Does Urine Kill Plants? – All You Need To Know About This Human Waste

Yes. Undiluted urine is acidic and can kill plants. Urine is an aqueous solution comprising creatinine, urea, dissolved sodium, chloride, and potassium ions, and at least 95% water. It also includes organic and inorganic compounds. An excess amount of urine in the soil can lead to toxic nutrients, which will eventually kill the plants.

But, if diluted, human urine is beneficial to plants due to its high nitrogen and phosphorous content. The human kidneys secrete this solution, and it is an excellent source of valuable nutrients that enhance plants growth, especially leafy vegetables. The ionic nutrients in urine can be compared to those found in chemical fertilizers. 

In this article, we look at why urine would kill plants, its benefits in the garden, and, how to use it. Read On!

Why Would Too Much Urine In The Soil Kill Plants?

Urine contains dissolved sodium ions, among its other components. If excess urine is applied on the agricultural land as fertilizer, it will lead to a lot of sodium getting into the plants. Sodium interferes with the water uptake by a plant’s roots which competes with other nutrients, thus inhibiting growth. 

Human urine also contains nitrogen, which could also lead to the plant’s death when in excess. Too much urine in the soil could cause toxic levels of nutrients, including nitrogen. But, if the levels are kept in control, the nutrients are beneficial to the crops. 

Studies have shown that urine also contains some pathogens, salts, and pharmaceuticals, and the use of large amounts on the soil can inhibit the growth of spinach, cabbage, and carrots. Excess amounts of urine will also increase the electrical conductivity of the earth. 

What Are Some Benefits Of Applying Urine To Your Garden?

Urine has various uses and benefits in the garden, including;

Use As A Fertilizer

Urine, just like commercial fertilizers, contains large amounts of nitrogen which is essential for plants growth. This nutrient helps the plant’s manufacture enzymes, amino acids, chlorophyll, and proteins necessary for all crops. You can use urine as a fertilizer in your garden but be sure to dilute it with enough water. 

You can mix water and pee in the ratio of 20:1 (20 volumes of water and 1 volume of urine). Place the mixture in a watering can and apply it to the soil around the plants. Make sure that you don’t use the liquid directly on your crops. 

For Soil Enhancement

Since urine is also rich in potassium and phosphorous besides nitrogen, it can replenish the soil. Over-cultivating your garden can deplete the essential minerals which need to be replaced. Applying generous amounts of diluted urine in your garden can do wonders as far as enhancing the soil is concerned. 

Accelerating Your Compost

The process of decomposing vegetable matter into fertilizer for use in your garden may take a lot of time. You can add urine onto your compost to accelerate this process since it contains uric acid that helps break down materials constituting the compost. Make sure that you add enough undiluted urine to your compost.

For The Elimination Of Weeds

As mentioned earlier, urine consists of uric acid that kills plants if it comes into contact with them. This acid will not only be harmful to important crops but also weeds. You can apply this solution (undiluted) to any undesirable weeds in your garden to get rid of them.

It Balances The Amount Of Carbon In The Soil.

The soil consists of broken-down, dry brown materials such as leaves, sawdust, hay, and branches. These materials are high in carbon, but they break down very slowly. There are also green materials like vegetable peelings and lawn clippings which break down faster and provide nitrogen. To balance both brown and green matter and boost nitrogen content in your compost, you can add undiluted urine. Doing this helps in balancing the ratio of nutrients besides accelerating the breakdown of the matter. 

Deterring Animal Invasion

Human urine has a pungent smell that can deter wild animals from invading your farm. Animals such as deer, rabbits, cats, and foxes may not like the strong smell, which could act as a defense for your farm. You can therefore consider peeing in your backyard if you experience the problem of wild animals destroying your crops. 

Besides peeing in the garden, you can also fill a watering can or spray bottle with this liquid and spray it around your garden on bushes or trees where the animals can smell it. 

What Are The Benefits Of Using Urine As A Fertilizer?

Using urine as a fertilizer has several benefits, especially on maize, onions, and leafy green vegetables. These benefits include;

1. It is an excellent source of phosphorous, nitrogen, potassium, and trace elements essential for plant growth. 

2. It is non-toxic to plants besides being a body waste

3. The liquid is sterile when fresh and, therefore free from bacteria

What Does Human Urine Consist Of?

Human urine consists of about 95% water, and the remaining 5% is a mixture of salts, minerals, enzymes, hormones, and urea (around 2.5%). The following table shows some of these components and their percentages. 


Percentage composition (%)
UreaAround 2.5
Potassium 0.6
Uric acid0.03

How Can You Use Urine On Plants?

You can use urine in various ways, such as applying it in solution form to plants. Doing this helps to boost plants growth. Since urine is too strong to use undiluted on most plants, you can dilute it as follows;

1. Add 10-15 parts of water to 1 part of fresh urine and apply on crops in the growth stage.

2. Mix 30-50 parts of water and 1 part of urine and apply on plants sensitive to fertilizers and growing in pots.

Avoid using urine daily on your plants since too much of it could be harmful even when diluted. You can use this product on plants that require a lot of nitrogen, such as tomatoes, cucumbers, corn, and squash. Be sure to use it when these crops are in their fruit-bearing stage for better production. 

Urine is also advantageous to use on crops that show nitrogen deficiency, resulting in pale green and yellow leaves. Make sure that you don’t apply too much of this substance that would lead to excess nitrogen. Too much nitrogen may lead to your plants becoming bushy and leafy, which can attract aphids, and the plants may also bear fewer fruits. You can tell that your crops have excess nitrogen if their leaves become curled. 

What Are Some Health Precautions To Take While Using Urine On Crops?

Since urine is a bodily waste, you need to observe some health precautions when using it on plants. They include;

Avoid Contaminating The Liquid.

Ensure that the urine you use on plants is safe by preventing contamination with other body wastes such as feces. You can put your urine in a plastic jug or use special toilets that separate the urine and direct it to a storage tank. You may also store the solution in sealed containers for several months to reduce any potential pathogens. 

Do Not Use Urine From An Infected Person.

If a person is on medication or has a urinary tract infection, their urine should not be used on edible crops. But, one can use the urine on landscaping or lawns to prevent it from getting into contact with aquatic environments. 

Giving It Time

It will be safe to wait for a while (about one month) after applying the urine on edible crops before eating the same. It is also advisable to use your urine than other people’s to avoid infections if any. 

Storing Urine From A Group Of People

If you are mixing urine from a group of people, it is necessary to preserve it first since there are many chances of pathogens. Make sure that you store this product in a sealed container for six months before using it. You will also need to wait for another one month after applying on the crops before eating the same as an extra precaution. 

Be Extra Careful

You can use urine as a fertilizer on fruit-bearing crops such as cucumbers and tomatoes for social acceptability and safety concerns. You can also use it on perennials like trees and bushes with then use the leaves in a compost pile. You may also use the leaves as mulch since this is a socially accepted and safe method to cycle the nutrients back to the garden. 


While urine can kill plants if undiluted and if used in excess, it benefits the crops. Urine contains a lot of water which is advantageous to the crops, as well as essential nutrients. Using urine as a fertilizer will provide the plants with nitrogen, phosphorous, and calcium necessary for plants’ growth. 

When diluting the urine, it is vital to make sure that you add the right amount of water to prevent it from harming your crops. 

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