Human Urine as Fertilizer

For thousands of years, people have used human urine as fertilizer. But in our sanitized world of indoor plumbing, the thought of fertilizing with human urine is less than appealing. However, if you need a free source of nitrogen, perhaps it might be worth considering, especially if you enrich the mix with needed trace minerals.

Urine is a good fertilizer

And why not? Urine makes a great fertilizer. One liter contains approximately 10 grams of nitrogen, 2 grams of potassium, and 1 gram of phosphorus, plus other minerals needed by the plant. The amount of nutrients in urine fluctuate according to a person’s diet and the concentration of the urine.

Applying 1 gram of nitrogen per square foot equates to 100 pounds of nitrogen per acre, which for many crops is more than enough for a whole year. (To see the formula for calculating the number of pounds of NPK in liquid fertilizer, click here.)

What area will one person's urine fertilize?

One day’s worth of urine (about 1.3 liters) contains around 14 grams of nitrogen. Therefore, as a ball park figure, a day’s worth of urine is a year’s worth of nitrogen for a 3’ x 4’ area. Multiply this by the number of days in a year, and you will find that one person’s urine meets the annual nitrogen requirements for a 50’ x 110’ area. To see a study done with human urine as compared to commercial fertilizer, click here.

It has been calculated that one adult’s urine has 50% to 100% of the minerals needed to grow food for one adult. Why waste this valuable resource? Rather, as recommended by Dr. Mercola, recycle urine as fertilizer. This can be especially helpful in urban communities where other fertility options, such as items to compost, are limited. Recycling urine also saves the 15 to 20 gallons of water a day needed to flush away urine.

Collecting human urine

I found an old gallon sized salad dressing bottle with a very wide lid that worked great for collecting my urine. Each day I empty it into a 2 gallon watering can, fill it with water, and then use it where needed. Another idea is to use a 2 gallon kitty litter container. Just use it for a 24 hour period, then fill the container with water and apply.

To sanitize the empty container, dump in 2 tablespoons vinegar and 1 teaspoon hydrogen peroxide to prevent bacteria growth, and just start using the container again. Both vinegar and hydrogen peroxide are beneficial to plants.

Please take a minute to visit my home page, Healthy Vegetable Gardening. Happy gardening!

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