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?


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.

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  • 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. – Brōtsyorfuzthrāx Dec 20 '14 at 1:25
  • Urine is not sterile. – flowerbug Apr 27 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. – Sherwood Botsford Apr 28 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.

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    Read the article again: it was over two years from start to finish. – Niall C. Dec 2 '14 at 15:07
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    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 '14 at 15:08
  • Read the previous sentence @J.Musser, the one that starts with "For three months..." – Niall C. Dec 2 '14 at 15:10
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    Ah, there it is. I personally think the whole process described is rather unsanitary. – J. Musser Dec 2 '14 at 15:12

Composting human excreta has been done for thousands of Years, RF King wrote about it in his journal of Chinese agriculture 'Farmers for Forty Centuries" Depending on size, anywhere from 3 months to 2 years. As long as it reaches temperatures of over 160 degrees Fahrenheit, which is high enough to kill any harmful pathogens that are present in the humanure. Letting the compost sit for a year is extra insurance against pathogens, as they cannot survive for an indefinite period without a human host. the East managed to feed a large population without polluting their drinking water. Meanwhile, cities in medieval Europe turned into open sewers. brought recurrent deadly epidemics of cholera and typhoid fever throughout the western world. China maintained an agricultural system that was based on human "waste" as a fertilizer. Stools and urine were collected, sealed and transported considerable distance and composted with no pollution of drinking water, and an agricultural system that could have lasted forever. In fact, it did last 4,000 years.

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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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