anaerobic decomp is methane gas.

So, a fairly short term of submersion would destroy weed seed and speed up decomp. Removing the material to an aerobic compost area (perhaps mixing with other compost) would finish it. I personally like this idea for certain types of materials. Thanks again.

I've seen over the years several interesting applications of anaerobic decomposition, perhaps the simplest being a rubber bladder over a sealed septic system, the methane was captured, under slight pressure from the bladder, and used for cooking. With that system, the animal waste worked its way through the duel tanks of the septic, and then as more was added, some left, which went to fertilize a fish pond (where I came in). Occasionally, they would drain the pond, shovel up the mud, and go use it in the garden. I thought it was pretty clever, usually they just shovel the manure straight into the pond or the garden, but this particular set up was in the Sahel where lack of firewood was a serious issue.

This being the USofA, they do it on a slightly different scale, witness the link below.

Here is a link that might be useful: biogas generators

The primary reason for deliberately composting with anaerobic digestion is to capture that gas for use in heating or generating electricity. While there is renewed interest today, especially at CAFOs, how to do that has been known for more years than I have been around, like back in the 1930's and maybe before that.
Whether you believe that disease pathogens develop in anaerobic conditions or not is immaterial since they do.

"Whether you believe that disease pathogens develop in anaerobic conditions or not is immaterial since they do."

I don't believe I denied that disease pathogens develop in anaerobic conditions, botulism is the immediate example that comes to mind.

I do, however, take exception to your blanket statement that

"Most all disease pathogens, both human and plant, grow better in an anaerobic environment than they will in an aerobic environment."

I would be most grateful if you could direct me, as well as the other readers to this forum, to a source that substantiates this claim.