cynthia_h
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Slow-to-Decompose Ingredients

We turned the compost pile this weekend. I'm still screening the more-or-less finished compost, and a few ingredients are proving surprisingly difficult to "encourage" to decompose. In other words, I'm returning them to the bin completely unfazed by their journey.

No observable changes:

* peach/nectarine/apricot/plum/pluot pits (some are at least 2 years old; others possibly older)
* raw peanut shells (I *know* these are 2 years old)
* timothy hay--acquired from rabbit rescue (6 months old)
* rabbit litter--acquired from rabbit rescue (6 months old)

The usual slow-to-change stuff:

* avocado skins
* avocado pits
* corn cobs (usually 12-18 months, slow but continuous decomposition)

Pleasantly surprised by the decomposition of:

* 100% cotton quilting fabric
* dog hair (both clean and dirty)

Interestingly, mango pits are favored "beds" for the compost worms. The germ of each pit has been eaten, and the shell is being used as a nest by many, many worms.

Will update as I go through the rest of the 5-gallon buckets, screening through 1/2-inch (approx. 1 cm) hardware cloth.

Cynthia H.
USDA Zone 9, Sunset Zone 17

P.S. DH and I have decided NOT to compost future peach/nectarine pits.

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smokensqueal
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Good information. As far as the peach pit I found some from what I assume was the first few months of composting last year so they are just over a year old. They looked perfect but one out of the 3 broke up quite nicely after a small tap of a rock. So maybe that will speed things up a bit. The other 2 were still solid. I'm not sure how much the pits contribute to the bin but I know that the fruit that was left on them is now clearly gone. I also observed the same thing with the peanut shells. What's up with that?

I found that our corn cobs looked perfect after a year but what I also did notice that if you find some that look perfect doesn't mean they won't crumble when you squeaze them a bit. I'm not quite sure how old they need to be but I found some that I thought was about 8 months old and they crumbled into little pieces with very little effort.

To add to your list of not much change I would have to say dryer lint. I added some a long time ago and I just found it the other day. I thought most if all of it was cotton but I guess there was some other stuff in it. I no longer add that to my compost.

TZ -OH6
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Most woody plant material is made up of an intricate mix called lignocelulose [Lignin+cellulose+hemicellulose]. The celuloses can be broken down completely into sugar and used as food by microbes, but the lingin is not used by microbess, and just gets in the way. Only a very few microbes can break it down to get at the celluloses, so it stays around a long time. The breakdown fragments are chemical humus, and can stay in the soil for hundreds of years. Lignin is very hard and accounts for the hardness of gritty pear stone cells, and hard fruit pits. Peanut shells are exceptionally high in lignin, so they breakdown much slower than wood, but contribute more to humus formation.

cynthia_h
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Update from last August. DH and I turned the BioStack last week, and it was turned at least once, in December, and possibly in October as well.

Still no observable changes:

* peach/nectarine/apricot/plum/pluot pits (some are at least 2.5 years old; others possibly older)
* raw peanut shells (I *know* these are 2.5 years old)
* timothy hay--acquired from rabbit rescue (12 months old)

Decomposed after 9 to 12 months:

* rabbit litter--acquired from rabbit rescue

The following "usual slow-to-change stuff" was no longer visible as distinct ingredients:

* avocado skins
* avocado pits
* corn cobs (took 18-24 months of slow but continuous decomposition)

Mine is a cool-to-cold compost pile in an enclosed Biostack bin with part sun / part shade. I'm unable, physically, to turn it as often as I'd like, so it's turned somewhere between monthly and quarterly and put through a 1/2-inch hardware screen. I also remove all the compost worms I can so they can keep working for me in the compost. I have earthworms to work the dirt! :) (They came out en masse during the heavy rains, so I know they're there.)

Cynthia

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rainbowgardener
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I gave up on putting avocado shells (skins) in my compost. They appear to be indistructible. Another thing I no longer compost is ivy I pull out of the garden. I've had it in compost piles for two years and it still looks fresh and green. Corn cobs in my pile work pretty well. The first time I turn the pile, when they've been in there a few months they look pretty intact, but usually can be broken open easily at that point. Often when I break them open, they are full of earthworms inside. Put the broken pieces back in the pile and next time it's turned, they are gone We used to have lot of corn cobs because we fed corn to the squirrels (helps keep them away from the birdfeeders). We saved them in a trash can and ground them up separately. Makes good mulch. A lot of the stuff that doesn't break down well (like the old tomato vines, the dead stems of kind of tough or woody flowers, and the avocado shells) I save in a separate pile. Once or twice a year I get out my baby chipper shredder (it's a small lightweight version, not one of the kind you can run large branches through) and run that stuff through. Then it can go in the compost and breaks down beautifully.

Charlie MV
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We hot compost and use a chipper. I haven't found anything that wasn't garden ready this year. Most piles were cooked down in a month. We left them and added leaves and rye grass through winter and What we're spreading now is rich, black and fine. I turned the hot mix anywhere from daily to every few days. after a month I turned each pile once or twice over the winter. The shredder didn't like pumpkin rinds unless I cut them in shreds but every thing else succumbed without protest.

rot
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..
Most of the problem ingredients mentioned are made to be resist the elements. Skins, shells, seeds and so on need to survive rot to protect the fruit and germ of the seed.

Try composting bark some time.

If you think you or a cow might have a hard time digesting it, your compost probably won't do much better.

Composting is a function of surface area. Chipping and shredding magnifies the surface area so viola - it breaks down faster.

If the materials are too fine, ground to dust just for an extreme example, no air gets into the pile or bin and the process gets starved for oxygen.

two cents
..

sweet thunder
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When I moved here I thought my days of raking were over, since I have no deciduous trees on my property. I had no idea how much debris one redwood tree could produce!
Those needles take forever to break down.
I know, redwood is full of tannins and generally resistant to rot, hence its usefulness as a building material, but it still boggles my mind.

Another thing I've noticed to be compost-resistant are whole cranberries.

Gerrie
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Last year I put a lot of my compostable kitchen waste into the food processor first. Works great on pulse, but be careful not to liquify everything. We don't have a chipper but that sounds wonderful.

MagnoliaMan
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I screen the stuff to get chunks, hidden plastics, etc. out of my compost. After three years I still have the stems from hardy pampasgrass (Erianthus ravanae) that refuse to rot. I have had trouble with tomato stems and pepper stems. By the way, I can see how whole cranberries wouldn't give in - acid reaction prevents micorrhizae from approaching!
Magnoliaman

Gerrie
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I thought we aren't supposed to put tomato vines in it because virus's can overwinter or survive the composting process. I have a lot to learn.

My clumpy grasses with roots attached did not decompose either.

Has anyone ever tried hot water on the pile when you moisten it?

rot
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... 
I wouldn't be surprised if you aren't supposed to compost vines. You aren't supposed to compost stuff from your rose bushes either in case they were diseased in some some way.

I compost all that stuff. I have to figure that a compost pile of a decent mix producing decent temperatures is going to get rid of all that bad stuff anyways. I can't imagine if you are following the 10 percent rule that anything could go that far wrong.

Maybe I'm just living on the ragged edge of disaster.

two cents
... 

The Helpful Gardener
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Hard to compost means one thing; high carbon content (cedar shingles have 1000 to 1 C/N ratio)

Green to browns, or carbon to nitrogen ratios, is the crux of composting...

There is a tendency for herbaceous plants to like bacterial composts, which focus a little more on nitrogen, and for trees and shrubs to like carboniferous fungal composts, with more browns in it. The former tends to be bacterial and a little sweeter, and the latter more fungal and a little acidic. As for whether acid becomes fungal or fungal becomes acid, or the like question as to the bacterial/ base connection, it's like the chicken and the egg. Does chemistry drive biology, or does biology drive chemistry?

:?:

We can dig deeper here if you like...if your head hurts already...RUN!

HG

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smokensqueal
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Like RG said. Vines just don't seem to decompose. I added some I think Ivy vines in the compost last year and even through the middle where my pile gets fairly warm (not sure if it's considered "hot" I don't have a thermometer) it didn't seem to phase them much. I would like to get a chipper but I have to convince the wife that I "need" it and I would have to find room for it in the garage. :cry:

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rainbowgardener
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My chipper is a small light weight model, not fit for chewing through big branches or anything, but great for reducing all the tough vines and woody plants to readily compostable ingredients. I bought it used from ebay for quite cheap and have had good results with it for several years now....

rot
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... 
I won't compost english ivy. The sucker is hard to kill and an invasive. I've had small amounts but I'll let it desiccate in the sun for days or weeks before I chuck it in the bin. Hate that stuff.

Got an old violent chipper off of craigslist for 40 bucks plus another hundred for service. I'll be happy if I get a couple of years worth of chewing sticks.

I'm kind of curious about this fungal versus bacterial thing. It seems when I get mushrooms in my cold bins they reduce a lot faster. Does that mean I will end up less compost? Different nutrients in the end product?

Will fungus impede the bacteria or the converse?

Will fungus impede critters like the worms?

If I'm chipping sticks then I want fungus if I got this right. I seem to end up with a lot of sticks so this would be a really good thing.

Does a fungal environment bring any benefit to reducing pathogens?
... 



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