Monday, May 11, 2015

How and Why I Put Urine To Good Use in My Garden

I've been busy in my gardens whenever I have a hour or two of free time.  The gardens usually take priority over my other hobbies during the day, one of which includes writing articles for the blog.  That is partly the reason for the lack of updates over the past few months, with the other part being that I've had a hard time coming up with topics for posts that haven't already been done by people more experienced and knowledgeable than myself.

All that aside, I want to talk a little about something generally considered a waste product, and how to turn it into a valuable resource. 



Wasted to Worthwhile

Urine is that thing I was referring to.  I have started using my own collected urine as a fertilizer for my edible plants.

Most people would understandably be put-off by this, as the culture of the United States is to consider urine a waste product, something that is "gross" and "unsanitary."  But from a scientific perspective, urine is a wonderful (and relatively safe) resource for growing plants.

First off, urine is unlikely to harbor any harmful pathogens as it is leaving the body.  While it is a stretch to say that urine is completely sterile, the bad bacteria like e. coli and salmonella probably aren't in it unless it was contaminated after leaving the body.  For the truly paranoid among us, research has shown that urine stored for eight days at 86 degrees F will eliminate virtually all bacteria in it.  But if the urine you're using is being collected from yourself or your family, it's most likely harmless.  Sterilization is usually necessary when the urine is also contaminated with feces.  Not an issue in home collection for the garden.

Urine has an NPK ratio of about 11:1:2, which makes it ideal for fertilizing plants like lettuce, where the leaves are harvested as the edible part.  It is also ideal for heavy nitrogen feeders like corn.  This PDF has all the info on various plants that benefit substantially from urine fertilization, as well as others plants that benefit from it, but not quite as much.  Add in some wood ash, however, and you have a super inexpensive, commercial-grade fertilizer.

I have not personally mixed wood ash with my urine to fertilize my plants, but I pour diluted fresh urine around my leafy greens, such as lettuce, spinach, and kale.  I also give small amounts to my tomatoes, beets and green beans, but only once or twice a week.  I don't want the plants that need to produce flowers for fruit to become vegetative monsters from the high nitrogen content.

Beets looking good.

Urine-fertilized lettuce is bountiful this year, and the kale behind it is gaining some size.

My tomatoes have really started growing now that the temps are getting into the 80s.


If I have to pee a lot, any extra urine gets dumped on the compost.  Using urine as a fertilizer/compost additive not only reuses something that generally goes to waste, but also helps conserve water by not having to flush the toilet as often.  It brings us another step closer to being self-reliant in our own back yard.

Now, using urine from healthy individuals as plant fertilizer should be no problem, hygienically speaking.  However, if you or your family members have a UTI or some other type of infection, it might be best to not use your pee on your edible plants until the issue is resolved.  I couldn't find any specific examples of urine spreading infectious disease, but better safe than sorry.  I've also heard concerns about prescription drugs lingering in the soil, supposedly deposited by urine.  There is some concern that the plants might take up trace amount of these drugs during their growth.  As before, I haven't read any specific examples of this occurring, but in this case, I am a bit skeptical of any risks of this being hazardous to health in any way.  Until further research is conducted, though, you may not want to use urine to fertilize plants if you are taking medications... just to be safe.

I also use my urine to fertilize my flowering plants.  They seem to enjoy it.
Despite the relatively low risk of pathogenic agents being in human urine, the World Health Organization still has some basic guidelines on how to minimize risk of infection even further:

  • Refrain from using urine as a fertilizer at least one month before the plant is to be consumed

Given the results and the relative safety of using urine as fertilizer, I will be putting my own supply to good use in my garden.

Hope you enjoyed this quick article on a "home made" fertilizer.  I want to have more frequent updates to the blog as the garden work transitions from "getting everything going" to more of a maintenance mode.

My next article topic will be on the water-saving ground feature, swales, and I plan on showcasing my own designed swales in my small suburban garden.  If we can ever get some decent rainfall here in the mountains of North Carolina, maybe I can make a video of them in use as well!  Until then, keep at those gardens.  I know I will.

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