Using Urine as a Fertilizer in Your Home Garden

Believe it or not, human urine contains almost the same ingredients in the same proportions as a bag of fertilizer. So why aren’t we all just peeing on our lawns and gardens?

In one year, the average human being produces enough urine to fertilize 6,300 tomato plants which would produce 2.41 tons of tomato fruits in just one season.

ABC News Technology & Science column, Sept 9, 2009

Using urine in your garden is more efficient than bagged fertilizer.

Undiluted urine is extremely high in nitrogen and sometimes high in salts. Because of this, the high nitrogen content can actually “burn” the plant it comes in contact with. This is why your grass turns brown where your dog pees.

Dilute urine with water, however, and it’s more efficient than any chemical fertilizer. Urine from a healthy human is rich in nitrogen, potassium, and phosphate, which are all essential for healthy plants. If you look at the ingredients on a bag of chemical fertilizer, you’ll see the word “urea”, which is present in, you guessed it, urine.

Also from the ABC article quoted above:

“Surendra K. Pradhan, K. Holopainen and Helvi Heinonen-Tanski of the University of Kuopio in Finland have found that wood ash and human urine perform just as well as more expensive mineral fertilizers while doing less damage to the environment. The combination is rich in nutrients, nitrogen, phosphorus, potassium, calcium, and magnesium.

“The researchers raised a healthy crop of tomatoes in a carefully controlled series of laboratory experiments. The plants were grown in four different ways in a greenhouse. Some received no fertilizer, some received commercial fertilizer, some received just urine, and others received human urine and birch ash collected from the furnace in the home of one of the participants.

“During the growing period the plants that received commercial fertilizer and those that got the urine and ash performed about the same, substantially higher than the ones that got only urine, and four times greater than the unfertilized plants.

“Urine was collected from several eco-toilets in private homes, the study says, and stored for about six months (at 45 degrees F) while the researchers analyzed its “microbiological properties.” No harmful substances were found.”

Okay, but you may feel that peeing on your plants is “yucky”. Maybe it is, but let’s look at the bigger picture: this may contribute to successful agriculture in the developing world, where chemical fertilizers are failing miserably and decimating already damaged, eroded soil. They may also at times be in short supply for economic reasons or civil unrest.

Urine is used as an agricultural fertilizer in developing countries

“In Uganda, members of Nezikokolima Farmers Group in Nabuti Village, Mukono District have substituted the use of compost manure with human urine to fertilize their gardens and they say their vegetable yields are impressive.

“It was introduced to the group by the Ecological Sanitation Project commonly known as EcoSan, implemented by Kampala City Council.

“Human urine contains a bulk of nutrients and it is a quick acting fertilizer which…can boost farm productivity,” says Dr. Onesmus Ssemalulu, a soil scientist with Kawanda Agriculture Research Organisation.

“Patrick Makhosi, also a soil scientist with Kawanda Agricultural Research Organisation says that applying urine once every week for at least two months will more than double the yield of vegetables. The urine should be diluted with water at a ratio of 1:9 and applied to the plant where the stem touches the ground.

“Whenever we brought the urine, we would keep it in tightly closed containers for at least 14 days to facilitate decomposition and the death of disease causing pathogens, making it safe to both the users and the plants,” says Jessica Kalema a member of Nezikokolima Farmers Group.”

All Africa Global Media

Is urine okay to use on plants?

According to the Washington Post, it sure is. In fact, they say that farmers need look no further than pee for nitrogen and other minerals:

“Urine is “a good natural nitrogen-containing substance and probably could be easily utilized” as a fertilizer, said Dr. Philip Tierno, director of clinical microbiology and immunology at New York University Medical Center, New York City. “There’s nothing wrong with using it,” Tierno said. He added that there is little risk of contamination by urine-borne pathogens because they would be in competition with microorganisms found in the soil and would “probably lose the battle. Urine is actually a relatively clean substance.”

“Human Urine Safe, Productive Fertilizer”, The Washington Post

So while the “ick” factor may still exist in your mind, I just wanted to show the science behind using your own urine as fertilizer. After all, it’s a waste product just like any other mammal’s and we use plenty of their waste in organic fertilizers.

If you’re healthy and you want to make the leap, it should be perfectly fine to use your own diluted urine as a garden fertilizer (10 parts water to 1 part urine is the suggested dilution). Folk wisdom also claims that it’s an excellent way to keep critters like rabbits, deer, and squirrels out of your garden. It’s also a quick nitrogen boost for a struggling compost pile.

Just thought I’d put the science out there for your consideration.