Pets (particularly dogs) are the most frequent cause of patches of darker green and/or brown turf, that are often concentrated in a particular part of the lawn.   Animal urine contains highly concentrated salts and nitrogen that dehydrate the turf.

Animal urine can damage any turfgrass species in any climate.  The most severe damage seems to occur where soil moisture is low and turf is poorly hydrated. Prolonged dry, hot weather may exacerbate the damage.   In severe cases of urine damage, turf receiving the highest concentration of urine typically takes on a gray-green, wilted appearance, which rapidly turns straw brown (Figure 1). Turf death may occur in 24 hours or less in hot, dry conditions. Dead patches of turf do not always appear, but when they do, there is a central crater of brown turf, 3-6 inches in diameter, surrounded by a dark green ring, 6-12 inches in diameter (Figure 2).  This combination of very green and dead brown patches may persist for several weeks depending on the vigor of the surrounding turf and its capacity to recover and fill in.  Furthermore, urine damage almost always has a dark green, actively growing perimeter.

Of the common household pets, dogs tend to damage turf most.   Among dogs, females are more of a problem than males, due to differences in voiding behavior.  Females typically squat when they urinate and male dogs lift their legs.  However, young dogs of both sexes normally squat to urinate and the typical leg lifting and marking behaviors of male dogs do not become prevalent until dogs are about 1 year old.  In addition to squatting, female dogs are less discriminating about where they void and typically release all of their urine in one concentrated location.

The only way to ensure animal urine does not damage turf is to completely remove the pet from the lawn, which for most pet owners is simply not practical, so consider the following management practices:

1. Keep the pet off the most visible parts of the lawn and/or train the dog to use one designated low-visibility area.

2. Water the portion of the lawn where the dog has voided with a watering can. This helps minimize serious damage but may not completely eliminate a greening response.

3. Walk your pet in a neighborhood common area, dog park, or other, less aesthetically important turf area.

4. Maintain healthy, vigorous turf that can easily recover from damage.

Although the turf affected by pet urine may respond to urine nitrogen, this does not necessarily mean that the lawn requires fertilization.  Modest nitrogen additions may mask urine symptoms but nitrogen should only be applied when it will benefit the turf, and not during times when the turf is dormant and nutrients will be lost to the environment.

Some commercially available products claim they can repel animals from urinating on particular areas.  However, these products have not been proven to be effective.  Also, a number of self-proclaimed pet authorities suggest a variety of dietary modifications (usually in pill form) to manage animal urine turf damage. Some products purportedly manipulate urine’s nitrogen content or affect the animal’s liquid consumption. Most of these products simply cause the pet to drink more water, thereby diluting the urine’s nitrogen content.  Furthermore, using these products is potentially dangerous, and you should consult a qualified veterinarian before initiating such a remedy.