Theories abound about what in dog urine is toxic to plants, a popular one being extremes of pH. People say that acidic urine burns the plants, but the real answer to “Why does dog pee kill plants?” is a lot simpler.
A 1981 study called Lawn burn from dog urine helped bury the old myth that pH is causing the trouble. The concentration of urea in dog urine is basically too much of a good thing for grass and other plants. Other salt and compounds such as potassium may also contribute, but nitrates are known to be the No. 1 killer.
The main thing that makes dog urine more damaging is volume. Large dogs deposit more urine. Females tend to deposit it all in one location. Male dogs are easier on the grass but hard on trees, where urine sprayed on the trunk can filter down to the roots and in large enough volumes can kill the entire plant.
Just how much dogs contribute to the poor health of some city trees is under debate. But we’ve all seen the grates, bags and other contraptions to try and keep the trees pee-free.
You can use training to modify behavior, getting your dog to pee in certain areas and to use the gutters rather than the grass. But most dog owners draw the line at being quite that prescriptive. So there are a number of other tips to reduce the conflict between pup and gardens.
Focusing all the dog pee in one spot can help with the problem … if you give up putting any plants in that area. A stake in an out of the way area may attract males to use the area. Likewise, when you are out and about, if your dog will use mulched or graveled areas, this will reduce stress on plants.
Of course, a dog’s gotta go when a dog’s gotta go. But when you have the option, steer Fido to a lamppost rather than a tree and a bark covered area rather than a stressed-looking lawn.
You can spot stressed trees by bark that is discolored or even peeling off around the base. And trees that are under six inches in diameter or have thin bark are at higher risk.
If you can, watering the peed-on area immediately can help dilute the urine and minimize plant damage. For similar reasons it is a good idea to ensure your dog always has ample access to water. More diluted urine will do less damage. And besides, who wants to have a dehydrated doggie?
Various potions are on sale to break down the ammonia even more effectively than water. So if you have an especially cranky neighbor and your dog just really has to go on his property, you might consider carrying a squirt bottle of pee-weakener on your walks to minimize the damage. If your local stores don’t have it, you can order it online in tablet form and make the solution up as needed.
I am not sure how well they work, but at least they show you are making an effort. And when it comes to your more ardently gardening neighbors, I think dogged kindness and consideration is a better approach than engaging in a pitched argument.
If you are establishing or replacing a lawn, look into more robust grass species. Most lawns use something like Kentucky bluegrass, which has shallow roots and is easy to transport and establish. But it is also one of the more sensitive varieties and easily damaged by urine. Bermuda or ryegrasses may be more difficult to establish but they are hardier once they settle in.
I personally am not in favor of putting anything inside a dog that doesn’t need to be there. But I suppose it is possible that supplements that bind nitrogen are completely safe for dogs. I draw the line just short of this particular solution, but others may wish to look into it.
I would recommend making sure that you know exactly how the additive works and taking veterinary advice about its use with your dog. And I would immediately disregard any products aimed at changing the pH of the dogs urine because, as we have already established, this is not the cause of the problem.
The community balance of dog versus plants tends to become particularly fraught in built-up city areas. I remember once being reprimanded at length by an elderly neighbor just because my dog was peeing in the grass around my apartment building. It is the only building for miles that allows large dogs and as a result contains quite a few of them. The grass, I concede, is less than thriving.
I decided to simply not reply (despite her real fur coat giving me some tempting material for a rebuttal) and a few days later the same woman actually walked up to me and apologized. She just wanted the environment to look nice and knew that I wasn’t doing anything thing deliberately to damage it.
Whether you are more of a dog person or more of a plant person, or a bit of both, it is always a good idea to try and reduce conflict where we can and make the community a great place for both puppies and plants.
About the author: Emily Kane is a New Zealand-born animal behaviorist of the throw-back radical behaviorist type, albeit with a holistic-yuppie-feminist-slacker twist. She spent many years as an animal behavior researcher and is now more of an indoor paper-pushing researcher. Her early dog-related education came from Jess the Afghan Hound and Border Collies Bandit and Tam. It is now being continued by her own dogs and extended dog family and some cats (and her three aquatic snails Gala, Granny, and Pippin — they think of themselves as dog-esque).
Thumbnail: Photography by Heinz Teh / Shutterstock.
This piece was originally published on October 6, 2013.