Hot composting and humanure

Having done a survey of the soil in our garden, one of my main aims has been to increase the biological and fungal activity in the soil. For this we will need loads, and loads of compost!

Hot composting

After some research, I decided that the quickest way of doing this would be to make a hot compost pile. Basically this involves making a normal compost heap, with lots of layers of high-nitrogen materials, mixed with high-carbon materials, then turning the heap every two days. This mixes the materials thoroughly, and aerates the pile, providing oxygen to the bacteria and helping to spread the fungal growth. Using this method, it should be possible to make a rough compost in 18 days.

My first heap was a great success. I used old sheep bedding, which has a high nitrogen content from all the urine, as well as some straw and poo. I mixed this with cut weeds from the garden, of which we have lots! I turned it regularly, watering it with urine if it dried out. The internal temperature rose rapidly to about 50ºC, then died off after a few days. The heat is a good indicator that there is lots of biological activity going on, and you can see the fungal growth in white strands passing through the heap. It was quite amazing, the heat from the compost was incredible, so hot you could barely touch it!

The pile did not decrease in volume at all, unlike a traditional compost heap, so we got a huge amount, about 2m², of rough compost. We used this mix to feed the garden and trees. One thing we noticed, was that where previously we’ve had a problem with ants climbing the trees and eating the fruit, the compost seems to have given the ants plenty to use at ground level, so they don’t seem to be bothering the trees so much.

Humanure

We’ve been storing our own poo, or humanure, for about a year now, so it’s worth reporting on what has happened with that. The humanure has been kept in plastic barrels, with a fine mesh on to keep thee flies out, and a loose lid to allow for air to enter. I’ve rolled the barrels regularly to mix up the contents.

Humanure barrel maturing
Humanure barrel maturing

After only a couple of months the humanure looked nice and decomposed, with no odour in the main body. However, after tipping some out to have a look, it seems that rolling the barrels hasn’t been sufficient to mix it up properly. While we’ve tried to separate out the urine into a separate container, some has gotten into the barrel and mixed with the soil at the bottom. This has created an evil–smelling lump of soggy soil at the bottom of the barrel. To get round this we will use straw at the bottom of the barrel instead of soil. We had also overfilled the barrels, making it harder to aerate the contents properly.

We’ve also had an issue with toilet paper – to add it to the barrel or not. While the paper will eventually decompose, it takes a lot longer. We’ve decided not to allow paper in the barrel, as when the barrel gets emptied out onto the compost heap it will be visible, and may lead to awkward questions from our Bulgarian neighbours, who already think we’re completely mad, what with our reed beds and mulching! Leaving the paper out makes it all a bit more discreet.

We’ve decided to mix our humanure with other materials in a hot compost pile. The high internal temperatures reached in these piles will ensure any pathogens are completely destroyed, and the resulting compost will be safe to use on all the garden.

Putting it all together

For my second hot compost heap I’ve gathered a lot more materials. I’ve got a pile of horse bedding from a friend’s stable, there’s still plenty of sheep manure to use, loads of weeds from the garden, straw and sawdust from the chickens, and our humanure. Having mixed this lot together I now have about 4m² of compost, with an internal temperature of about 65ºC. I’m not mixing this heap up as much, mainly because we don’t need in until later in the year, but also because I’ve hurt my elbow turning the first lot.

Hot compost pile
Hot compost pile

I am able to use the temperature and look of the pile to gauge what extra ingredients to add; if it’s too hot, add more carbon materials like straw or sawdust to reduce the nitrogen ratio. If it’s not hot enough, pee on it. The pile needs to be covered, both to prevent it drying out, and to stop it getting too wet from the rain. If it’s too wet the bacteria can’t breathe.

So, we now have 6m² of compost which we can use in the autumn to prepare the ground for next year’s plantings. We’ve been able to use materials which would normally take much longer to decompose, and we’ve got compost that has a huge amount of bacterial activity and fungal growth, which is ideal for trees and other plants around the garden. Early tests on our potato bed shows that adding the compost as a mulch has led to potato plants about 50% bigger than the ones without, but we’ve not yet assessed the crop yield from those beds.

  10 comments for “Hot composting and humanure

  1. Anonymous
    July 12, 2015 at 11:29 am

    I am surprised that you are using toilet paper. Don’t forget that in many areas of the world, people just have a wash. It’s more hygienic and reduces waste. Bidet, sink, little bowl of water and flanel next to the loo…. Sorry if this answer went a bit too far, but in the context I thought…😊

    • Julie
      July 12, 2015 at 11:38 am

      Interesting point, and very valid, but I think that would be too much for us and our guests!

  2. Alan & Julie
    July 12, 2015 at 11:32 am

    like the compost heap but the humanure,,,,,,,,,,, sorry thats like something from an Army commando survival course. ill stick to the horse manure method !!! love the blog all the same, great stuff, keep blogging

  3. Anonymous
    July 12, 2015 at 11:38 am

    I love what you guys are doing. At the risk of being forward, I am surprised that you are using toilet paper. Don’t forget, in many areas of the world, people wash. It’s more hygienic and produces less waste. Bidet, sink, a bowl of water and flanel next to the loo does the job… Thanks for the blog and keep the good work up.

  4. Anonymous
    July 12, 2015 at 11:40 am

    Oops, sorry, it posted twice, Juce

  5. Becca Churchill
    July 12, 2015 at 1:49 pm

    Hi Julie and Joe. Wonderful what you’re doing. I live off grid in Catalunya. I have a compost loo. I use olive cuttings mulched down to cover the waste. Both poo and wee go into the bucket – don’t seperate out – and then that goes into a concrete compost bin (1m x 1m) along with all my veg waste, garden cuttings etc. I built 2 bins side by side and after a year when the first bin was full I covered it and started the second.. Had a look recently at No 1 bin. The quantity has reduced drastically and the result is what looks and smells like wonderful crumbly compost. The heat out here is not a problem and during the height of summer what I put in is reduced to white, crumbly compost within days. My intention is to use the compost around my olive trees and veg. I know some people find this hard to accept but I don’t have any qualms as I believe that any pathogens that might have been present have been destroyed by the intense heat. And as is mentioned in the Humanure book (my bible!), if you’re a healthy human being with no known pathogens, not taking any meds etc it’s unlikely that there’s any need to worry. Many good wishes with your venture. Becca

    • Joe
      July 12, 2015 at 1:53 pm

      Hi Becca, thanks for stooping by! Does your concrete bin allow contact with the soil? I wondered if that was needed to encourage decomposition. It really is amazing how quickly everything stops looking like poo! The Humanure handbook is our bible too, but I thought for peace of mind for us and visitors (we have a lot of volunteers and guests) we’d go for a hot composting method to ensure pathogens are completely destroyed. Thank you for taking the time to comment, and wish you all the best with your own project 🙂 Joe

  6. July 12, 2015 at 9:46 pm

    Love to hear more people are getting into humanure. Just like to make a few points for people starting out.
    1) do not separate the solids from liquids. Urine accelerates the decomposing.
    2) Unless in an extreme hurry, turning the compost pile shouldn’t be ness. if you always use sawdust and straw/hay each time you empty the shit onto your compost pile.
    3) If poss. compost straight onto the land, the worms ect. help to decompose.
    4) If in a sensative area or near waterways, dig a small pond with rushes and stones to filter any leakage from your compost heap.
    5) Remember that he higher the temp. the better, this system is the most superior to any other used by local authorities, for killing harmful deseases/bacteria.

    Keep going and good luck everyone.xx

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