Actually, I should say “Use the fertilizer you’re already making.” While I believe compost is the best way to improve soil in most respects, growing food does remove nutrients from the soil. Compost can return some of these nutrients, and add nutrients if compost is “imported” as I do by bringing in leaves and manure from outside my yard. But, why not add a little fertilizer to help replace those nutrients? The good news is that you already have this fertilizer available and it’s free. You’re simply flushing it away, day after day. An Op-Ed piece in today’s New York Times talks about the need to change how we handle human waste (feces and urine) for environmental reasons. The article focuses on large scale waste issues. Here, I want to talk about small-scale human waste issues and how you can use them to your advantage.

Human waste has been used for millenia to fertilize crops. Unfortunately, our systems and laws are set up for centralized processing of human waste, instead of allowing for local use of these resources. This means that your local codes don’t make it easy to build a composting toilet or to use a urine-diverting toilet. As pointed out in the Times piece, the first step in correcting large-scale waste problems is diverting urine from solid waste.

At home, on a small scale, saving solid waste is more difficult, because it must be stored and “aged” for about a year to kill off any potential pathogens. Urine, however, can be diverted by simply peeing in a bucket or other container. Because it is naturally sterile and high in nutrients your plants will love, you can use it immediately without storage.

So, to “come clean” about my practices, I have been using urine for about a year. I simply save my urine from night-time visits to the bathroom when I want it for fertilizer. I used this on my vegetable garden last summer and more recently, before the weeks of rain we’ve been having, I added a half-gallon of urine to five-gallon buckets of water used to irrigate my fruit trees (a.k.a. my drip irrigation system).

If you want to know more, I recommend these two resources:

  1. Liquid Gold: The Lore and Logic of Using Urine to Grow Plants by Carol Steinfeld. While not the best written book, it does provide a primer on collecting and using urine at home.
  2. Urine diversion: Hygienic risks and microbial guidelines for reuse by Caroline Schonning. This is a more technical paper from Sweden. As usual in the environmental area, Europe is far ahead of the U.S. on these issues. This paper provides a good example of Sweden’s work in this area.