Does Deer Urine Kill Grass?

With the ability to jump 6-foot fences and an average weight of 225 lbs, deer can cause a lot of damage to your lawn. They’re hard to keep away and once they find somewhere to graze, it can be difficult to discourage them from coming back night after night. While the grazing itself might not cause much harm, the resulting urine and hoof damage can add up, but will it outright kill your lawn?

Does Deer Urine Kill Lawn Grass?

Yes, deer urine can kill lawn grass. Deer urine is highly concentrated and, given the size of the animal, they can produce a lot of it. While a little deer urine or diluted deer urine wouldn’t be a problem, the amount the average deer produces over a small area will cause dead, discolored spots on your lawn.

The best thing you can do to combat this problem, especially if you have deer visiting night after night, is to find a way to keep them off of your lawn. Deer, however, are both stubborn and resilient. Below are a few suggestions on how to deal with this problem.

How Do You Prevent or Treat Deer Urine on Grass?

Yes, deer urine can kill your grass very quickly. However, you can also take a few preventative steps that will make your lawn less susceptible to death via deer pee. Preventing or discouraging deer from coming onto your lawn is another option.

How to Make Your Lawn More Resilient to Animal Urine

There are 3 primary ways to improve your lawn and make it more resilient against all types of animal urine.

• Run the Sprinklers – The first and perhaps the easiest solution is to run the sprinklers for a few minutes several times a night, particularly 2 hours after sundown and again just before dawn. Deer are most active just before these hours, making this an ideal time to flush the urine further into the ground, wash it off the grass, and dilute the nitrates to more manageable levels.
• Plant a Grass Type That Needs More Nitrogen – Fescue, Zoysia, and Ryegrass are all grass types that need more nitrogen access than other types. This means they can handle the direct application of nitrogen-rich urine much better than grasses like St. Augustine or Bermuda.
• Fertilize Your Lawn Less – If you have deer visiting your lawn every night, you may want to back off on applying additional fertilizer that contains nitrogen. This can help prevent over-fertilization.

Ways to Discourage Deer from Visiting Your Lawn

If the methods for dealing with the urine itself aren’t working, it may be worth trying to prevent the deer from visiting your yard altogether.

• Put Up a Barrier – The most effective way to deal with deer is to put up a high, solid fence. A straight fence should be 8 feet tall to keep the deer out. Alternatively, some people have had success putting up a 5-foot fence with an additional 2- to 3-foot section of lightweight deer ribbon or mesh along the top. Electric fences are also effective against deer and many are easy to install. A 6-foot fence can also work if an outward “roof” or slant is added to the top. This type of fence is also a recommended deterrent against foxes, squirrels, and raccoons.
• Scare Tape, Owls, and Flashing Lights – Any motion-activated or security light will be ineffective against deer. The same is true of warm and red-colored lights. Deer have trouble seeing light on the red spectrum. The most effective lights when it comes to deer deterrents are blue, cool, and flicker when they sense motion. Scare tape placed in the vicinity of a standard security light can also make these more effective. Motion is the most effective deterrent, along with loud and sudden sounds.
• Smell Deterrents – Irish Spring, Coyote urine, and human hair are all smell-based deterrents commonly said to keep deer out of an area. However, all evidence for any of these methods is only anecdotal.
• Sound Deterrents – Sonic Pest Deterrents may say they work on deer, but this is not true. The wavelengths of the “sonic” sounds are in the 20-kilohertz range. This is why they are inaudible to humans. However, they are also inaudible to deer. Most deer can hear sound in the 2 to 6 kilohertz range, with some being able to hear sounds outside of this range but not well or consistently.

Will Deer Urine Kill Grass and Weeds Permanently?

Similar to the urine of dogs or foxes, deer urine is potent enough to kill grass. The reason, in short, is that deer urine is high in nitrates. While nitrates do contain nitrogen, too many nitrates in a concentrated solution can overwhelm your grass in a similar way to over-fertilizing it with commercial nitrogen-based fertilizer.

The good news is that while this sudden dose of nitrogen can sicken your lawn, it won’t kill the grass altogether in most cases. If it does, you can reseed the area right away. On the flip side, this also means deer urine won’t kill weeds and, depending on the type of weed, may even make them grow a little better.

Brown Spots on Your Lawn But No Dog? It Could Be Deer

Unless you already have one of the fence types described above, brown spots in your lawn not caused by a house pet are likely caused by deer. Not only that, but if you have deer urine spots, you may be missing as much as 7 lbs of landscape foliage per deer per night.

The deer population in the US currently sits at an estimated 33 million with an increase of about 500,000 deer per year. Fences are the only defense system that has been proven to keep them out. If deer are a problem in your area and look like they’re there to stay, consider the management options outlined above: water frequently in the early morning hours, build a fence, or plant grass that is better at dealing with deer urine.