hot, fast composting temperatures

I'm in the middle of an 18 day compost. It's been turned 4 times so far, but more like every 3 days than every 2. The start was a good hot temp but too much nitrogen (smelly, white powder) so I added a bit of peastraw. That's settled down and it's looking really good with no smell now, but the temperature has dropped and isn't coming up between turns. I can't remember what it's supposed to do in the last week of turning. Should I still be getting high temperatures all the way through?

At the start it was 60 - 65C/140 - 150F. In the past few days it's 40 - 50C/105 - 120F. It got turned yesterday, today it's 40C/105F. Should I add some activator in the next turn? I won't have manure for that one, but could get some for the one after. I have fresh comfrey, urine, some really old liquid compost (probably comfrey but can't remember) etc.

Hi Rose. My suspicion is it has burned thru the nitrogen, and since you've been turning frequently, I don't think a lack of oxygen is the issue. I bet if you add more nitrogen containing stuff, it'll heat right back up.

Probably nitrogen, and also confirm the moisture levels are still good, "wrung out sponge" I think was the term I've read for the target moisture level.

I figured that is what happened too. My questions is more about how important it is to keep the temp up to 55 - 65C throughout the whole process. It's sitting 40 - 50C at the moment. I will add some grass clippings in the next turn, but I am still curious if it matters. Does the lower temperature mean it will take longer, or is it going to fundamentally change how the composting happens?

Is that what your really want such a high temperature? I don't know.

The lower temperature does mean it'll take a little while longer. A lot of folks who compost strive to achieve a hot 140f+ at least for a few days, as it's those kind of temperatures that kill not just weed seeds but also pathogens that infect and cause disease in plants. It is not necessary to maintain a very hot compost pile throughout the composting process.

Angelika Maier wrote:Is that what your really want such a high temperature? I don't know.

Yes, in the 18 day compost method (aka Berkeley method) you ideally want the temperatures between 55C and 65C. This is part of why the composting happens so fast (plus as James mentions, it kills seeds so you can put all sorts of things in it that you can't put into a cooler compost). I'm just not sure if I am meant to keep it that high all the way through the 18 days.

James Freyr wrote:It is not necessary to maintain a very hot compost pile throughout the composting process.

Are you talking about with the 18 day method James?

No, not referring to that method. I've heard about it, but I've never set out to compost with a goal of having finished compost in two and a half weeks. It sounds too good to be true to me, but also I've never tried it. I do compost, and I add kitchen scraps every couple days, the turd laden bedding from my chicken coop when I clean it, and other garden scraps and such, and I'll turn it whenever I get around to it. I really go about it in a casual way. I do have a thermometer and my compost piles do get over 150f, but it's short lived and they gradually decline until a few weeks later they maybe 80 or 90 degrees, until I dump the bedding from the chicken coop on top and it rains again. I'll actively add to a pile for a year, then let that pile sit for a another year, usually covered, with occasional turning every month or every other month, and two years from when I started a pile it's really nice looking stuff with small crumb structure and it smells good.

It definitely works. I just can't remember from last time how hot the temps were meant to stay over the whole 18 days (the composition and turning is what keeps the temperatures high). Was hoping there would be someone here who had done it a few times. Thanks though.