Hot Composting Made Simple

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Curing compost made using hot composting methods

When spent plants, weeds and kitchen wastes end up together in a compost pile, they will eventually decompose into compost. Cold compost is left alone to do its thing, which requires no labour but does not give first-rate results. Hot compost is a managed process that produces crumbly black gold better than anything you can buy in bags, and making it can be great fun! Late summer is an ideal time to develop your hot composting skills, because you probably have plenty of material on hand, and warm temperatures will help the process along by limiting temperature loss from overnight cooling.

Hot composting produces greater volume than cold composting, hot compost contains far fewer weed seeds, and it is much richer in substances that promote plant growth. Besides being good for your garden, hot composting is good for you, too. Making a batch takes about three weeks, and every few days you will get a full body workout forking and turning your smouldering compost, which is way more fun than going to the gym.

Hot Composting Basics

When putting together a no-frills compost pile, most gardeners try to make layers of bulky materials (leaves, old mulches, dead plants) and high-energy green stuff like kitchen waste, or perhaps chicken manure or processed pellets. With hot composting, you mix the materials instead of layering them, and you try to work with smaller pieces, too. I have the most success combining half-rotted weeds and plants that have been piling up all summer with the contents of my stationary composter, that dungeon of kitchen waste, and then tweaking the mix with fresh green grass clippings or shredded comfrey leaves. You want a rich mix, so this is a great time to clear the freezer of things you will never eat, which often make great additions to hot compost.

A metal stake in the middle of a hot composting pile can serve as a rustic heat gauge and aerator

Don’t worry about getting a complete mix the day you build your pile, because hot compost is forked and turned again and again. Go for building a sizeable heap instead, because large heaps heat up better than small ones. A hot composting project that starts out at least 3 feet (1 metre) tall and wide will usually give good results. A metal stake installed in the middle of a new hot composting project can serve as a rustic heat gauge you can feel with your hand, plus you can wiggle it to aerate the pile.

How and When to Turn a Hot Compost Pile

Once a hot heap is put together it is best to leave it alone for four days. This allows time for moisture to equalise while colonies of beneficial bacteria are becoming established. It can be hard to wait, but patience has its rewards. After four days I usually detect significant pockets of heat as I chop through the pile with a hoe, which is always exciting. Then I fork the material back into a pile, and cover it with a tarp (or the top section of my stationary composter) to keep out rain.

Turning a hot compost pile

The protected heap is mixed and turned every two to three days for two weeks, with noticeable heat or even steam evident through the first three turnings. You can use a thermometer if you like, which is the most accurate way to see if your compost pile has hit the magic numbers, which range between 130-140°F (55-63°C). Or, simply use your hand. If you can’t hold your fist in the mix for more than a few seconds, the heap has hit the ideal temperature range for its transition to top-quality compost. White, ash-like remains on bits of plant material in the heap are further evidence that your hot composting project is going well.

Curing Compost

Expect the temperature to drop in your hot compost after a week or so, but continue to aerate the mix every few days for another week. Active decomposition is nearly complete by this point, but the compost will improve even more when given time to cure. I cure mine in buckets and empty flowerpots kept in a spot sheltered from rain, or you could simply cover the heap for a few weeks. Allowing hot compost to mellow for a month after it is done allows time for the microbes in the mix to stabilise, and the texture of the mixture relaxes, too. It becomes dark and crumbly, agreeable to sniff and a pleasure to use. Better make as much as you can, because it runs out fast.

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Show Comments


"I appreciate your article. My problem is my compost smells musty. I have a tumbler composter that i turn every day. Its warm but not hot. I've had hot compost before, so i know what it is. Just don't know how to get it again. Any advise you can give would be greatly appreciated. Blessings Faith"
Faith on Monday 22 August 2016
"Faith, it's not exactly a sustainable fix, but if you put a small bag of cheap dry dog food in with the slow material in your compost tumbler, it should heat up within a day. It's mostly corn meal with protein added, so it's surge of nitrogen. "
Barbara Pleasant on Friday 26 August 2016
"I have been using hot compost in India now for two years - for me it was the only way I was ensured that they were no chemicals from newspaper or leaves, etc. I even processed the earth thought is to ensure it was not contaminated. I make my bed directly over extremely poor soil. The results are amazing from the beginning but 6 months down the line they were spectacular. "
Claude (Naya Kisan) on Sunday 28 August 2016
"I have been searching for articles on a composite pile and came across your blog, what a fantastic blog! And I liked the way how you had explained the making of hot compost with clear images . Thanks for sharing."
Jane Cristina on Thursday 8 September 2016
"I love it. I will use it"
Mwangupiri Samuel Ngosi on Friday 14 October 2016
" I dig a hole in the ground, chuck in grass cuttings, coffee grounds, cover it with soil, then cut the grass again about a week later, chuck that in plus any green stalks, then the coffee grounds (I sing the paper filters in as well) I have got during the week, then just cover that with soil Been doing this since I cut my grass first time back in March I have a couple of mounds now, not very high, but about 18 inches-2 feet deep I don't know if what I am doing is any good, but next year, I'll be digging it all in with a digger, leave it a week maybe a month then plant out some spuds, carrots, beetroot, maybe cabbages I will have the area under cover over the winter (I used to have chickens on the area, its the covers I used to protect them from the weather) First time doing it so I have no idea how it will turn out"
Derrick on Sunday 3 September 2017
"Thanks for sharing"
christine aoanan on Wednesday 13 September 2017
"Thank you for this. I am experimenting soon with buckets, with an eye to asdisting yhe poorer neighbours in our area to recycle and create veg gardens - Alexandra is a very poor area and the more education the better! My question is: for folks in shacks and very small areas, what is the minimum size to use for hot composting? It needs to be lidded buckets because the owls have all been chased away and thus rats need to be excluded. Thank you in advance"
Tessa Silberbauer on Saturday 27 October 2018
"Tessa, thanks for your good work helping create more gardens. I suggest looking at a keyhole garden design, using a closed pail for the composting container. There are lots of images on the web. Good luck!"
Barbara Pleasant on Monday 29 October 2018
"I have put all my grass cuttings, egg shells, coffee grounds in a lidded dustbin, I have used garotta (it’s supposed to help with the rotting process) The lid is quite tight fitting, so I don’t know if this will be any good Do I turn it upside down? In the hope that worms and bugs can get to it or just leave it the way it is ?"
Derrick on Monday 29 October 2018
"Barbara, thank you: sometimes one just needs the correct jargon :) I will use those terms and probably get *much* more informative results!"
Tessa on Tuesday 30 October 2018
"Hello, thanks for helping me with my quest to be self sufficient on the compost front. I mulch my veg plot and the garden borders so I need a lot. I have bought in the last couple of years my garden didn't generate enough material. I now augment with material brought from elsewhere. Latest heap was built last Friday with fresh horse muck, spent hops and cardboard, thin layers of each till full. Daily temperature checks were 29°c, 45°c, 53°c and 56°c this evening. I'll turn it tomorrow (or maybe this evening if I'm feeling impatient). This is my 3rd batch made this way. Much much faster and bigger volumes than gradually adding stuff to a cold heap."
@cavershamjj on Tuesday 30 October 2018
"Derrick, the only thing missing may be air, which is normally provided by holes made in the sides of the composting container, as well as at the surface. In a closed container, you can cut cardboard bathroom tissue rolls into thirds, and incorporate them into the mix. "
Barbara Pleasant on Wednesday 31 October 2018
"Cavershamjj, I am jealous."
Barbara Pleasant on Wednesday 31 October 2018
"Don't really want to cut holes in the bin, (I might use it for other things later) so I might just turn the bin over, let the works and bugs get to work on it over the winter (its a plastic dustbin) I guess I'll dig it in about March April when hopefully the weather will be warmer I have also dug a trench, filled it with cuttings, dead leaves and put a covering of soil over it, I have no idea how that will turn out, but something must happen to it, I hope"
Derrick on Wednesday 31 October 2018
"Great information"
Mary on Monday 14 January 2019
"Hi Barbara, Thanks for the great info!. I'm from Chile, and here with some extremely waste-contaminated zones we're trying to apply this method by educating people to generate their own composter bin. I got one question: How large needs to be the compost pile?, because in some scenarios we got very small piles, that don't get hot at all. Thanks for the info!, Cheers,"
Guillermo on Wednesday 11 September 2019
"Guillermo, it is okay for compost not to heat up, and small piles often cannot retain even small amounts of heat. Direct burial of kitchen waste is always an option, or you can look at the central pit or cone used in keyhole gardens. Good luck with your fine efforts!"
Barbara Pleasant on Friday 13 September 2019
"Hi All, I cannot agree with your statements that live organisms are present in the hot compost heap at 65 degrees celcius. The fastest and best method of breaking down organic material is with BACTERIA. The ONLY animals on the planet that PRODUCE BACTERIA are COMPOST WORMS. We only need to look at how Nature works to see what are the best ways to create soil. Once the organic matter has been heated to such high temperatures, the material is DEAD, there is no nutritional value whatsoever in this material and plants cannot get nutrition from DEAD, LIFELESS material. The whole idea of creating compost is to provide NUTRITION for your plants. The best nutrition for your plants is PLANT SOLUBLE, IMMEDIATELY AVAILABLE nutrients. By far the MOST effective, quickest and best way to make NUTRITIONAL PLANT FOOD is by WORM COMPOSTING."
Robert Taylor on Friday 17 December 2021
"I put together a winter hot / drunken composting bag layered with dry leaves that were a little damp from rain, old soil mixed with basic food scraps (veggies, coffee grounds, eggshells), chicken manure mixed in mulch bedding, and a small amount of extra (slow) compost I had on hand from early on in the year. This was on 12/11. It all went into two 42-gallon, 3-mil contractor bags (store I was at didn't have the 55-gallon size). So, basically, a double-layer of bags. Fashioned a ~30" long air tube from 1/2" hardware cloth with cutting snips, zip ties, and paint strainer pieces, ~3" in diameter. Poured the recommended tonic with some extra hot water throughout the layering process until the bag was filled about 18"x18"x18". I would have added more material, but I had to move the bag and the weight was a struggle at that size. Was hoping to get to 24" high at least. Tied up the 1st bag around the pipe and "half hooded" the air pipe w/ the 2nd bag (in case of too much rain) with half of the front vertical part of the pipe still exposed to air. I inserted ~2"X~6"x~12" pieces of foam "bricks" wrapped with cardboard and secured with making tape on the inside in the surround of the 2 bags to create an air pocket (although I should have done it DURING the filling vs. after). Then I set the bag on a medium-sized piece of folded cardboard (3 layers) that was placed inside a thick plastic shopping bag. An extra as a buffer against the cold ground. On a clear day, the sun does hit the bag straight on for at least 2 solid hours. On day 5 I felt the outside of the bag and was pretty surprised that it felt warm since I didn't have the "regulation amount" of recommended contents. I don't own a composting thermometer, so I bought a glass candy thermometer for $5 at the local hardware/home store. Not wanting to disrupt the soil I tied and eased it down into the air tube to at least measure the ambient air temp. It clocked in at 100 degrees F. I've measured it several times since at different periods of the day. It's still holding at 100F. Day 6 (today) was 30 degrees F in the early AM and after the day's high of 39 degrees F. We're just past mid-December now in Michigan's zone 6A. I would imagine the compost material itself is at a higher temp than 100F at this point. Just thought I'd share the interesting results so far. Creating compost was 2ndary to this little experiment. I actually wanted to see if this would turn out to be a functional independent "heat reactor" that could be placed up against a couple of secret feral cat houses by my job to provide a little extra heat and insulation during low winter temps. Any resulting compost would be a gardening bonus for spring 2022. Especially since I will have to cycle these bags and replace them with new ones every few weeks. The upcoming overnight lows will be in the 20'sF for the rest of the week, so we will see. I sourced my fresh chicken manure on Craigslist from a backyard chicken person since I live in an apartment. Figured that would be best since it's notorious to run hot under the right conditions."
WLP on Saturday 18 December 2021
"I can achieve the hot compost temps in my three sided bins made with old pallets with chicken wire lining. We have an issue with Asian Jumping worms here in New Hampshire USA. The over 100F temps will kill them, but as the piles cool, they make their way back in. I am thinking that I should somehow “line” the hot composting bin with a permeable barrier to keep out the Asian Jumping worms, or transferring hot compost to a barrel to finish and then store sealed in a drum or container. Any and all suggestions welcome."
Chuck Stock on Saturday 18 June 2022

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