Waste Not: How to Safely Use Urine in Your Home Garden.

 

Using Urine to Feed Plants

Not many people talk about it, but lots of home gardeners do use their pee in their gardens. This practice is centuries old. Some gardeners will use it around fruit trees, or in their flower gardens. Some add it to their compost piles, or to strategically placed straw bales that later get added to compost piles or used to mulch vegetable beds.

Worried about the smell? Read below about dilution. Any smell will dissipate within minutes of application.

What’s safe? Barbara Pleasant wrote about this topic in 2022 on the GrowVeg site. GrowVeg.com is run by the software company Growing Interactive providing the well-known Garden Planner app and lots of online guides and videos.

Barbara Pleasant reports that urine contains important nutrients for plant growth, including phosphorous, potassium and nitrogen, and when handled properly, it makes good plant food. As well as being locally available (!), it’s free, and if you made it yourself, you know exactly what went into it. Plus, if you have flush toilets, you will be reducing the waste of perfectly good potable water.

An adult produces about 3.6 pints (1.7 liters) of urine a day, but don’t expect to harvest it all unless you have set up a convenient system to do so. One adult “pee-cycler” can produce enough for a 1/10th acre food garden.

The Rich Earth Institute

It is important to note that undiluted pee has too many salts to be good for plants. Crops will get burned or stunted. General advice used to be to dilute urine with water at a ratio of more than 10 parts water to 1 part urine, but the gardeners at the Rich Earth Institute have found that nitrogen-hungry crops like sweet corn respond well to a stronger 3:1 mixture. A 5:1 dilution is good for broccoli, peppers, tomatoes and other vegetables that benefit from side-dressing (fertilizing crops during their growth, adding nutrients to boost growth), as well as container-grown flowers. The diluted mixture is poured directly onto the root zones of the plants and watered in to distribute the nutrients into the soil.

The non-profit Rich Earth Institute has turned the area around Battleboro, VT into a pee-cycling hub. They collect over 12,000 gallons of urine annually, from local urine donors, installations in homes and businesses, and their portable toilet service.

Rich Earth Institute recycles human urine into fertilizer, supporting sustainable agriculture and protecting water resources. Local farmers use urine to grow everything from flowers to giant ears of corn using pee collected locally and stabilized at Rich Earth facilities.

The Rich Earth Institute engages in research, education and technological innovation to advance the use of human waste as a resource. After over a decade of recycling urine in Southern Vermont, the Rich Earth team is now helping other communities start programs of their own. They have a Guide to Starting a Community-Scale Urine Diversion Program.

Rich Earth has a video Turning Urine into Gold, from the National Sciences Foundation

https://youtu.be/Hms2rE8B5as

How Urine is Collected in a Community-Scale Program

Here is a diagram of how urine is collected, transported, treated, and applied under their community-scale urine recycling program.

Urine Collection Tools

And here is a photo of the equipment they recommend. The funnel assembly screws securely onto the jug. A ping-pong ball sits inside the funnel, sealing the opening and blocking odors but enabling urine to pass through.

PStyle Personal Urination Device

PStyles are easy-to-use polypropylene Personal Urination Devices (PUDs). They are available in 5 skin-tones, seven other colors and a deep green recycled ocean plastic. Shipping is free on US orders of two or more PStyles direct from the PStyle website. There you can see videos, including one of a PStyle used with the Rich Earth collection container.

The Rich Earth website has two donation buttons, (one for money, one for urine), and a trove of facts:

• Amount of chemical fertilizer that could be replaced with the urine Americans produce each year. 9 billion pounds
• Amount of wheat that could be grown in a year with the fertilizer from one adult’s urine: 320 pounds
• Approximate volume of urine an adult produces each year: 125 gallons
• Water bodies in the US degraded due to nitrogen and phosphorous pollution: Over 15,000
• Portion of the nitrogen and phosphorous pollution in wastewater caused by human waste: 80%
• Amount of drinkable water we use each year to flush toilets:2 trillion gallons
• Amount of water you could save per year by diverting urine for fertilizer: 4000 gallons
• Increase in phosphorus fertilizer price between 1993 and 2013: 270%

Barbara Pleasant wrote about homemade liquid fertilizers including using urine in the garden in Mother Earth News (updated 2024). Readers had some questions about the safety of using urine. The biggest concern has been antibiotic-resistant bacteria lurking in human bodies getting introduced into soil, and thus into the food chain.

Research in 2020 from the University of Michigan (technical and not freely accessible) found that aging the urine makes it lethal to the worst bacteria, such as ampicillin- and tetracycline-resistant bacteria. When urine is set to age in plastic jugs for six months or more, it becomes increasingly inhospitable to a wide range of microbes. Six months at cool room temperature is the current aging recommendation from the World Health Organization.

In France, research is happening using urine to grow grains and other crops. A century ago, Paris recycled half of its urine. Progress is being made developing urine-based packaged fertilizer products in France and Sweden.

French researchers noted that urine contains only one fifth of the nitrogen found in standard fertilizers and less than five percent of the potassium and phosphorus. They tried concentrating the urine and then extracting the nitrogen, but the end product was more expensive than farmers would usually pay. So they tried fermenting it and adding natural bacteria and this worked. One of the researchers went on to co-found TOOPI Organics, a French biotech company that collects and transforms human urine into fertilizer products.

Organic Rules: NOP Rule: 205.105

I am not an Organic inspector or advisor. I just copied and pasted this from the Rules.

“Animal By-products and Materials Allowed

Class: CF Nonsynthetic Parts of an animal and animal by-products that have specific uses in soil fertility are allowed. Includes meat, bone meal, and animal urine that have been treated or handled in a way that reduces contamination by specified risk materials and food-borne pathogens and meets standards for indicator pathogens. See listings under individual generic materials.”