GeneralSoil Biology

Biological Fertiliser – Human Urine

Human urine provides an excellent source of nitrogen, phosphorous, potassium and trace elements for plants, and can be delivered in a form that’s perfect for assimilation. With a constant, year-round and free supply of this resource available, more and more farmers and gardeners are making use of it.

What’s in it?

Urine is 95% water. The other 5% consists of urea (around 2.5%), and a mixture of minerals, salts, hormones and enzymes. It is a blood byproduct, but despite containing some bodily waste, it is non-toxic.


The average urine from a healthy adult will release 11g nitrogen/urea, 1g phosphorus/super-phosphate and 2.5g potassium. The normal range for a 24-hour urine output is 800 to 2000 milliliters (ml) per day with a normal fluid intake of about 2 liters per day. That’s an average of 1400 ml per person, per day!

Fresh human urine is sterile and so free from bacteria. Only when it is older than 24 hours, the urea turns into ammonia, which is what causes the distinctive smell. Antibiotics, vitamin supplements, and other medications will end up in your urine, but in such minute quantities as to be negligible, especially when diluted with water.

How to use it

Urine can be used in a number of ways, such as a solution that is applied to plants to provide a quick, short-term boost in growth or as a nitrogen additive to the carbon-based material, facilitating the composting process. I prefer to use urine for compost building or biomass production as I find long-term fertility solutions preferable to quick fixes.

Let’s look at the various ways it can be used.

Plant feed solution

It is too strong to be used neat on most plants and should be diluted. Dilute one part fresh urine to 10-15 parts water for application on plants in the growth stage. Dilute one part fresh urine to 30-50 parts water for use on pot plants, which are much more sensitive to fertilisers of any kind.

Even when diluted your plants don’t need daily applications, and it’s best used on plants that need lots of nitrogen, such as corn and squash, tomatoes and cucumbers during their fruit-bearing stage.
You can also use it to remedy nitrogen deficiencies. Signs of nitrogen deficiency include yellow or pale green leaves.

Nitrogen deficiency in Tomato (photo by
Nitrogen deficiency in Tomato (photo by

There is a danger of applying too much, and the excess nitrogen can lead to bushy, leafy plants that attract aphids and bear little fruit. Signs of excess nitrogen include curled leaves,

Excess diluted urine can be used on lawns and trees.

Compost additive

Urine can be applied directly to the compost pile. As it’s very high in nitrogen, it should be added to plenty of carbon-rich materials, like dry leaves, sawdust, straw, and cardboard. Urine can act as a starter for compost, encouraging the decomposition process. Undiluted urine can also be applied directly to heavily mulched soils serving the same function as above. The mulch should be thick enough to absorb the urine before it can make contact with plant roots

Straw Bale Stacks

You can urinate directly on a bale of straw, and eventually the straw will decompose and can be used as compost or you can plant directly into the decomposing straw bales.

We use straw bale stacks which are, as the name suggests, simply a number of bales stacked up. These provide excellent habitat for overwintering toads and frogs. When the bales have decomposed the area is perfect for planting trees into. It’s weed free, with mulch and compost right where it needs to be. Build a new pile where you plan to plant a tree in the future and see the toads and frogs quickly move in. Aesculapian Snakes are also commonly found in our bale stacks along with a tremendous amount of invertebrates. The bales on the ground surface will decompose within 12 months even without urine.

Common Toad - Bufo bufo and Aesculapian snake - Zamenis longissimus photographed within one of our Straw bale stacks.
Common Toad – Bufo bufo and Aesculapian snake – Zamenis longissimus photographed within one of our Straw bale stacks.

Applied Directly

Some plants such as Symphytum x uplandicum – Comfrey ‘Bocking 14’ can handle neat urine (See the article Comfrey – Believe the Hype). Following cutting the plants, you can provide each plant with approx. 700 ml of undiluted urine.

Comfrey 'Bocking 14' - Symphytum x uplandicum growing in the under story of our forest garden.
Comfrey ‘Bocking 14’ – Symphytum x uplandicum growing in the under story of our forest garden.

This creates an excellent opportunity to cut out the dilution phase and produce good quantities of high quality nutrient dense mulch for your crops. This biomass when continuously applied to the surface of your beds will help create long-term fertility in your gardens by building up the soil humus levels.


This article originally appears on the Balkan Ecology Project website, here.

You can find this and many more fantastic articles on their facebook page, here.

Paul Alfrey

Hi I'm Paul, Originally from the UK I moved over to Bulgaria with my family 12 years ago and set up the Balkan Ecology Project. Prior to that, I worked as a freelance Arborist in the UK for 15 years. Balkan Ecology Project is a family project run by myself, Sophie and our two boys Dylan and Archie, and supported by the amazing volunteers we have hosted here over the years. We aim to develop and promote practices that provide nutritious affordable food while enhancing biodiversity and work to achieve this by: - Researching, designing and implementing systems on the ground - Providing working examples of our designs at our sites open for the public to visit - Providing quality education and training to aspiring growers and landscapers - Providing consultancy and design for landowners and farmers across Europe - Practicing an open source policy, whereby we disseminate our results freely and share all aspects of our work - Growing, selling and promoting the use of plants and plant communities that have high ecological and nutritional value Our activities currently include: Biological Plant Nursery, Educational Courses, Local Land Stewardship, Polyculture Research, Market Gardening​, and Consultancy and Design.


  1. I am interested in learning your techniques in bio farming and human urine utilization for direct plant growth in public places where the population urinates.

    1. Dear Sophie just think about this: if water is evaporated, residual solid will contain a high percentage

  2. Hi,its great the entire world is opting the path of sustainability,unearthing massive potential in sustainable farming,.we currently run an initiative in Kenya,on soilification as a conservation farming concept with human manure and urine……….the perspective of the whole project is to help us trace back our african roots and traditional farming techniques for sustainability,,,looking forward to partnerships

  3. Ha, I knew it!

    My Korean wife is always saying “if you need the toilet wait until you get home” ie: use it in your own garden.

    Looks like I’ll be weeing into a truckers friend from now on!


  4. Paul, it is very descriptive article. In our area people are using cow urine with cow dung to fertilize the soil. They achieve constant growth and high yield. It good source of nitrogen as described. Highly recommended.

    1. Too much of a good thing !
      Urine has to be diluted min.1:10 sometimes it’s preferable to do 1:30
      (1 part urine 30 part water)

  5. Thanks for the important work you do. Collecting scientific data like this and helping to educate the rest of us!

    Much appreciated!

  6. Hi
    I’m a small grower and use 200lt rainwater tanks to which I add liquid fertilizer to water/feed plants and seedlings. Would it be ok to add urine to the tanks, or does it age even when diluted?

  7. should we stop urine solution to water the fruit plant before pick/havest the plant? for example, should we switch back to water for at least 15 days before picking the fruit? what do you think/suggest?

  8. Sir, I am a retired engineer, presently working as consultant. But i want do something innovative. So i want to set such a project at my own in India. could you please assist me.

  9. Urine is not sterile.
    While it used to be believed that urine contained no microorganisms, based mostly on poor research methodologies and persistent myth, modern research confirms that this is not the case, and that urine from even healthy individuals is teaming with microbiota.
    This is not to say it is bad, as these microorganisms are generally not pathogenic.

  10. I will never pee in the toilete again unles that is the only option… My pee contains 4kg of pure NPK+trace elements(and a bit of mind altering drug metabolites… Ups, pardon me🙄) on an anual level…. I have been peeing under orchard trees for years in spreeng/somer time, but now I will start colecting my pee in 500l water container in my garden in winter time aswell… I am even considering to start colecting my shit… Perhaps a toilet seat with container that I can “flush” with a sawdust… Our excrements are a glodmine of nutrients and we have been flushing it wastfuly with enormus amounts of water… How civilized🤔. Human beeing afraid of his/her own shit?🤔 Perhaps a topic for psihoanalists… 🤔 Obviosley not fezable if you live in a big city for warious reasons, but if you have you litle peace of land tu cultivate it is worth considering… An potential bacteria that migt come back tu you in this proces, are your own, so you cant realy get infectet with some patogen unknown to your own imune sistem and your own simbiotic bacteria in your gut… Panta rey… It almost feels kind a religious to me… My own body being recycled and sustained trugh plants surounding me🤪🤯🥳.
    Perhaps the phrase “eating your own shit” can get a new positive conotation.🤪

  11. My father told me that during the war any form of fertiliser was impossible to get hold of (it was used to make things go bang), and that they would have a bucket with newspaper in it, in the thunder box at the bottom of the garden for you to pee in. As the newspaper decomposed, and the water content evaporated away, it made a good fertiliser and soil conditioner for the ‘Dig for Victory’ campaign.

  12. Urine can also be fermented with sauerkraut juice. This will prevent loss of urea as ammonia, reduce odor and improve it fertilizing properties. You can Google “lactic acid fermentation of urine”

  13. Loved the article but extremely hard to read with the words constantly jumping around due to the ever changing ads. I know it’s not you but this directly affects your readers and or sends them away from your site frustrated. That was actually painful trying to read this information.

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