Is Cat Pee the Secret Fertilizer Your Plants Need?

Having a beloved feline companion can bring great joy, but cat owners who also maintain a garden may wonder if their cat’s bathroom habits could pose a risk to their plants. While the idea of cats relieving themselves in houseplants or vegetable patches may seem unpleasant, the actual effects are likely less harmful than many assume.

Cats will naturally seek out loose, soft soil to bury their waste, and this instinct can lead them right to the flowerbeds or vegetable garden. Though no pet owner wants their cat to view their yard as a litter box, the occasional accident may leave some concerned about potential toxicity or other dangers to their greenery.

However, research indicates cat urine and feces, while carrying some risk, are generally not as detrimental to plant life as commonly believed. With proper handling and sanitary practices, gardens can thrive alongside feline friends.

Overview of Cat Urine Composition

Cat urine consists of several compounds that give it its characteristic odor. The main components are:

    a cat urinating on a houseplant

  • Ammonia: Produced when bacteria in the gut break down urea and proteins. Ammonia has a strong, pungent odor that contributes significantly to the smell of cat urine. High concentrations of ammonia can be irritating and potentially toxic.
  • Uric acid: The end product of purine metabolism in cats. It forms crystals and contributes a bitter, acidic odor to urine.
  • Phenyl derivates: Cat urine contains high levels of phenyl compounds like felinine and 3-mercapto-3-methylbutan-1-ol (MMB) which give it a distinctive odor. Cats have a gene mutation that allows them to produce phenylalanine which converts to these smelly compounds.
  • Volatile organic acids: Compounds like acetic acid, propionic acid and butyric acid that have a vinegar-like smell.
  • Sulfur-containing compounds: Substances like methyl derivatives of thiols that have a sulfurous, rotten egg odor.

In addition, the relative concentrations of these compounds in cat urine varies based on age, sex, diet and health of the cat. This affects the intensity and specifics of the odor produced.

Potential Effects of Cat Urine on Plants

Cat urine contains high levels of nitrogen, which can act as a fertilizer for plants in small doses. The nitrogen in cat urine comes from proteins and amino acids like urea and uric acid. According to research, urine can provide over 90% of the nitrogen, 60% of the phosphorous, and 75% of the potassium needed for crops. [1]

However, in larger quantities, the nitrogen and salts in cat urine can quickly build up and burn plant roots, leaves, and stems. Cat urine is more concentrated than human urine and the high ammonia content is particularly damaging. Ammonia absorbs moisture from plant tissues, causing them to dry out. The salts in urine also change the pH balance of the soil, harming microorganisms. [2]

Additionally, cat urine may contain microbes like bacteria and viruses that can infect plants. Common feline urinary tract infections include Chlamydia, fungi like Aspergillus, and Calicivirus. Overall, while a small amount of nitrogen from cat urine may benefit plants, too much cat urine can harm or even kill vegetation.

Toxicity Concerns

While cat urine does contain potentially harmful substances, it is generally not a major health threat to humans at typical exposure levels. However, there are some toxicity concerns to be aware of:

Uric acid, a normal component of cat urine, can potentially cause health issues at very high concentrations. But regular exposure to cat urine does not typically reach toxic levels for healthy humans. Only those with severe allergic reactions or immunodeficiencies may experience adverse effects from ambient urine exposure [1].

Diseases are not directly transmitted through cat urine. Toxoplasmosis, a disease caused by a parasite in cat feces, does not spread through urine. However, urine may contain trace amounts of feces that could potentially transmit toxoplasmosis if ingested. General hygiene practices should prevent any transmission [2].

While high ammonia levels from cat urine can cause headaches and asthma attacks, typical household levels are unlikely to cause major issues in healthy individuals. Proper litter box maintenance and home ventilation can prevent buildup of concerning ammonia levels [3].

using an enzyme cleaner to remove cat urine from soil

Tips for Gardening with Cats

If you want to garden while owning a cat, there are some tips to follow that can create a safe outdoor environment for both your plants and feline friend.

One suggestion is to place plants that are less sensitive to cat urine closer to litterboxes or areas your cat frequents for urination. Plants like lavender, rosemary, catnip, and cat thyme tend to hold up better against cat urine. Keep your more delicate plants further away from prime cat urine zones.

It’s also a good idea to water the soil after your cat urinates. This helps dilute the urine and minimize damage to plant roots and leaves. Water thoroughly wherever your cat goes to the bathroom outside. You may want to consider creating designated urination areas in your garden using sand or soil patches.

With some planning, you can have an outdoor space that both you and your cat can enjoy safely.

Cleaning Up Cat Urine in Soil

If cat urine has soaked into your garden soil, you’ll need to take steps to remove and replace the soiled areas. Here are some effective methods for cleaning up cat urine in soil:

Remove and Replace Soiled Soil: Dig up any soil that smells like cat urine or appears discolored. Remove the affected soil and replace it with fresh, clean soil/compost. Discard the soiled soil far away from your garden.

Use an Enzyme Cleaner: Enzyme cleaners contain bacteria that break down the compounds in cat urine. Saturate the soiled areas with an enzyme cleaner like Nature’s Miracle. Let it soak in for 10-15 minutes before rinsing thoroughly with water.

Vinegar and Baking Soda: Mix together 1 part white vinegar with 1 part water. Sprinkle baking soda generously over the affected area and pour the vinegar solution over it. The vinegar and baking soda will react and bubble up. Let it sit for 15 minutes before rinsing away.

By promptly cleaning up cat urine accidents in garden soil, you can help eliminate odors and prevent damage to your plants.

Preventing Cat Urinating in Gardens

putting citrus peels around a garden to repel a cat

There are several steps cat owners can take to prevent cats from urinating in the garden.

First and foremost, be sure your cat has access to a clean, regularly scooped litter box. Cats have an instinctive need to dig and eliminate in soft or sandy areas, so providing litter boxes around the house and yard can satisfy this urge. Scratching posts are another outlet for digging behaviors. Place scratching posts near areas the cat tries to dig.

Natural repellents like citrus peels can also deter cats from urinating in gardens. The strong citrus smell is unpleasant for most cats. Try scattering lemon, lime or orange peels around the perimeter of the garden bed. Coffee grounds, vinegar, essential oils like lavender or eucalyptus, and tobacco powder are other natural scent repellents to experiment with. Always monitor the cat’s behavior and stop using any product that seems to agitate or harm the cat.

For sources, see:

When to Be Concerned

While small amounts of cat urine are unlikely to seriously damage most plants, keep an eye out for signs of excessive exposure. Watch for brown, burned patches or spots on leaves and stems, which can indicate concentrated urine in one area. Also note any major changes in plant health, like wilting, yellowing, stunted growth, or leaf drop. According to experts, these could signal potentially toxic levels of cat urine exposure (cite: If you notice these warning signs, act quickly to flush the soil and consider repotting the plant with fresh potting mix.

Repeated cat urination in the same spot can create high ammonia levels that burn and damage plants. Pay special attention to delicate herbs and vegetables you plan to consume. Research indicates cat urine could potentially transmit parasites through contaminated soil, although the actual risk is debated (cite: When in doubt, don’t eat plants that have been directly exposed to cat urine.

wilted vegetables plants affected by cat urine


In summary, while cat urine does contain compounds that could potentially harm plants in large quantities over time, occasional exposure to small amounts is unlikely to cause severe damage. The main risks come from the nitrogen and high acidity in cat urine, but proper soil maintenance can mitigate negative effects. Furthermore, cat urine can provide some benefits as a nitrogen fertilizer when applied correctly in moderation. With some precautions like repellents, barriers, and training, cat owners can comfortably garden while safely coexisting with their furry friends.

The takeaway is that cat urine’s impact depends greatly on the dosage and application. With some care and planning, gardens can thrive alongside feline companions. Perhaps in the future, science will unlock even more potential for this timeless natural fertilizer.


DimMarie. (2020, May). Cat urine stains in soil- safety, eradication, and problems it causes. Garden Lovers Club.

Palmer, T. (2021, February). Will cat urine hurt plants? Hunker.

Ossola, A. (2019, June). Your cat is ruining your plants. But it’s not too late to fix your dirt. Popular Science.

Staff, T. (2020, September). What happens if your cat pees on your plants? Treehugger.

Warren, L. (2020, August). Will cat urine kill plants? Greenthumb Planet.

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