Better Tomatoes Via a Fertilizer of...Human Urine?
By Rebecca BoylePosted 09.04.2009 at 7:53 am15 Comments
Tomatoes C.P.Storm (CC licensed)
You say tomayto, I say tomahto.
You say Miracle-Gro, I say ... pee.
Apparently, human urine works remarkably well as a fertilizer for tomatoes, according to a new study out of Finland.
Plants fertilized with a mixture of stored human urine and wood ash produced 4.2 times more fruit than plants without the pee, the study found. The urine-fertilized tomatoes had more beta-carotene than unfertilized ones, and much more protein than traditionally fertilized plants.
And the tomatoes were just as good as those grown with traditional fertilizer, according to a panel of 20 brave tasters.
Healthy human urine is rich in nutrients like nitrogen, potassium and phosphate, all key ingredients for healthy plants. As long as the pee doesn't contain any fecal matter, it's usually free of any microorganisms.
Surendra K. Pradhan, K. Holopainen and Helvi Heinonen-Tanski of the University of Kuopio in Finland collected human urine during the winter of 2007-2008 from several eco-toilets in private homes. The urine was stored for about six months at 45 degrees F and tested for microbes and bacteria. The team mixed it with wood ash collected from a household furnace, and found the mixture was just as good as -- or better than -- conventional chemical fertilizer.
In taste tests, the urine-fertilized tomatoes tasted different from those fertilized with urine and ash, but tasters didn't have a preference -- "all tomato samples were evaluated as being equally good by the tasters," the study says. The results are reported in the latest Journal of Agricultural and Food Chemistry.
The same team had previously tested human pee as a fertilizer for cucumber and cabbage, and a South African team reported last year that urine had successfully fertilized maize. The Finnish team said they tried tomatoes because they're grown all over the world and are a staple ingredient in many recipes.
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The Environment, Rebecca Boyle, agriculture, farming, fertilizer, food, Future of Food, gardening, tomatoes, urineThe use of urine to fertilize crops has been practiced since ancient times, but is relatively rare today, thanks to the ick factor and the prevalence of chemical and mineral fertilizers. But as farmers and home growers seek organic ways to grow food, urine could be a solution.
The study "may contribute to the development of positive attitudes about the use of urine and ash as fertilizer as a way to both increase crop yield and reduce water pollution," the authors wrote.
It may not be necessary to go all NASA with our pee and start drinking it. But if we can safely and efficiently grow food with it, why not?
Studies Conclude: Urine in the Garden is a Good Green Thing
Recognizing the value of a free, and abundant, fertilizer for your garden.
By Colleen Vanderlinden
Fri Aug 7, 2009 08:42
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Gardening | Organic Gardening Tips
I read a post by Josh here on Planet Green about using urine in the garden. One of the commenters stated that using urine was completely unsanitary, which is a common statement when the subject of human waste comes up. Earlier in the day, I read an article from Mother Jones about the value of using urine as an organic fertilizer. It appears that we Americans are way behind in recognizing the agricultural value of urine. From the Mother Jones article:
"For more than a decade, 130 households in Stockholm, Sweden, have collected their urine--nearly 40,000 gallons of it per year--and trucked it off to be sprayed on crops. More than 600,000 Chinese households in at least 17 provinces use special urine-diverting toilets to fertilize crops such as sugarcane, watermelons, and peanuts. Farming communities in 17 African countries have also taken up the practice of collecting urine. And in the central Mexican village of Tepoztlán, an environmental group wheels a urine-collecting porta-potty to fiestas and uses the cache on local fields."
Human urine is a very high-quality fertilizer. It is so high-quality, in fact, that a single person's urine would be enough to fertilize up to one tenth of an acre of vegetables for an entire year. There is a certain grossness factor that would undoubtedly turn some people off of the whole idea of using urine on their veggie garden, but before we blow this off as just one more outlandish idea, let's look at what's really going on here.
Set aside the issue of bodily fluids and letting them loose in the garden for a moment. Let's look at what good fertilizers consist of. On any bag of either synthetic or organic fertilizer you would buy, there are three numbers commonly known as the NPK ratio.
N stands for nitrogen, which is important for stem and leaf development.
P stanks for phosphorous, which aids root development, as well as flower and fruit production.
K stands for potassium, which provides for general overall plant health and disease-resistance.
While I have yet to see an NPK ratio for human urine, we do know that it is high in nitrogen, and also provides good doses of phosphorous and potassium. In fact, in a 2007 Washington Post story, they followed a study in which human urine was used to fertilize cabbage (cabbage was chosen because it requires a lot of nitrogen for strong growth). The study found that the cabbages fertilized with human urine were larger at harvest, grew to their maximum size more quickly, and suffered less insect damage than cabbages grown with conventional fertilizers.
One concern that has been raised about using urine as a fertilizer, especially for edible crops, is that any pharmaceuticals that a person is taking could be passed along to the soil and plants via the urine. In the Washington Post story, one of the lead scientists in the cabbage study said that any pathogens that survived in the urine would have to battle it out with microorganisms that already exist in the soil. He also said that, most likely, those pathogens would lose.
Tips for Using Urine as Fertilizer
It's probably best to dilute your urine by mixing it with water. A 50/50 mix would probably be best.
Don't apply urine directly to the plants. Use it to water the soil around the plants instead.
If you take a lot of medications, you might want to steer clear of using your urine as fertilizer. It seems to me that the microorganisms have enough to deal with.
If you'd rather not use urine to fertilize your garden, you can add it to the compost pile.
I know this idea isn't for everyone, but it's an interesting concept, and both the Mother Jones and Washington Post articles touted human urine as a possible option for farmers and gardeners who are low on cash. What do you think? Have you used urine in your garden?
Like this article? Tons more in our Organic Gardening feature.
Robert Ray wrote:
For those of you interested in humanure, composting toilets, urine diversion.
paul wheaton wrote:
"A team of Finnish researchers found that sprinkling tomatoes with human urine mixed with wood ash was the ultimate eco-friendly fertiliser."
Will urine stored in a sealed plastic whitish/translucent milk jug become sterilized after 6 months if the temperature reaches 37 degrees Centigrade, or 100F? The temperature will remain between 30-38C for the majority of the storage during the summer months here. Does it need to be kept from direct sunlight during that time? What about indirect sunlight?
Dustin Smith wrote:Yes, urine is sterile when it first exits the body, however microbes enter the urine and thus we get the smell and urine is no longer sterile. Plus, pathogens can be taken up by the plants you fertilize. It's my understanding that if you use urine directly, (uncomposted/unfermented) then you need to wait about 1 month before harvesting any crop for raw consumption. The exception seems to be that if only your household will consume the products, then they have been exposed to those pathogens before and will not suffer any ill effects. Non-the-less. I'd prefer to kill all the bad stuff and not eat raw crops fertilized with urine. It's safest to cook the crops. Unfortunately, my question remains.
Can you store urine in sealed milk jugs for 6 months over 20 degrees Centigrade and still have proper fermentation to kill viruses and pathogens?