Reviving an old Thermophilic Compost

Thermophilic composting is the practice of breaking down biological waste with heat-loving bacteria.
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starr.m
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Any tips on REVIVING an old thermophilic compost pile?

We have a pile in the corner of your yard that we have been throwing leaves, grass clippings and yard waste into for 2 years. For various reasons, we haven't turned the pile for 2 years. Today I went out to explore what the state of the pile and it is mostly just a mass of grass clippings that have solidified together. I found a couple of earth worms, but not many other living creatures considering the size of the pile. I did see some white fungus here and there. I was wonder if I can pick axe out some of the mess and break it down, if I could get it started again and turn it into something useful? Would mixing it with leafs, a bit of straw, maybe some wood chips, a bit of partially decomposed food waste, and then turning it again regularly getting turn it into something useful again? Any other suggestions?
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Andrew
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It sounds like your pile is finished! Hold back a 5 gallon pail as inoculant for a new pile and start a fresh one.

The thermophilic process is generally complete after 18 months for the longest running piles and can be complete in as quick as 18-21 days if not composting any wood. So as you can see its quite a range.

The progression of a pile for me is:

- Build pile.
- Heat hits 55C/130F - turn
- Heat hits 65C/150F - wait 1-3 days and turn (turn immediately if it goes above 65C/150F)
- Heat hits 65C/150F - wait 1-3 days and turn (turn immediately if it goes above 65C/150F)
- Monitor pile, turn pile if temp exceeds 55C/130F.
- Allow pile to sit for up to 18 months monitoring temperature. It should hold 40-55C (104-130F) for this entire time. For how long? It depends on your pile, but regardless you are looking for a period of time that the bin holds a consistent temperature without fluctuation. For our piles this is 18 months.

If you are not working with manures, and are not concerned with weeds or seeds, you do not need the pile to reach 65C / 150F, you can skip this step and just get the pile to 55C / 130F and keep flipping until it holds this temp.

If temp drops or doesn't reach 55C / 130F you need more nitrogen or your pile is too wet.
Kristin
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Thanks Andrew. I’m in a similar situation however I don’t see any white fungus, but I have regular and red wiggler worms. It’s been a pile I’ve added on to for a couple of years, but I’m still finding some not broken down items (leaves, clumps of grass, woody stalks).

Yesterday I decided to try and hot compost it, so I’ve set up mesh fence in a circle and layered as best as possible, using some existing dirt in the pile, and leaves from the fall and a small amount of compost I had on hand. I’ve got a thermometer in it, and the temp is air temperature so far, but maybe I had too high of expectations for one day. It was moist but not soaking and I put a cover on it.

I did have chicken manure with wood shavings in it previously (over a year ago) and while it looks like most of that has broken down, I’m extra cautious because of that.

How long at this time of year will it take the pile to go hot? If it’s too low in nitrogen, can I try and relayer it once I have some grass clippings or another source?

Thanks!
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Andrew
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If there are worms in the pile, the compost is not finished, there is something of interest in there for them to eat. The key is that you are adding to this pile, and this is not how thermophilic compost is done. Even if a pile was hot at one point, once its cools down its no longer hot composting, its cold composting and this process can take several years.

Thermophilic piles are made, they heat up, and eventually they cool off. Before that happens generally the pile is turned two or three times to ensure that the outside of the pile ends up on the inside so that it can be hot enough to kill weed seeds and pathogens. You need all your ingredients for a hot compost pile up front, you don't keep adding materials.

For the home owner the best method I have found is to bokashi compost your food scraps through the fall and winter and save them up to use in the spring to make faster thermophilic piles or to start long running thermophilic piles to be available for next spring. Right now is an excellent time to make compost you want to have available for next year.

I am editing a video this morning on adding bokashi to a thermophilic pile that will hopefully make it out this week and it will demonstrate what I'm talking about.

A properly constructed hot compost pile is already warm (25c/80f) within 12h and is hot (60c/140f) within 72h (and can easily be made to get hot within 24h).

Grass works great to kick start a pile, but be careful it clumps, goes anaerobic and also heats up very quickly and then fizzles out.

Definitely join the Zoom Q+A on composting next week!
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