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Peeing In The Garden: Does Human Urine Kill Grass?

There are several reasons why human urine can kill grass. However, these hazardous and potentially deadly characteristics that kill plants and grass only apply to undiluted human urine. Properly diluted human urine can act as a sort of fertilizer and won’t actually cause any harm to your grass.

Did you know that human urine has multiple uses in the yard and garden? Surprising, I know! But it’s a practice that’s been used across many generations of farmers and gardeners across the world. There must definitely be something worthwhile exploring here since the practice of applying this liquid gold substance to grass is still used to this day.

However, as with any good DIY concoction, you need to make sure it is safe to use by doing your research and following careful instructions. Fear not – I’ve detailed everything you need to know about using human urine on your grass in this article. Keep reading to find out more!

Purposes Of Human Urine In Gardening

Human urine can be used for several garden and yard purposes. These are the most common:

  1. Lawn fertilizer
  2. Animal deterrent
  3. Soil enhancer
  4. Weedkiller
  5. Eliminator of fungal diseases
  6. Compost accelerator

However, remember that human urine will only work for these purposes if it’s diluted well. 

Check out this video by YouTube user Project Diaries for an in-depth explanation on how to use human urine as a fertilizer:

What Does Human Urine Do To Grass?

Peeing In The Garden: Does Human Urine Kill Grass?

Human urine can have both benefits and harmful effects when applied on grass and around plants. The effect it has depends on what it is made up of. So, factors such as where, when and from whom it was collected are important in figuring out whether it’s going to kill plants and grass or have nutrient properties and amino acids that promote healthy lawn growth.

Human urine can have harmful properties if its composition is altered by prescription drugs, dehydration, high sodium levels, and if it’s used full strength. This is because these substances can alter its pH, making it incompatible with the requirements of grass and soil.

patch of dried grass surrounded by healthy grass

Surprisingly, human urine can also have very useful properties, and grass and plants generally respond well to being treated human urine as a sort of fertilizer, a practice that’s been used by farmers and gardeners for ages. 

The trick here is that it needs to be from a healthy source, low in sodium, and have a high water content in order for it to be safely applied to grass and plants. 

It isn’t going to be easy to ensure that the urine you may want to use isn’t harmful, so it’s always best to be on the safe side and dilute urine with some water. Applying undiluted urine to grass may cause a build-up of the urine’s substances in the soil, which will hinder growth and lead to burnt and dead grass and plants around it.

On the other hand, applying diluted urine will give your grass and plants a healthy dose of beneficial nutrients, such as phosphorous, nitrogen, potassium and uric acid. Uric acid is the most beneficial because it helps eliminate diseases, downy mildew and mold. It will also speed up the decomposition process of any dead plants.

You’ll find that human urine will have the highest concentration of uric acid when it’s released by its source first thing in the morning or if the source is dehydrated.

While having uric acid present in human urine can be beneficial, it can also harm your grass and plants if undiluted. However, if you’re looking to rid your garden of weeds or pampas grass, and restrict the growth of grass beneath your fence and in between paving stones, human urine can definitely help!

Cleaning Up Urine From Grass

Spraying water over grass

Found yourself in a bit of a fix and now your lawn has urine all over it? Well, if it isn’t diluted, you’re going to want to clean the affected area as soon as possible to make sure your grass and plants don’t suffer any harm.

But how do you even remove urine that’s already applied to grass? It’s not like you can mop it up or vacuum it out the soil! Your only option to save your grass and plants is to dilute urine. I know, it’s not ideal, but the only way you can do this is to water your garden so that the urine loses its pure concentration.

How To Safely Apply Human Urine To Grass

A water can on a lawn

You will first need to dilute the human urine to ensure that it is actually safe for the grass and plants around it. It’s difficult to set actual measurements or a “recipe” as such for this (unless you have the time and are prepared to test the urine using pH strips to check its levels of uric acid, nitrogen, phosphorous and amino acids). 

However, if your source of the urine is a healthy and well-hydrated person, the ideal ratio to dilute it would be 20:1, meaning 20 parts water to 1 part urine. You can start by adding water to a bucket and then adding the human urine to it.

Once your diluted concoction is ready, you’ll be able to apply it to your grass. You can fill up a spray bottle which you can use to apply it directly onto the grass. A suitable time to apply it is early in the morning before the dew has evaporated. This is because the dew will help further dilute it, as well as prevent the solution from sticking to the blades of grass. 

If you plan to use human urine as a fertilizer, make sure you don’t use any other plant fertilizer in conjunction with it. This may result in you giving your lawn a double dose of nutrients, and adding more nitrogen and phosphorus will definitely do more harm than good. 

A double dose of these substances will hinder the growth of your grass and plants, generally speaking. This is because it will cause a build-up in the soil. A build-up of nutrients such as nitrogen, potassium and phosphorus will alter the soil composition, and result in a bare patch where no grass or plants will grow. 

While you should definitely steer away from it if you’re looking to grow in that area, it’s definitely a good option to try out for a nutrient-dense compost pile.


Is Urine Bad For Lawn?

Urine is bad for lawn when it is undiluted and concentrated in a particular area. This is because its contents can be too strong for the grass, causing a type of fertilizer burn. However, diluted human urine can be useful for several purposes due to its nutrient content.

Does Human Urine Help Grass Grow?

Human urine does help grass grow because it contains beneficial nutrients that are typically found in commercial fertilizers. However, the urine needs to be diluted so that there isn’t an over-concentration of substances, which can harm grass.

Can You Use Urine To Kill Weeds?

You can use urine to kill weeds. Human urine contains uric acid, which is known for killing weeds. It burns and breaks down most plants upon contact. Human urine is typically high in uric acid first thing in the morning from a hydrated source or from a dehydrated source.

So, Does Human Urine Kill Grass? Yep!

Now that was quite an intense one! While using human urine is common for some, it’s also an unknown phenomenon for others (like me!)

I remember first coming across the harmful effects of dog urine once when my dog was on prescription medication. It was not pretty, so please exercise caution if you’re interested in using human urine to grow a healthy lawn! The impact of urine from humans and dogs is pretty much the same.

I hope you found this article helpful and that I helped answer your question. Please let me know in the comments below. We’d love to hear from you!

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About The Author

Nadya Jones

Nadya is a writer, entrepreneur, and designer based in Raleigh. She writes in her blog, the one you are visiting right now, where she shares her love for landscaping, gardening, and outdoor design. Her husband Brett provides her with a lot of inspiration and behind-the-scenes content. Together, they work on creating beautiful outdoor spaces that serve as an extension of their home and inspire others to do the same. If you are interested in landscaping, gardening, or outdoor design, be sure to check out the blog! Also, follow Nadya on Twitter, Instagram, Pinterest, and Flickr!

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