Use Your Pee to Grow Your Peas

By: Kate Morgan  | 
urine as fertilizer
Spending a ton of money on fertilizers and soil additives? Both flowers and vegetables need all the nutrients that are readily available in your very own urine. Vizanty/Shutterstock

There are basic building blocks that plants of all kinds need in order to grow; among them are water, phosphorus, potassium and nitrogen. The elements are found in soil, and if their concentrations aren't high enough, most gardeners solve that problem by adding fertilizer.

Fertilizer comes in many forms; almost any organic matter can add nitrogen and phosphorus as it breaks down, and garden centers often carry formulas made of cow's and pig's blood, fish emulsion or mollusk and crustacean shells. And perhaps the most common fertilizer is manure. The waste of animals like cows, horses, chickens and rabbits is loaded with nitrogen and phosphorus.


But human waste is, too. At least, our urine is. For thousands of years, humans have understood that urine is great for helping crops grow. It contains all the phosphorus and nitrogen a garden could need, plus healthy amounts of potassium and trace elements. And while urinating is one of the ways our bodies remove waste, it's not toxic to our gardens. In fact, it's nearly sterile and presents no real risks. On the International Space Station, it's even recycled into drinking water.

Urine is a super effective fertilizer, too. Researchers studying farms in Niger found that fields fertilized by the farmers' urine produced 30 percent more grain than fields fertilized with other products. And, though it may seem a little odd, it's totally safe. A 2020 study found that any potentially dangerous microbes that are contained in human urine are reliably eliminated by storage conditions or pasteurization.

So, if you're willing to give urine fertilizing, well, a go, here's how to get started.


Step 1: Collect It

Step one may be a bit obvious: You've got to collect the urine. People approach this in a number of different ways. Some simply reach down with some kind of vessel to collect it. Others use a system like a 5-gallon bucket and a "Luggable Loo" seat. If you plan to save up a decent amount before using it in the garden, it's wise to keep it in a container that has a lid. (Or, get creative, as this gardening blogger did using charcoal!)

The one thing that's very important is to make sure there's no cross-contamination with fecal matter. While urine is sterile and safe, human feces contains bacteria and other pathogens that can be super dangerous and that can spread to vegetables if they make it into the garden. So be careful: pee only!


urine as fertilizer
Michael Roes, founder of Toopi Organics, poses in front of containers filled with human urine, June 3, 2022, in Loupiac-de-la-Réole, France. The company uses 66,000 gallons (250,000 liters) of human urine every year to produce an agricultural "bio-solution" to reduce the use of chemical fertilizers in agriculture.

Step 2: Dilute It

Urine has lots of good stuff in it, but plants can suffer from too much of a good thing. For most vegetables and flowering plants, undiluted urine is too "hot." Excess nitrogen, especially, can burn a plant, weakening it and — in the case of edible plants — causing crops to turn bitter. You can avoid fertilizer burn by simply diluting the urine. The ideal mix is about one part urine to eight parts water.

If this seems like too much work, or the idea of urine collection is too daunting, you can also cut out the first step and simply pee in the garden. Just make sure you have a super thick layer of wood chip or leaf mulch that'll protect the plants from the concentrated stuff. Even still, direct application can be a bit risky for your plants' health.


Step 3: Compost It

If you're collecting more urine than your garden needs, you can compost the excess. The best compost piles are a balance of greens and browns. Nitrogen-rich materials are the greens, while the browns are rich in carbon. Urine counts as a green, so you'll need lots of browns — think cardboard, paper and sawdust — to help balance it out. Even if you're not planning to use a ton of urine, it's kind of a compost secret weapon. If you've got a pile that seems slow to decompose, just pop a squat: Urine can act as a "starter" for the breakdown process.

urine as fertilizer
A farmer pours urine into a container in Lilongwe, Malawi, Oct. 30, 2020. Fertilizer made from human urine is slowly replacing chemical fertilizers among many farmers in some districts of Africa. 
Xinhua/Joseph Mizere/Getty Images


Step 4: Harvest the Spoils

When your vegetables are ripe and ready to harvest, simply enjoy the fruits of your labor. You should know, though, that while some places accept human urine as fertilizer, others have restrictions around it. If you're fertilizing your own garden and you plan to eat the harvest yourself, you're in the clear. But if you sell your vegetables, make sure you're aware of the rules in your location.