I'm impressed! A lot of people (even experienced composters apparently) don't understand that once material has gone through a tumbler it often requires curing to achieve a fully finished product.

We built our own curing bin for the material once it has completed the heat process in the tumblers. Used it a lot but lately we have just been emptying the tumblers into a curing windrow. Still use the curing bin, just not as much.

Lloyd

I havn't mastered link posting so I will just suggest looking at my recent post titled "Water repelant compost" for information that is very relevant to what you are asking.
Aside from those issues,here's how I handle a portion of my compost when at the stage you are speaking of. There is still a lot of "grazing"for worms so I put worms in the material without additional feeding and closly monitor moisture to keep it suitable for them. As it turns out, that action was what prevents the problem I experienced with commercial compost I had bought,albeit accidential.

Finished compost will not need "curing". If compost needs "curing" it is not finished and ready to use.
My compost stays in the bin it started in until it is finished.

Lloyd - Does it matter if the curing pile gets some air? Your set-up, with the tarp thrown over, seems like it would get minimal air. Is that okay, or do you turn the material on occasion?

Also, what if you (like me) sometimes forget the tarp and the pile gets rained on? I don't see drainage holes, but I gather than excess water would drip out the side. If I were to use a pre-made storage bin of some kind, I might want to drill drainage holes.

Klem - good point on the earthworms! I'll have to try that.

I use a laundry hamper (without a lid) that is approximately 25 inches high, 15 inches wide and has handles. I actually bought two and store the empty one outside the bin I'm using. It was an experiment to put compost that wasn't quite ready to use in and see what happened. The holes are 2 inch x 1 inch ovals. Lots of them. I bought the bins at Wal-Mart for about $8 each. They have held up well over the last two years. Both green, unobtrusive, and work great.

Wish I could post a photo, but can't seem to with this technology. I've seen them in the last 6 mos at W-M.
Sunny

motria - The bin is made out of galvanized steel sheets from a grain dryer. There are a billion tiny holes in them so LOTS of air can get in. Larger holes would just allow my compost to 'leak' out. As it is, there is some compost dust that escapes.

The tarp is purely for rain protection. I actually don't use a tarp anymore because we made a sliding top for the bin, I just don't have a picture of that.

As you know, air is super critical when the compost is heating, not so much for curing. The curing bin is utilized when the tumblers no longer heat up above 110F or so (the 110 is not carved in stone, IOW, it's flexible).

Lloyd

As much as I've read ad nauseum about compost and the composting process both on this forum and on various sites on the 'net I still don't know how to determine when compost will reach that magical state of 'finished'. Can anyone enlighten me? Once finished does it have a 'shelf life' or will it last forever in that state?

When my compost looks homogeneous, smells good, and without identifiable pieces I consider it finished enough to use as mulch. I try to adhere to the KISS principle in regard to both compost and RL.

I guess if I ever had too much compost I'd have to think about storing it but I never have what I consider enough.

"Finished" can be like beauty in that it is in the eye of the beholder. There are technical tests that can be used for determining the maturity of compost such as the Solvita system. One can also use the bag test and germination test as a guide.

If used solely for mulch, one doesn't even have to do any composting to use some materials. Different uses and timing may allow for usage of different levels of maturity compost. In a nutshell, when asked how mature compost has to be, I usually answer "it depends".

Further consumption of completely mature compost takes place ever so slowly, storing or worrying about the product 'disappearing' is not really an issue for most. The greatest volume loss takes place in the very beginning of the composting process. I've had finished, completely mature, compost sit in a pile for almost two years with no apparent loss of material. Sure there would be some further consumption, but it is not easily discernible.

Lloyd

Compost is finished when it is dark and crumbly and smells like good rich earth and the original material is not easily seen, distinguishable.
Compost, kept dry, can be stored for quite some time but compost stored for two years with little loss of material would concern me because that indicates the bacteria that digested the compost are not at work.

The topic line might have more accurately left out the word 'finished'. Finished, Completed, Stabilized, Curing, all words we use to talk about the latter stage of composting. The OP mentioned that they recognized that just because the heat had declined this did not mean that the composting was complete.

I like large-ish mesh bins for both hot and cold composting. They hold a lot, mine are low and easy to turn, can be moved, are cheap, do well in winter, and handle problematic ingredients well.

I would suspect that most people cognizant and knowledgeable about tumblers knew exactly what the OP was referring to with the phrase "post-tumbler "finished"".

Anything more than 1/2 inch mesh wire would not work for the vast majority of my 'post-tumbler' material because it would just leak out of the holes, especially once it was close to being fully matured.

As for anyone being concerned that there is little to nil shrinkage of fully matured compost, don't be. Mature compost is not digested nearly to the extent as the virgin materials. This 30 gallon container might shrink half an inch in a year and I suspect most of that would be settling as opposed to actual bacteria/fungal decomposition.

Lloyd

Beautiful pictures, Lloyd! I've never let my compost sit long enough to get to that mature phase, but I definitely recognize the post-tumbler look.

Thank you. I have to admit it was an accident. I got busy and never emptied the tumbler out for an extended period and that is how it came out. It's not really necessary to let compost get to that stage but people loved it so that is what I strive for now. I've given away probably close to fifty yards or so over the years between garden groups, community gardens or other various worthwhile projects such as the local Legion or Palliative Care fundraising and have never gotten anything but positive feedback.

Lloyd