Urine in the garden

The subject is a bit taboo, I know! But even Larry talked about it in 2020, after much hesitation, following a question from a reader. In that article, the focus was on using diluted urine as a fertilizer, which is a very good idea, because the N-P-K formula, estimated at 11-1-2, is similar to commercially available nitrogen fertilizers. Larry also mentioned its use pure as a compost gas pedal. That’s great too, especially for carbon-rich compost such as leaf litter. If you sprinkle it with urine, it will balance the C/N ratio and stimulate the process.

Photo: Darkest.

Urine as a Fungicide

I use it every spring as a fungicide on my currant bushes. Urea is a natural fungicide; we produce it several times a day, and it’s free. However, it’s imperative to apply it at the dormant stage, i.e. in March or April (earlier in some areas), as the urine burns the foliage! I’m no plant pathologist, but I understand that urea destroys spores or remnants of diseases that have overwintered on shrubs. Ideally, you should use a sprayer to apply a fine mist to the branches and soil around the shrubs. After budburst, it can still be used in dilution (add four times as much water), but this is less effective. This treatment is useful against powdery mildew and anthracnose. But I’ve heard of apple growers using it successfully on apple trees to reduce scab. At home, if I miss this spring operation on my currant bushes, they lose all their leaves before the end of August.

How to Collect Urine

In the comments on Larry’s article, many people were concerned about how to collect urine, especially women. It’s simple: how do you provide a urine sample for medical purposes? A small plastic jar does the trick for me. I transfer my urine to a plastic bottle, which I keep in the fridge for a day or two before using it in the garden. Sometimes I freeze it for future use, on compost for example. Don’t forget to identify your container, as a family member might mistake it for apple juice!

Unfortunately, there’s a great deal of disdain for human waste, especially in North America. Here in Quebec, our own environment ministry, is still wary of composting toilets, also known as dry toilets.

Composting Toilet

Some twenty years ago, Nature-Action Québec produced plans for a composting toilet for outdoor use: a very simple little hut consisting of a toilet seat placed above an aerated box. Each time you go to the toilet, you add a little sawdust on top: one cup for #1 and two cups for #2. There’s no unpleasant odour. After 6 months, you can transfer the contents to the open air and, after a year and a half, everything will have decomposed perfectly. Of course, since we’ll also be composting faecal matter, it’s best not to use this compost on edible plants. A compsting toilet is a great option for places where there’s no access to water or electricity… but it’s forbidden in Quebec! I had one installed at a rest stop in my little town, but it had to be removed after a few years, as our government prefers the public to relieve themselves directly in the woods.

Exterior of a composting toilet.
Interior of a composting toilet.

Dry Toilets

In France, dry toilets are permitted and even encouraged by ADEME (Agence de l’Environnement et de la Maîtrise de l’Énergie). A leaflet, with all the sanitary details, is available for those interested. Some companies even rent out portable dry toilets for events in Europe. This would be much better than our rather unpleasant-smelling blue portable toilets!

You’re going to tell me that I’m straying a little from the favorite topics of this blog, and yet: it’s a natural product that’s very useful in gardening!

Edith Smeesters is a biologist and a pioneer in ecological horticulture in Quebec. She has given countless conferences and workshops and written several books on the subject for over 20 years. She founded and has been president of several environmental organizations, such as Nature-Action Québec and the Coalition for Alternatives to Pesticides. She was a key figure in the creation of the Pesticide Management Code of Quebec, which has been in effect since 2003. She has received several awards for her involvement in the environment and is a member of the prestigious "Cercle des Phénix".

7 comments on “Urine in the garden

  1. heathergrammie

    Funny how practically everyone accepts animal manure as fertilizer but human urine makes a lot of those same folks squeamish.

  2. Although unrelated, it can dissuade some sorts of vermin. Unfortunately though, it does not seem to dissuade the most bothersome sorts.

  3. Ib Andren

    My father ran a flower nursery near Copenhagen. His speciality was Dahlias. He always had a barrel in which the workers collected urine which was then used to fertilize the Dahlias. I have no idea what dilution was used. This was about 70 years ago.

  4. Ellen Asherman

    I have read that urine applied to roses in early spring (diluted 1-10) will give them a needed boost of nitrogen to get the leaves growing. I’m going to try it – very carefully?

    • Mathieu Hodgson

      Depending where you are, early spring is an appropriate time for such fertilization as plants are entering a growth phase and can use the nitrogen boost. Make sure to do it when your roses are no longer dormant so they can use the nitrogen.

  5. Informative post, and I always appreciate a learning opportunity.

  6. Gertrude van Voorden

    This article is proof people have no idea about the waste, biosludge used commercially on vegetable plants. When the liquifidication of corpses takes flight this will probably increase. Even MRNA is used on salad growing. Then the pesticides that give people living nearby Parkinson and other diseases. Killing dogs locally recently.

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