In Jan 2014 I wrote a fairly extensive blog post, with references, about use of urine as a fertilizer. I won't repeat that discussion, but
link here. I still think it's an important concept, and worth repeating. These are the learnings for 2015, almost 2 years later.
-Peecycling means saving urine in a container, for use in the garden.
-Urine has similar organic plant nutritional value, as organic fish emulsion.
-The main ingredient in urine that contributes to plant nutrition, is urea nitrogen.
-If
stored, the urea nitrogen is broken down into ammonia and carbon dioxide. That results in a
highly alkaline solution that sterilizes any potential pathogens. If used directly, th
e soil bacteria do the same thing. Used as described here, I don't think the alkalinity is enough to change the pH of the soil in any meaningful fashion. Soil here is acidic, so if there was an effect, it would be beneficial.
-Urine is
safe. Urine from a healthy person does not cause a risk for infections. To sterilize the urine, it can be stored for a few weeks.
-The main negative is
salt content. Don't add more salts to an already salty soil. My Pacific NW soil is very low in salts, based on recent laboratory soil testing. So that is not an issue here.
-In my soil, there is plenty of
potassium and phosphorus, and most trace nutrients. Nitrogen is the main soil nutrient that is needed. Urine is very low in potassium and phosphorus, so likely doesn't change those nutrients much, unless the soil is deficient. Then the contribution would be helpful.
-In other soils, there are different needs. There is a movement against adding phosphorus, which harms the environment. Potassium is often high - a
soil test would be needed to determine that.
In 2015, I used peecycling for nitrogen-demanding garden plants, especially
corn,
tomatoes, and
squash. I did not do a randomized trial, comparing plots with and without. So this is not a valid university trial.
We saved the urine in plastic bottles from orange juice or cider. Most were approx 2 quart size. For fertilizing, we poured it into a 2-gallon watering can, then rinsed the pee bottle 3 times with water, pouring the water each time into the watering can. So that is a 1:4 dilution. We poured that on the ground in the corn row, or around the tomato or squash plants, about one watering can full per 100 square feet. We estimated the 100 square feet as about 5 X 10 feet, guessing the distances.
If stored, some
dissolved minerals bind to the sides of the container. I'm thinking those are
potassium phosphate, or ammonium salts, but not sure. This can be unsightly on the bottle, but is not harmful. After emptying the bottles, they can be filled with water and left sitting for a week. The water dissolves those minerals, resulting in a cleaner looking container. Sometime 2 water treatments are needed. I use that water for watering as well, those minerals also go into the soil, so nothing is lost.
In all cases, after watering the diluted into the soil, I watered again with a second watering can with just water. That soaks the diluted urine a little deeper. I did not notice any odor, although I may not be sensitive enough to know.
The result was
excellent production of all three. I was very surprised at how well they did.
Corn, squash, and tomatoes, all had excellent yield. The plants grew vigorously and fast, and the production was excellent - large fruits and excellent flavor. We had the most tomatoes and squash that we have ever had. This was my first time for sweet corn, which was excellent. All three crops received the fertilizer at 2 or 3 week intervals, until the corn tassels start to grow, or the tomatoes start to bloom, or the squash starts to bloom.
For some flowers and herbs, I also used the same fertilizer. I quit when the flowers started to grow.
Chinese chives were big and tender, and rebounded quickly from harvest for second and third and 4th crops.
Nasturtiums grew too large, making big bushes with very large leaves and few flowers.
Daylilies were big and vigorous, and made many beautiful, big, flowers.
I used much smaller amounts for the
young shade trees, using one diluted bottle per tree, in late winter and repeating in early spring. Those were watered in extending to the drip line and a little beyond. Growth was excellent.
Linden trees, maples, and
ginkgos responded very well to the additional nitrogen In fact, I was kind of awed at how much growth the maples produced -
more than 3 foot of sturdy, stout branch growth.
I did not use nitrogen boost for the producing fruit trees that are already big enough - the plums and the cherries. If they were smaller, I would have. I do not want to overstimulate leaf and stem growth at the expense of fruit--bearing growth. For
persimmons, I read that extra nitrogen can lead to fruit drop. Those trees were so small and young, I did fertilize them to stimulate more growth. I read that the first year fruit often drops, and they did. This year the Asian and Asian/American hybrid are tall enough, and will get no extra nitrogen in 2016. The American persimmons are still very small, so I will fertilize those in early 2016. The
pawpaws grew very well, and have many flower buds now. I don't think that fertilizing them prevented formation of next year's fruiting wood, and it did stimulate growth a lot. I will fertilize the smaller ones and not the larger ones.
Apples and
pears are susceptible to
fireblight. Rank, excessively vigorous growth is especially vulnerable to the disease, especially in the early Spring. I have seen that happen, fast rank growth suddenly looks like it has been torched. So for the smaller pome trees, it's a gamble. You want them to grow well the first couple of years, so you don't have to wait too long for the onset of production, especially the first taste. The
pear trees and
Asian pears are all big enough, so they will get
no nitrogen boost. Some of the
apples are big enough - they won't get any, or won't get much. The smallest apples might benefit from the extra nitrogen during their first year.
I thought about this when I bought the Maxie pear this week at Tsugawa nursery. In the ground, this tree is 8 foot tall. It is plenty tall, so needs no nitrogen boost. If I bought a whip by mail order, shipping requirements result in it being much smaller and shorter, and I think I would have to wait longer for it to bear, or risk fireblight by fertilizing.
Figs are more sensitive to freezing if the growth is too rank and soft. For the smaller ones, which is most of the Battleground fig trees, the plan is fertilize early - say, May, but not after that. Use about 1/2 as much as on the corn, so 1 original 2 quart bottle goes to about 200 square feet. That method worked nicely this year, and all growth was hardened off well before the first frost. Most of my Battleground figs are in the 3 or 4 foot tall range, so still some growth is needed before I get significant production. I hope to get a few bowls of figs here this year, and still have the big, very productive, Vancouver figs to satisfy me for the next year.
If you
fertilize and the growth is fast and tender, then there is
no rain, you risk
losing the crops to leaf burn. Ditto for concerns about salts. Concentrated salts lead to leaf burn and in severe cases, can kill plants. Think of lawn spots where dogs urinate. This can be a motivation to reduce salt in the diet, healthier for all.
By diluting and watering the dilute urine into the soil. we did not have any leaf burn issues at all, on any of the plants that we fertilized. This was an especially hot, dry, summer. We watered the vegetables and youngest fruit trees regularly, but only watered the young maples, lindens, and maples, 2 or three times. Those are in the range of 10 to 20 feet tall. They did not have any leaf burn at all.
Since we are planning some beds for chicken feed next year - seed sunflowers, milo / sorghum, and flint corn - I want to save some urine for spring use. The same large juice jugs should work fine. Many writers recommend
storage for auto-sterilization. There is more odor, which passes fairly quickly, especially when watered in. There are no special requirements. The jugs can be stored in shed or garage. Some of the ammonium content is lost due to the alkaline state of the stored product. Used quickly on opening, and watered into the acidic soil, I think this loss would not be a lot. At least for manures, ammonia loss are significant only
if the manure is left on the soil surface. Loss is also less if applied to tilled soil instead of residue, and in cool temperatures. Similar concepts apply to
use of diluted urine.
No fertilizing regimen is a cure all. Judgement about which plants to fertilize, when, and how much, is important. Every plant has it's own needs, and those needs change with stage of growth. This method is mainly good for nitrogen-demanding plants at the time that they need extra nitrogen. For the past 2 years, this is the only fertilizer that we have used, and the results were all positive.
Some people are very squeamish about peecycling. On a web forum, several members were close to horrified about the topic, some spread misinformation and one member was almost threatening. In addition, it's anatomically much easier for men than for women. No system can be suitable for everyone in every circumstance. A lot of education is needed to improve acceptance and reduce prejudice. Peecycling, is sanitary, prevents excess nutrients from going into rivers and streams, probably prevents medications from going into rivers and streams and disrupting fish reproduction and concentration into fish. Peecycling conserves water, reduces reliance on chemical / natural gas production of nitrogen, so is a responsible measure for those who, like me, want to be stewards of the environment and reduce our own role in climate change. Peecycling is hygienic, safe, responsible, easy, and effective for many crops.
(All images public domain, from
vintageprintable.com)
Addendum. Pee-cycling is now almost sort of mainstream, to the extent that you can purchase P
eecycling Coffee Cups and
mugs. Maybe people are less squeamish than I thought.
