The Aztecs (among many peoples) used urine to clean wounds and prevent infection.
Until the 19th century, clothes were washed using old urine as detergent because of its high ammonia content11.
Some people drink their own urine, especially morning urine, which is more concentrated, as it is considered beneficial by some therapists. This is called urinotherapy or “doing amarolil”, a practice that originated in India.
Urine is a good source of nitrogen and other minerals and, when used correctly, is a completely safe fertilizer. Using urine as fertilizer saves money, fossil fuels (widely used in the production of chemical fertilizers) and water (no need to flush!). It also reduces river pollution - urine is an important source of nitrogen which contributes to the eutrophication of the river if denitrification is not used in the water treatment plant. And that's no hindsight, even space technology uses it - NASA has used urine in hydroponic growing systems!
- Isolate it. The golden rule is to separate urine from other bodily waste. Urine is clean and should be kept as it is. Pee in a bottle, or invest in a urine separator for the toilet.
- Use it when fresh. We all know the smell of urine after several hours. It comes from ammonia, which is made from nitrogen. The more your urine smells, the less nutritious it will be for your plants, and the less pleasant it will be for you to use it.
- Always dilute. Urine is too strong to be used directly on plants. Dilute to at least 5:1, and even up to 10:1 for softer plants and seeds.
- Water the roots. When watering, try not to splash the leaves, but pour urine at the root. This saves on evaporation, and the dry leaves are much more resistant to disease.
- Distribute well. Urine can be salty, and using too much in one place can harm plants. Use it in your garden so you don't risk overdosing, and don't use it on the same plant every time.
- Feed hungry plants. The plants that will benefit the most from urine are those with the highest nitrogen requirements. Try it on leafy vegetables like cabbage and cauliflower, corn, or any other plant that needs a little sprucing up.
- Other uses. Undiluted urine is too strong to use directly on plants, but it can be used as a weed killer. Within a few applications, especially on hot days, your weeds should be gone. It can also be used neat in a winter spray for fruit trees to discourage fungal diseases.
- Activate! The final use of urine in the garden is as a compost activator. The nitrogen content in the urine will speed up the composting process.