Why Do Dogs Kill Grass When They Pee?

Adrienne Farricelli

Why do dogs kill grass when they pee? If you are looking for the ultimate weed killer, skip the nasty chemical Roundup and enroll the help of a dog instead. In no time, the weeds will wilt and turn an ugly yellow every time the dog hikes his leg and pees on them.

Sure, this natural remedy may work well if you are trying to get rid of unsightly weeds, but things may be a tad bit more upsetting if your dog pees on your beautiful, lush lawn creating ugly brown or yellow spots. So what's exactly in dog urine that makes it capable of killing the grass? Let's take a closer look at the culprits.

A Matter of Nitrogen

We often think of nitrogen being good to plants as it's sold as a fertilizer, but the saying "too much of a good thing" applies to fertilizers too. 

There are plenty of horror stories of people applying too much nitrogen and causing unsightly burns on the plant. In a desperate attempt, they may try to dilute the nitrogen with lots of water, but in some cases the damage is too much for the plant to handle.

When it comes to dog urine, it turns out, the problem is also a matter of nitrogen. According to Colorado State University, dog urine contains waste products such as nitrogen-containing compounds and salts which result in damage to lush lawns.

Method of Operation

The way your dog urinates may play a role in the amount of damage your lawn sustains. Is your dog a squatter or a leg lifter when it comes to peeing? 

Turns out, dogs who squat are more likely to cause more damage since they are likely to make a "larger deposit" compared to dogs who urine mark depositing small amounts of urine in various places and on vertical surfaces. And of course, the larger the dog, the larger the areas of dead grass.

However, don't give a sigh of relief yet if you own one of those pint-sized pooches who leaves tiny spit-like tinkles; should they use the same potty areas over and over, they are capable of damaging a lawn fairly quickly too!

The Big Old Myth

There are still some myths surrounding the effect dog pee has on grass. One of the most widespread has it that it's a matter of pH. The level of acidity or alkalinity of a dog's urine has really nothing to do with its ability to kill grass. 

A dog's urine is normally between pH 6.0 and pH 8.0, and these are levels that won't cause any harm to grass, explains veterinarian Dr. Fiona. The University of Wisconsin-Extension Network  therefore claims that it's pointless to give dogs acidifying agents such as tomato juice or vinegar for the purpose of adjusting the levels of pH of the dog's urine when the main culprit is the nitrogen as explained above.

Skip these Remedies! 

Since the levels of concentrated nitrogen in dog urine are the main culprit for those unsightly brown spots, it may make sense to feed a dog salt to encourage him to drink more so that he produces more diluted urine.

Unless you want a lush yard and a potentially sick dog, you may want to skip this potentially harmful practice. Salt in excessive quantities can be dangerous to dogs. The Pet Poison Helpline lists salt as quite poisonous to dogs and cats and it can cause problems to a dog's kidneys and heart.

Baking soda, potassium citrate and products containing methioform or other salts are also potentially harmful. "There are no dietary supplements that have been scientifically proven to reduce either the incidence or severity of dog spotting in lawns," warns the Colorado State University Extension website.

Play it safe and avoid giving any supplements or altering your dog's diet without discussing any changes with your vet. There are fortunately safer options to reduce those unsightly lawn spots caused by your dog's urine.

Now That You Know...

My dog's urine is killing my grass, what can I do? Countless dog owners are looking for solutions to this common problem. Here are a few options to find a compromise.

How to Prevent Brown Urine Spots on Grass

  • Dilute the urine. After your dog urinates, hose down the area so that you dilute the urine preventing it from causing damage. Dr. Allard's study showed that a fertilizing effect rather than harmful burn was attained when the urine site was watered at any time up to 8 hours after urination! How about that?
  • Another way to dilute the urine is by encouraging the dog to increase water intake. Always provide access to clean, fresh water. Moistening dry food with water or giving canned food are other options, but best to consult with the vet first before making any drastic changes.
  • Feeding premium dog foods that provide higher quality protein that's more readily digestible may be helpful, further suggests Dr. Steve Thompson. As always, best to consult with a qualified dog nutrition expert for suggestions.
  • Train your dog to go potty on cue in a specific area. Choose a spot where you don't care about any unsightly brown spots or create a potty area where there is gravel, dog-safe mulch or a more tolerant grass.
  • Grow a type of grass that is more resistant to the effects of nitrogen. Choose perennial ryegrasses and fescues over the delicate Kentucky bluegrass and Bermuda.
  • For dogs who repeatedly urine mark on bushes, young plants or vines, the use of a marking post under the form of a bird bath, lawn ornament, big rock or fake fire hydrant may encourage marking on these vertical objects instead. Praise and reward your dog for using these.
  • Last but not least, simply accept those brown spots and get over it. Dogs are much cooler than lawns, who cares if a yard looks a bit funky? Dogs are so totally worth it! Woof!

Did you know? The content of nitrogen in a dog's urine is due to the breakdown of protein through normal bodily processes, explains Dr. Steve Thompson, veterinarian and Director of Purdue University Veterinary Teaching Hospital Wellness Clinic in West Lafayette, Indiana.


Allard, AW. Lawn burn and dog urine, Canine Practice, March/April 1981;8;(2);26-32.

Colorado State University Extension Horticulture Agent, Larimer County; and Tony Koski,PhD, Extension Turf Specialist, Department of Horticulture & LA, Colorado State University

The University of Wisconsin-Extension Network: Lawns and Dogs But Not Tomato Juice, Courtesy of Diana Alfuth, Horticulture Educator, Pierce County UW Extension

Texas AgriLife Extension Service, Aggie Horticulture, Dog On It Lawn Problems, by Dr. Steve Thompson, DVM - Director Purdue University Veterinary Teaching Hospital Wellness Clinic