I agree, the sun and maybe plastic as well are probably responsible for minimal if any, temperature rises. The heat comes from the breakdown of the materials. Interestingly, about 130F is the highest one should go. I used to be pleased with core temp of 160F, but finally realized that beyond 130F the breakdown process goes slower, not faster. Of course having a core of 160F is not the end of the world -- it means 80 or 90% of the pile is below that temperature.

But the compost thermometer is a good idea. Few people can judge exactly how hot the core of their pile is; and if the temp is rising or falling. I only put fish part in the core of my piles when the core is 130F or higher.

Unfortuntaly, after all day in a hot sun the temp did not get back to 140. This afternoon it is under 120. So, I think it was not the heat of the sun. Normally that the fresh coffee grounds create heat but, it doesn't seem to last very long.

I found my compost thermometer invaluable for learning to get my humanure heap up to temperature. I'm not too bothered about how hot or otherwise the other heaps get, but I like to ensure that humanure is well and truly cooked. I also like to be able to demonstrate to people how hot it gets so they are more confident about setting their own systems up safely, and one look at the temperature usually satisfies them.

I just stick my hand into the pile up to the elbow and depending on how many seconds I can keep it in there determines how hot my pile is.

I used to use a long copper bar and had it shoved into the side of a large bin. Pulled it out to test and if we couldn't hold our hand on it for more than a few seconds we knew it was pretty darn hot.

Use a thermometer now for record keeping but the bar was fun.

Lloyd

The temp is way down to only 90 degress. I know the only way I can make it really hot again is to get more starbucks grounds and add more kellogs amend and remix it. Maybe a compost thermometer has some drawbacks?

I don't long I would need to keep the temp up to kill weed seeds, but my guess is I am not hot enough to do that. I normally get a lot of weed right after applying compost to the soil. But, not every time do I get weeds, since I really try to keep weed seeds out of the bin. Sometimes the weed seeds are picked up with some of the native soil that I may get from racking up leaves. But, it is easy to remove those weeds as soon as they germinate. The compost is easy to weed.

I am seeing so much finished compost so quickly that I should remove from the bin when the temp is really high. But, my back needs more rest.

I used one for awhile, but once I got the hang of composting in my local conditions with the materials I had available, I got out of the habit of using it. It was not a completely useless novelty, but over the long term I'm just a more casual composter.

Tropical, can you get your hands on any grass clippings? I know that seems to stimulate my pile and then when I compensate with browns the temps tend to cool down a bit

tox, I have also stopped using my thermometer for the most part. I think that Lloyd's idea of using a metal rod makes a lot of sense. You can leave a metal rod in the compost pile and it will be ok, but a thermometer wouldn't last long if left outside. Copper and brass conduct heat very nicely, especially at the temperatures we are talking about, but a rebar rod would work well, too.

For people starting out with composting, use of a thermometer is helpful while you learn what works. Once you get the hang of composting, use of a thermometer seems to become less important.

I now use my thermometers when I am researching or experimenting, or to gauge soil temperatures to know when to plant.

Factoid; two years ago I used a flail shredder to macerate a large (10 yard?) pile of freshly fallen leaves. No grass to speak of, just leaves. The shredded leaves heated up right away. Leaves are considered a C source in the C:N equation, so I was not expecting that to happen. I grabbed my thermometer and checked it. If I am remembering correctly, the pile reached 140 degrees. I think the fact that the leaves had just fallen was part of the reason they heated up.

Due to this thread and Amazon Prime, I bought a compost thermometer last night.

Not really, you put the compost thermometer in for five minutes and then take it out. I once forgot it over night, but it was not harmed.

I leave my compost thermometer out all summer, only bringing it in once the temps start dropping below freezing. It's lasted 5 years so far, and I don't think it's about to break yet.

I've used a two-foot compost thermometer for about five years. In the past, I used all kinds of devices to estimate compost heat. It's a daily ritual for me to check on compost temps and, when a teaching occasion arises, it's convenient to show neighbors and friends how hot composting works.

My thermometer stays in the compost year round. My three pallet bins have hoop covers to protect the compost so neither the thermometer, nor the compost, is exposed directly to rain or snow.

Compost happens, whether you have a thermometer or not. I think some people obsess too much over their compost piles. If the, nearly, right mix is tossed together with just enough and not too much moisture the bacteria will get busy and go to work. As they work they will generate heat, not the sun, and if there is enough Nitrogen in the mix different bacteria at different times (thermophilic) will be at work resulting in the different temperatures. However, the bacteria that work best at 70 drgrees will, eventually, digest your material just as well as those that work best at 140 degrees would.
Put you mix together and kind of watch it but don't get overly obssessive about what is going on in there because it will, eventually, sooner or later, become finished compost.

Sorry Kimmsr, but it is human nature to fuss over things like this. If I can finish a compost pile in three or four months rather than a year, all the better.

My lot is only 1/4 acre, and only in one quarter of the back yard do I have soil that gets enough sun to grow tomatoes, peppers, onions, lettuce and spinach. I'd like to increase my garden space by cutting down my neighbors trees, but that seems to be frowned upon.

When you grow tomatoes in the same spot year after year; one needs a lot of compost to use as mulch in a attempt to keep the wilts and blights away. I've already pulled three tomatoes out with early blight.

I suspect that some posters with a layed-back approach to composting have a large yard or live out in the country. I never have enough compost for the whole year. My two large compost piles are fussed over and sometimes daily have their core temp measured.

I agree, a fast turn around makes better compost and is there you space for all the compost you are waiting on. You can end up with like 27 piles. I want better, faster, more volume compost.

I measure the temp daily. My daughter and I do it. She loves spending the time with me. This is our "thing" so daily fussing is a good thing.

I'm pretty casual, I'll have to look into the copper pipe though. But my piles back up to the alley, so hopefully the copper won't get scavenged...

..
"I never have enough compost for the whole year. "

Anyone here ever have enough compost?
..

:-]

Hi,

So when should you turn and when should you leave it alone? I am trying to figure out how a compost thermometer will help me speed up the process.

Thanks.

Once it has heated up properly, you can turn the pile when the temp has dropped, to get the outside of the pile on the inside and provide more food for the bugs to digest.

Knowing the temperature can also be useful if the temperature gets too high. In some cases, I know I'm going to have heat issues (temps greater than 160ish) so I monitor the temperatures more closely and turn more frequently to try and keep it in the 140-150 range. Some piles are just in that 140-150 range without much intervention so I don't have to spend time/effort on them. Temperatures can be a good indicator as to the health of a pile.

Lloyd

Thank you 2 for the replies. Isn't it better for the temperature to be as high as possible so that the materials disintegrate and sanitize faster?

Mine can not get too hot. I don't use starbucks coffee as much as I should. If the pile is kind of wet, it won't get too hot. Sometimes if the pile is dry and hot it could catch on fire, but that is very unlikely to happen. More heat kills more weed seeds and other bad things. If you though the pile was too dry and hot you could water it down so it won't catch fire, otherwise it won't be a problem.

Anything much above 160F will begin to reduce the effectiveness of the pile.

From Cornell...

"Because temperatures over about 65ðC kill many forms of microbes and limit the rate of decomposition, compost managers use aeration and mixing to keep the temperature below this point."

Lloyd

65C = 149F for us non-metric yanks. At least according to a google site.

When someone writes their backyard pile has a core temp of 165F that is a long way from saying their whole pile got up to 165F. What they probably mean is that on one or more days they had a core temp of 165F early in the piles life cycle. Assuming a proper mix and reasonable care; with each turn, mix, and watering; the pile will reach a lower core temp. So with a large 6'x8'x24" high pile, maybe 10% got to 160F, 40% got to between 110 and 160F, and the rest reached a high of only ambient temp to 110F. Just guesses on the percentages.

So instead of having a 'whole' hot compost pile, you have a mix of hot, warm and cold compost. Not the worst thing.