I want to try turning human manure (humanure) into compost.

How much time does it take to become compost? Or how much time it takes the compost to become humus, ready to be used as a fertilizer? Maybe this is a better phrased question.

I live in Spain.

And what's the best carbon material to use? Straw (hay)? Sawdust? Autumn leaves?


3 Answers 3


The problem with composting crap is the possibility of contagion and parasite transfer.

Even if material is covered, it takes a lot of covering to block all the flies. Flies transfer bacteria at minimum, and smaller worm eggs aren't impossible.

However, if you want to do this, I would suggest doing it via a composting toilet. In your climate the Sunny John system should work quite well.


This is a system of solar assisted composting, with the crap screened from flies, and maintained at a high enough temperature that you can actually kill most pathogens.

Despite this, I would not use human compost on a veggie garden, but rather use it on the flowers.

In passing: Much of the nitrogen is in urine. Urine, unless you have a bladder infection is sterile. Sterile enough that if you have an injury in the bush, it's an acceptable substitute for clean water. It has enough stuff in it that it will grow a bacteria culture fairly soon, but you won't transfer pathogens from one person to antoher through pee. Go pee on the compost pile.

  • Parasite eggs and protozoa (such as toxoplasma gondii) can be found in urine. I suppose the chemicals in urine might kill some pathogens, though, but I wouldn't count on it being sterile. Dec 20, 2014 at 1:25
  • Urine is not sterile.
    – flowerbug
    Apr 27, 2020 at 4:35
  • healthhearty.com/bacteria-in-urine claims that normal urine does not have a significant number of bacteria in it. Discussion & comment on medical.SE is split on it's efficacy for cleaning a wound. Apr 28, 2020 at 12:31

From Mother Earth News:

About a year with straw and comfrey as the carbon materials. This was in a climate cooler than that of Spain.

  • 3
    Read the article again: it was over two years from start to finish.
    – Niall C.
    Dec 2, 2014 at 15:07
  • 1
    It actually says: "After 11 months, the 50 garbage cans were dumped into one large pile. After another year of composting with only comfrey and some old straw, Klehm delivered a fluffy compost"
    – J. Musser
    Dec 2, 2014 at 15:08
  • Read the previous sentence @J.Musser, the one that starts with "For three months..."
    – Niall C.
    Dec 2, 2014 at 15:10
  • 3
    Ah, there it is. I personally think the whole process described is rather unsanitary.
    – J. Musser
    Dec 2, 2014 at 15:12

The best description of the process and issues I have found so far is covered in The Humanure Handbook which is well worth the read.

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