Have you ever noticed that one patch of grass in your garden that's inexplicably dry or burned? Ever wondered how it got there? Here's a hint. Watch where your dog goes to the toilet. Is it in the spot with the dried up grass? Bingo! Guilty as charged. Don't own a dog? Look to your neighbors.
These brown spots happen because dog urine is rich in nitrogen, which is known to kill grass where concentrated amounts collect.
It is a common misconception that "acid" in a dog's urine is what causes the brown spots left behind on our lawns. However, the culprit causing lawn burn is actually the high nitrogen content of the dog's urine. This nitrogen is "the waste" in the urine and is the result of protein breakdown through normal body processes. Because a canine diet is very high in protein, there will be high levels of nitrogen, and you'll be battling blemishes for as long as your or your neighbor's dog uses the lawn for its place of business.
The effects of dog urine on your lawn are similar to that of a nitrogen-rich liquid fertilizer. A small amount of fertilizer makes your yard healthy, but too much will kill your lawn. There are many home and commercial remedies that promise to correct this problem, but most of them are ineffective and a few of them can actually make the situation worse for your lawn or negatively affect the health of your dog. I will describe factors that contribute to lawn burn and give a few recommendations for preventing this problem in your own yard.
But first let's bust the myth that only female dog's pee causes brown spots in your lawn. Female dogs are more likely to cause lawn burn than males because females void their entire bladder in one location by squatting instead of lifting their leg and marking, like males. However, some male dogs squat like female dogs and therefore can be the guilty party.
Large dogs deposit more urine so they increase the quantity of nitrogen in one location, making lawn burn more likely. And dogs fed a very high protein diet are more likely to produce a urine that causes lawn burn.
Heavily fertilized yards are already receiving near maximum levels of nitrogen. The additional amount of nitrogen in dog urine may be all that is needed to put these lawns over the edge and cause turf burn. And lawns that are stressed are more susceptible to damage. Lawns that are suffering from drought, disease, or are newly sodded or seeded are more susceptible to turf burn. Ryegrass and fescue grasses are the most urine-resistant type of grass, while Kentucky bluegrass and Bermuda are the most sensitive. Buffalo grass also is sensitive.
But before you start implementing changes to correct lawn burn, you need to make sure that a dog is actually the culprit. Several lawn diseases can look like lawn burn, causing small, characteristic brown patches. First, make sure that the brown spots are in areas where you suspect a dog urinates. Most dogs will have an area in the yard that they choose to use over and over again when they relieve themselves. Unfortunately, your neighbor's dog usually prefers to pee in other's yards. Make sure that the grass in the brown spots is still firmly attached. Grab a handful and give it a steady pull. If the grass is firmly rooted, that points to lawn burn. If the whole bunch of grass pulls up, roots and all, then you may be dealing with a white grub problem.
"Dilution is often the solution to pollution," a concept that holds equally true in the case of urine scald on our once green lawns. Therefore, the best way to help prevent brown spots from developing is either by dilution or by addressing the external environment. Pouring water on the area after your dog urinates will help to dilute the urine and lessen the effects of the nitrogen on your lawn. You can also encourage your dog to drink more water. The more your dog drinks, the less nitrogen will be concentrated in the urine and the less damaging it will be to your lawn. It will also be healthier for your dog as well. You can also train your dog to pee in a less problematic area. What about your neighbor's errant dog? That's a different matter and I refuse to go there.
Jim Leser retired to Cedaredge in 2007 after a career with Texas A&M University Extension in entomology. He is a member of the Cedaredge Tree Board and a Colorado Master Gardener.