Disorder
Dog urine patches
Also called Dog urine burn, Urine scorch, Dog spots, Lawn burn
A brown circle the size of a saucer with a collar of lush grass around it. Nitrogen rather than acidity does the damage, so the supplements sold to fix the dog are the wrong answer and a watering can is the right one.
At a glance
- Type
- Disorder
- Cause
- Feeding or nutrients
- Severity
- Cosmetic
- Affects
- Garden plants
- Active
- All year
What you are seeing
- Roughly circular dead brown patches from the size of a fist to a dinner plate
- A collar of darker, taller, faster-growing grass around the outside of each dead patch
- Patches scattered where a dog squats rather than following any pattern in the ground
- Damage appearing within a day or two and always in the same few spots
- Grass at the edge of a patch needing mowing before the rest of the lawn
- Worst in dry weather and on a lawn that is already stressed
- Straw-coloured centres that stay bare unless the patch is reseeded
Before you treat anything
Do not give a dog a supplement, a food additive or a home remedy intended to protect a lawn. Anything that alters urine chemistry alters it for the whole urinary tract, and the acidifying products sold for this raise the risk of bladder stones. A lawn is not worth a dog's kidneys, and any change to diet or water intake belongs with a vet.
What you are looking at
Dead brown circles scattered across the lawn, each one somewhere between the size of a fist and a dinner plate, with sharp edges. Around every circle there is a collar of grass a shade or two darker than the rest of the lawn, thicker and taller, needing the mower before anything else does.
That green ring is the identification. Nothing else on a lawn produces a dead centre with a lush margin around it, and once you have seen it you will not mistake it again.
The patches sit where the dog stops rather than where the ground changes. They appear within a day or two of the event, and they turn up in the same few places, because dogs are creatures of habit.
Nitrogen, not acid
The story everyone repeats is that dog urine is acidic and burns the grass, and that female dogs are worse because their urine is more acidic. That account is wrong about the chemistry and wrong about the dogs.
Urine is mostly urea, and urea is nitrogen. A dog empties its bladder onto a patch of turf perhaps 20 cm across and delivers, in one go, several times the nitrogen that patch would get from a whole season of lawn feed. The grass takes it up faster than it can use it, the salt concentration in the soil rises past what the roots can draw water against, and the plants scorch and die. It is the same injury a spilled handful of granular fertiliser makes, arriving by a different route.
The green ring falls out of the same mechanism. At the edge of the wetted area the dose is diluted by the soil to something the grass can use, so it gets a feed rather than a burn. Dead in the middle, fed at the rim.
Female dogs do more damage than males for a reason that has nothing to do with chemistry. A bitch squats and empties the whole bladder in one place, and a male marks in small amounts against uprights. A male dog that squats produces the same patches.
What reduces it
The dose is the problem, so anything that spreads the dose out helps and anything that concentrates it hurts.
A watering can following the dog is the most effective measure available to anyone. A full can within a few hours takes the same quantity of nitrogen and distributes it through several times the volume of soil, and most of the scorch never happens. It is tedious and it works.
A dog that drinks plenty produces more dilute urine, so water bowls in more than one room, topped up, do quiet work all day. A lawn kept watered in summer has the reserve to absorb a dose that would kill drought-stressed grass. Mown long, it has more leaf and root to spread the load. And a gravel corner the dog has been trained to use removes the problem from the lawn entirely, which is where this ends up for most people who have both a dog and a lawn they care about.
Leave the dog’s chemistry alone
There is a shelf of products sold to stop dogs damaging grass, and they work by acidifying the urine.
Acidity was never causing the damage, so the premise is wrong before you get to the risk. Lowering urine pH increases the likelihood of calcium oxalate bladder stones, which cause a dog real pain and sometimes need surgery. Trading that for a tidier lawn is a poor bargain, and veterinary advice is consistently against it.
The same goes for tomato juice, cider vinegar and the rest of the home remedies. Change what happens to the urine after it lands, rather than what is in it.
What to do about it
Train the dog to a gravel or bark corner and keep rewarding it there.
Follow the dog out with a watering can and soak the spot within a few hours.
Keep fresh water available in more than one place all day.
Water the lawn through dry spells so it has the capacity to absorb a dose.
Mow higher and go easy on the lawn feed.
Reseed the dead patches with a hardwearing ryegrass mixture in spring or early autumn, after raking and pricking the surface over.
Flush a badly hit area for a few days before sowing into it.
Leave the dog’s diet, and any supplement aimed at its urine, to a vet.
What it gets mistaken for
Fertiliser scorch runs in stripes matching a spreader, or in a splash where the bag was tipped, and it has no green ring.
Red thread bleaches irregular patches to pinkish straw and threads them with fine pink strands, and the grass grows back on its own.
A fairy ring is metres across, expands every year and fruits toadstools in autumn.
Leatherjackets and chafer grubs kill the roots, so the turf rolls back like a carpet and birds tear at it.
Drought browns the lawn broadly and evenly, picking out the high ground and the thin soil rather than making circles.
What to do, in order
Start here
Prevention, and the changes that stop the problem returning. Most of these pages should end at this tier.
- Train the dog to one place
- A gravel, bark or shingle corner used consistently takes the problem off the lawn altogether. Take the dog there first thing, reward it there, and keep at it, because the habit is what does the work. This is the only measure that removes the problem rather than reducing it.
- Keep water in front of the dog all day
- The damage tracks the concentration of the urine, and a dog that drinks well produces dilute urine that the grass shrugs off. Fresh water in more than one place, topped up, and wet food rather than dry where the diet allows it, all reduce the scorching. Speak to a vet before changing a diet, since a dog with kidney or urinary disease has different needs.
- Look at the protein in the diet, with veterinary advice
- Nitrogen in urine comes from digested protein, so a dog on a very high-protein food produces more of it. This is a conversation for a vet rather than a change to make on the strength of a lawn, because protein matters more to the dog than the grass does.
- Water the lawn generally in dry weather
- A lawn under drought stress has no capacity to absorb a dose of nitrogen and burns where a well-watered lawn would only go dark green. The same dog on the same lawn does far less damage in a wet summer.
- Mow higher and feed less
- Long grass has more leaf and more root to spread the load, and it hides the green rings. Cutting back on the lawn feed helps too, since the urine is already delivering nitrogen and a fed lawn is closer to the point where it scorches.
- Sow a grass that takes it better
- Ryegrass and the fescues tolerate a dose of nitrogen better than bents and meadow grasses do. When you reseed the patches, use a hardwearing ryegrass mixture rather than a fine ornamental one, which also stands up to the dog.
- Ignore the supplements sold to change the dog's urine
- Products marketed to stop dogs burning lawns work by acidifying the urine, and acidity was never the problem. Lowering urine pH raises the risk of calcium oxalate stones, which is a serious condition, and it does nothing about the nitrogen that caused the burn. Vets advise against them and so does this page.
Then reach for a barrier
Netting, hand removal and water. Nothing here harms anything except the target.
- Follow the dog with a watering can
- Pouring a full can over the spot within a few hours dilutes the nitrogen through a much larger volume of soil and prevents most of the damage. It is the single most effective thing available, it costs nothing, and it works because the problem is concentration rather than chemistry.
- Repair the dead patches properly
- Rake the dead grass out, prick the surface over with a fork, work in a little fresh topsoil or compost, sow grass seed and keep it damp until it germinates. Do it in spring or early autumn. Scattering seed onto a bare dead patch without loosening it first rarely takes.
- Flush a badly affected area before reseeding
- Where several patches have run together, soak the area repeatedly over a few days to wash the salts down below the root zone before you sow. Seed put into soil that still holds the dose will germinate and then die.
Plants affected
Guides that name it among the problems to watch for. The list is the plants it is characteristic of rather than everything it will feed on.