I've had better luck with coffee grounds when I don't have a great big pile of grounds and nothing else. When they're by themselves, they tend to get compacted and sometimes repel water. I get better results when they're mixed with shredded paper, leaves, etc.

As for why there aren't any worms around, are there worms in the soil around there at all? Worms migrate very slowly, so if there aren't any to start with, the coffee won't cause their spontaneous generation. If the worm population was limited to start, it'll take time for the worms to start multiplying. How long has the coffee been piled where it is?

They need some carbons mixed in to heat up and start cooking. The process requires diverse components with a somehwat balanced ratio of carbons and nitrogens. Other wise it won't cook and it ain't compost. It's just used coffee grounds. ;)

Dave

I'm not wanting these to compost, just wondering why they aren't creating any heat by themselves with the nitrogen they contain. Originally the pile was more than a cu. yd.(2 months ago) and my lawn and gardens have received generous amounts. My compost pile is huge and decomposing nicely with grass clippings, leaves, and straw.

We have worms everywhere throughout the yard except in this pile, big leaf mulcher that I am. I'm doubting if they do anything for the compost pile or if the worms really love them all that much? For all I know, they may be simply disappearing into the soil as is.

A pile of coffee grounds as you describe has no bacteria in it to cause breakdown and subsequent heating. And the bacteria use the available nitrogen to assist in the consumption of carbon. Oxygen is needed also and I suppose there's little in the pile as is. By themselves 'greens' will definitely rot and quite likely smell as that's an anerobic(sp)condition. That kind of breakdown produces little heat if any. I really don't think worms would like that environment since it's so concentrated. They do like the grounds when mixed with compost - kind of gives them a caffiene kick. Hope this makes sense.

jbann - bacteria is everywhere, including in those coffee grounds.

Maryann, I'm surprised they haven't heated up. One time I filled a 10 gallon tote with coffee grounds, intending to put them in my compost pile. A few days later when I went to put them in the pile, they were very warm. I was surprised.

Deanna

I don't know what is going on with your stash, but I do know that if you mix them in a compost pile, they will help heat it up, and if you sprinkle your lawn or top dress beds (very lightly) with them, they will attract worms. I also know that the worms in my worm bin love UCGs. If you doubt it, why don't you try it? :-)

gardenfanatic - I'm sure you're right on when you mention bacteria being everywhere. Consider that coffee is made with very hot water and the grounds are close to sterile after the coffee is made. Then they're piled into a bucket while still hot. One would think that the little exposure to air when being piled up, although cooled, wouldn't give a bacterial colony a sufficient chance to establish itself. Since they become compacted I would think that mould would have a better opportunity to thrive. Just trying to give maryann a heads up as to why her pile of UCG won't heat up like a compost pile does. Thanks for making me think about it though, I need that occasionally ;-)

I've been wondering the same thing...

FWIW, I've been getting a lot of UCG for the past 6 months or so, and my observations have been:

1) You can stockpile UCGs and they will just sit there and do apparently nothing. Won't heat up, won't attract a bunch of worms, it'll just sit there.

2) Given enough time, the pile will start to decompose anaerobically

3) Mixing UCGs with leaves, and only leaves, does nothing as well. Given enough time, worms will start to creep in, but the pile won't heat up.

4) Mixing UCGs with straw will give you a super hot (160F) compost pile and it will sustain this temperature for a few days anyway.

I'm still experimenting with using them as a soil additive and as a light mulch, but they really seem to be greening up my lawn...

Cheers,

Tim

I just noticed that the pile of grounds in the OP was 3 cu ft. That's not nearly enough to generate any heat even if it didn't get compacted. It's probably just enough to form a crust to make it repel water, go anaerobic and make itself inhospitable to earthworms.

My experiences have been different from Tim's regarding UCG and leaves. My compost has gotten above 160F with just UCG and leaves. I think the key is not to layer it, but to try to mix the leaves and UCG together. Leaves can mat together and so can UCG, but when they mix, they can really heat up, although they may need to be turned more than some combinations. The difference you saw with straw leads me to believe that the UCG/leaves mixture may have gotten too dense and either gotten too dry or else anaerobic.

Given all the right conditions a pile of nothing but coffee grounds, or any other relatively high nitrogen material, will heat up. How much moisture is in that pile? Too much? Too little?

Thanks for all your thoughtful responses. BP, your conclusions are logical. The pile is dry and dense, it's my stockpile to fling upon the lawn after screening.

Maybe I have lots of worms everywhere else cuz I have mulched with lots of leaves and UCG everywhere else but I couldn't prove they're EATING them, they may just like to roll around in them.

Hmmm... it's always tricky to try and figure out why other people's opinions are contrary to actual field trials...

So, we'll tackle the pure UCGs first. Last fall I filled a 4'x4'x5'high compost bin with shredded leaves(for storage/leaf mold). As the leaves settled (fall, and over winter), I put pure UCGs on top. By spring, this particular pile was about 50% leaves and 50% UCGs. As the weather warmed up, my 2 other "normal" piles heated up and started cooking again. The leaves/UCGs pile stayed cool/ambient. I finally decided that the UCG's weren't going to start composting on their own, and decided to spread them on the lawn. All of them. The top foot or so were just as I had put them on - damp, dark, pure UCG. The next 2 feet or so had started to decompose anaerobically - a little bit of yellow/white fungius type material, and a little stinky. But no heat. And no worms at all through 2.5+ feet. FWIW, the leaf layer underneath was loaded with worms.

Now, for the leaves mixed with UCGs - I mulched my vegetable garden over the winter with a layer of shredded leaves, followed by a layer of UCGs, followed by a layer of straw. Leaves about 8" thick, UCGs about 3" thick, straw about 6" thick. Mulch layers were removed early spring, with straw/UCG mixture into one pile and leaves/UCG mixture into another. Each pile was about 4'x4'x2'high with the majority of the UCG ending up in the leaf pile. The straw/UCG pile started to heat up, so I decided to put them back on top of the leaf-mold-to-be, until it cooled down. As it cooled, it was very apparent that the UCGs had been consumed and that there was still plenty of straw left, so I added more coffee grounds to it, and it heated up again with 24hrs and even now, a week or so later, it is still over 140F. The leaf/UCG mixture never heated up, so I decided to use half of the mixture to mulch my brassicas, and with the other half I started a worm bin. The brassicas are doing well, and the worms (hijacked from one of the other compost piles) are doing well and seem to be happy. (And the grass is the darkest green it has been in years).

Now, where the confusion comes in on my part, is why UCGs/straw seem to heat up without troubles, while UCGs/shredded leaves does not. Yet, shredded leaves/grass clippings heat up and compost normally.

Similarly, with the supposedly nitrogenous materials - grass clippings become stinky and gooey within 48hrs, yet UCGs will stare at you and do nothing for weeks on end... although that may change as we go from warm weather to the hot dog days of summer, we'll see...

Anyway, sorry for the long post. Any insight/explanations appreciated, as I sure don't see the reasons for the discrepancies...

Cheers,

Tim

Tim,

The grounds don't get as hot as grass clippings because they have a lot less nitrogen. When I mixed nothing but leaves and UCG, I watered well, and the pile did get warm. Not hot, but warm. I did this in the fall, and by spring, I had the nicest batch of compost I've ever made, full of big fat worms.

The straw heats up because the sugars that were in the plant before it was cut and dried are still there. Adding moisture and UCG activates the decomposition, therefore releasing the sugars, heating up the pile.

Deanna

Tim, I suspect some of my posts are fodder for your comments on opinions versus field trials. I'm not sure what constitutes opinions and what constitutes field trials. I don't have a field, just a backyard bin, so I suppose that means I only have opinions. In my opinion, my compost got over 160F (about 71 degrees C) as measured by a compost thermometer. My opinionated compost bin was filled mostly with UCG, leaves and shredded paper. In my bin, I don't just layer, I mix. Maybe that's the difference.

Well, my results are definitely more in line with what Deanna is getting (ie. warmish at best).

bpgreen - you originally said your compost bin was filled only with leaves and UCGs, but now you're including shredded newspaper in the mix. Perhaps that's what's making the difference. Or perhaps the leaves you're using break down easier than shredded maple leaves. Forgive me if I sounded a little harsh, but I'd really like to get to the bottom of this - I can get large quantities of both UCGs and leaves, and if I can get this combo to heat up properly I'll be starting a production line :o)

And Deanna, I'm not entirely convinced that you made hot compost with your leaves and UCGs. But I have seen first hand that worms really invade a big pile of shredded leaves, and I hear they like UCGs as well (although they wouldn't touch my pure UCG pile with a ten foot pole!). I've started a worm bin with that combination, so we'll see what the next few months bring.

I also wonder if UCGs are somewhat sterile due to the coffee brewing process, and might act more "normally" if innoculated with some active compost...

Cheers,

Tim

If you reread my original post, you'll see that I said I get better results when I mix the UCG with "shredded paper, leaves, etc."

In a later post, I did mention mixing them with leaves only and reaching 160F.

So, I guess I need to clarify. I've mixed UCG with leaves and gotten hot compost. I've mixed UCG with leaves and shredded paper and gotten hot compost. I've mixed UCG with leaves, shredded paper and garden waste and gotten hot compost. About the only thing I've never added to the compost is grass clippings since I mulch mow.

I'm not sure what we're doing differently that your compost won't heat, but I can get to 160F with just UCG and leaves.

So far this year, due to an overabundance of leaves from last fall, I haven't added any shredded paper. The only paper that has gone would be the coffee filters (which I just dump in whole).

I'm on my second batch. One batch got to about 140F for a while before cooling. I started the current batch just over a week ago and it is up to 130F.

I think I'm not getting as much heat as last year because I'm trying too hard to use up the leaves and have too much C for the N. Even though it's not getting as hot as last year, it's still getting hot.

As for the worms, I don't pile grounds by themselves. Maybe it's a case of too much of a good thing? I think somebody else reported something similar a year or so ago. I spread them on the lawn, but try not to spread them too thickly because they can repel water when they dry (and drying is guaranteed in desert conditions). I have a lot of worms in my lawn.

I use my compost on the lawn, so I sift it through 1/4 in hardware cloth (much finer than I realized, next time, I'll use 1/2 in)). So every new batch gets some of the old batch to start with. I don't know if that aids in getting it to heat up but I think not. I started last spring by completely emptying the contents of the bin and had hot compost all last year. When I've dumped UCG on the garden, I've seen some pretty funky looking mold grow (but mold is not what generates heat in the compost).

I wish I could give you the "right" ratio of UCG to leaves, but I don't measure. I add some of one, then some of the other, watering every once in a while. If I'm being really lazy, I just dump bags of each in whole (but the leaves really tend to clump and stay dry with that approach). Actually, I've been taking this approach a lot this year, which may account for too much C and explain the lower (although not low) temps this year.

Once I get part of a bin started, if it's not heating up, I add more UCG or water it. If it's stinking, I add more leaves (or shredded paper or shredded wood if leaves are in short supply). I also mix it up a bit for either problem, since it could be going anaerobic.

As Deanna pointed out, UCG are much lower in N than grass clippings, so if you're using UCG in the same proportion to leaves as you would grass clippings, you won't see as much ehat. It could be that you've just got too many leaves for the amount of UCG (I'm pretty sure that's why I'm seeing lower temps this year).

maryann, if your pile is dry, that's why it's not heating up or attracting worms. Worms like an environment that's wetter than the usual compost pile. Composting bacteria need lots of moisture to work.

I just emptied a silver bag of UCG that I'd been storing for months. It was green with mold throughout, but dry.

Even with steady turning, forking, mixing, I have gotten pockets of UCG and filters that just seem to never break down or get digested by the many worms. However, the bulk of the UCG and filters do get turned into top-grade compost. It just takes time. One thing that seems to really speed the process is finely-ground egg shells. It gives them a source of calcium (which gets passed on to your plants) and grit in their digestive tracts to help them eat more and stay healthy. So your pile gets converted faster into compost and castings.

Thanks for the detailed post. Being as you're sure that UCG/leaves heat up, I took the temperature of my worm bin today, just to be safe (65L, about 17 US gallons). No heating at all, so my worms are safe (of course the bin is smaller than compost volume).

It must come down to ratios. I'd guess my UCG/leaf pile was about 60 - 75% leaves. Given that UCGs are fairly low in nitrogen, it would probably make more sense to go with 70 - 75% UCGs. Any idea (ballpark) what ratios you're using?

I still don't understand why pure UCGs don't heat up, but like yourself, I have used them as a mulch and had some funky looking molds lol

Alright, well I guess the bottom line is I'm going to have to experiment more next November with the leaves/UCGs, or try and get my hands on enough straw to make a UCGs/straw pile.

I made a sifter last week with 1/2" hardware cloth, and I'm wondering if I should have gone with 1". Haven't had a chance to use it yet (all my piles are cooking) but I hope to be able to use it by the first day of summer. Up until now I've spread it on as is, but I'm getting too many sticks/bones that need to go through again. I'd imagine it takes a while to sift with 1/4"! Probably be good for seedling mix though, if you start your own...

Cheers,

Tim

I've never done any measuring, but I'd say that I've been going with a little less than 50% UCG this year and not seeing as much heating. I think if I go with about 50% I get good heat, but as I think about it, I got the most heat in the summer. In the summer, I'm not allowed to spread them on the lawn due to smell, and I don't have as many leaves, so I probably had more than 50% UCG

I think the reason pure UCG don't heat up is that they are too compressed and don't allow air to circulate.

I don't spend a lot of time sifting. I put a shovel of compost in the sifter, shake it 10-15 times and toss what remains in a bucket. What ends up on the ground is very fine, so I'm pretty sure 1/2 inch would work well, too. I never sifted when I put it on the garden, but I (ok, my wife) found unsifted compost to be too unsightly on the front lawn.

I use a nursery flat as a sifter -- the kind with smaller holes. When the UCG aren't moldy, I also sift them into the compost bin and break up the hockey pucks. When I put them in as hockey pucks, they're still hockey pucks 3 months later.

I take those silver bags from Starbucks and drop them a few times on my driveway and most of the hockey pucks are broken up, so I don't have to sift. This works best if the bags are tightly sealed. :-)

I still sift sometimes when I am putting it on my lawn.

I don't sift compost when I put it on the lawn because, even with very small lawns, it would take forever. However, after that last time, the lawn maintanance crew (DH) reports the mower getting jammed with sticks, so I better either use better, bagged compost or sift.