Betsy started using our own urine to fertilize our backyard garden last year, saving it in buckets in the bathroom and then diluting it with 10 parts water. This week I tried it on my community garden plot because I was concerned that the heavy rain had caused nitrogen to leach out of its sandy soil.
I had the same “yuck” feeling many of you may have, but after doing some research I learned that Asian peoples have been using urine as fertilizer on vegetable gardens for thousands of years. I liked the idea of a free fertilizer, and the conservation of water from not flushing the toilet as much.
Human pee is sterile when it comes out of the body, I learned, and is not a health risk as long as the provider is healthy. It contains not only nitrogen but phosphorous and potassium, which every plant needs, as well as trace elements. Some people recommend using it within 24 hours of its creation, but we weren’t that meticulous. After dilution, it doesn’t smell bad, though Betsy, who has a keen sense of smell, disputes this.
For seedlings or potted plants, people recommend diluting pee to 30-1 or 50-1. Fertilizing the garden with diluted pee every two weeks is about right, I read. Pee can also be used, undiluted, as a way to speed up the decomposition in a compost pile.
I read about organized pee-collection drives. In Stockholm, 130 households collected 40,000 gallons in a year and trucked it out to gardens outside the city. Closer to home, the Rich Earth Institute of Brattleboro in May was seeking to collect 6,000 gallons of donated urine for studies funded by the federal government. The institute provided male donors with a waterless urinal and women with a toilet insert, and signed up volunteers at the Brattleboro Farmers Market and a fair on June 7. The goal is to figure out the best way to fertilize hay with urine, and to see if pharmaceutical chemicals can get into plant tissues, soils and groundwater.
For me, the biggest concern is over-fertilizing, especially my tomato plants. If tomatoes get too much nitrogen, they grow lots of beautiful green foliage but don’t produce many tomatoes. I used four gallons of a 10-1 water-pee mixture on about 350 square feet of garden. We’ll see how it works!