There are many potential causes for a patchy lawn and dying areas of grass. Brown patches on your lawn can be very unsightly and can cause significant upset if you are an avid gardener. There are a number of reasons why this could be happening, but most of them are relatively easy to fix, so do not worry.
Why Is My Grass Dying In Patches
Fungal problems
Patches caused by a fungus will often appear Brown and irregular in size and shape. You may even notice an area of seemingly healthy grass surrounded by a ring of Brown. This is common if the fungus has been allowed to run rife for an extended period, as the interior of the area has begun to recover.
Fungal issues can be exacerbated by periods of heavy rainfall or intense humidity. This increases the moisture content of the soil and provides the perfect environment for fungi to thrive.
Here in the Uk, fungicides for domestic use are somewhat limited, but you can access a few. “Provanto” is one of the more well-known ones. It can be found here on Amazon (affiliate link) These are added straight to the soil to protect your plants against current and future fungal infections.
How to apply a fungicide to your lawn
- Wait for a dry day (and make sure the grass isn’t left too long, or too short (around 1.5 to 3 inches is fine)
- Mix and spray / apply it onto the grass as directed, then leave to dry
- Do not mow the lawn for at least 3 days after treating.
Bugs / Grubs
Bugs are the bane of any gardener’s life, particularly chafer grubs, and leatherjacket grubs. These are the young form of scarab beetles like June bugs, Japanese beetles, and European Chafers.
They consume organic matter in the soil and feed on the roots of your grass to survive. This can eventually lead to patches of your grass dying off as they can no longer uptake nutrients. I have seen several lawns that have literally been entirely devastated.
If the patchiness is caused by grubs, you will notice Brown areas. The area will have a spongy texture. Reach down and grab a piece of grass and give it a tug. If the grub problem is severe you will be able to lift up the turf like a carpet.
It also makes sense to check your soil once a month. Use a sharp spade, dig down 6 to 8 inches. Cut a square and tease out the piece of turf. Gently thumb through the soil without breaking it up too much to inspect for any grubs in the lawn.
Note that lawns can tolerate a few grubs, if they are healthy, however, if there are significant numbers you are looking at problems that need fixing.
Even though your lawn is under stress, as soon as the birds become aware there are grubs in the lawn they will be down all the time, lifting up the turf and tossing it aside to get to the grubs. This is where the most devastation comes from.
How to treat chafer grubs and leatherjacket grubs
Treatments are more limited than what they used to be years ago (most pesticides are now banned). There are 2 main ways to treat grubs.
- Using nematodes (affiliate link) (will require daily watering for 2 weeks, and ideally a good forking or aeration beforehand), or..
- You can use some Turfsolv. Turfsolv is a personal favourite of mine. Simply measure your lawn, apply as directed, and repeat once a month. It also helps the lawn from a variety of other stresses such as Disease and ants!
To fix any bare patches in your lawn, you should rake up all of the dead grass, scatter a thin layer of seed then a thin layer of topsoil over your seed, firm down and water regularly.
Ants
Ants can be a real nuisance. They build mounds (nests or colonies) that sometimes stick up above the ground and ruin the grass in that area. When they are concentrated just below the surface, it tends to turn the grass Brown and it thins out and becomes patchy. This is just a part of nature. While Ants (and also grubs) traditionally prefer sandy soils, I have seen increasingly more and more in all soil types over the last 10 years.
How to treat ants in your lawn
- An application of Turfsolv helps considerably to keep the ants under control and prevents new ant mounts from forming for a few weeks (so be sure to re-apply once a month).
- You can purchase inexpensive ant powder, usually around £2 to £5. Here’s some on Amazon (affiliate link). Push a spade into the ant mound and wiggle it around to create an opening. Put some powder down into the hole while carefully avoiding getting it onto the lawn. Then close the opening and give the mound a squash down with your foot.
- You can use your hosepipe on a strong jet and literally blast the ant mound heavily to disperse the soil (and eggs contained within). Hint: Stand well back!
- You can wait for a dry day and use a brush to do the same. Literally, brush the soil all around to flatten it and disperse the mound. This works best if the soil is very sandy.
Dog urine
Dog urine contains a high concentration of Urea (aka Nitrogen, aka what is commonly used in fertilizer). This is very bad for grass and leads to your lawn suffering from scorch marks (just like if you spill fertilizer on the lawn). You will know immediately if the brown spots are caused by dog urine as they are very recognisable. The outer ring will be a darker green, while the centre is brown.
There are many products available to fix dog urine damage to your lawn. It is a common myth that female dogs tend to do more damage with their urine. The issue is not so much the sex of the dog, but more in the way that they wee. Females tend to crouch down and do a wee close to the ground, concentrating their wee. Male dogs tend to wee standing higher or cocking their leg up. Dog size also plays a part. Smaller dogs will naturally wee closer to the ground.
How to fix dog urine burns (and prevent new ones)
- There’s no real lasting perfect fix to this. You can “try” tomato juice or ketchup in the dinner bowl. This can sometimes work but not always.
- You can “try” dog rocks (affiliate link) that are placed in the dog’s water bowl (or soak water in a jug with the stones in for an hour before moving it to the dog’s water bowl. Again these work for some dogs but not all.
- Other things you can try are to saturate the lawn each morning with water (as a dog’s first wee of the day tends to be stronger if they’ve held it in all night). This helps dilute things.
- Try also watering each time you see the dog wee to dilute it, although this can be very challenging.
- You can also try to train your dog to wee in one spot. This involves putting your dog on its lead and walking to a set spot each morning. If you have to wait an hour or more then wait it out until your dog urinates in the new spot. Keep repeating this each morning. Eventually, the dog will associate this as its new place to wee.
- Finally, you could consider sectioning off the lawn (or most of the lawn) so the dog cannot go on it.
Weeds
If you have a lot of weeds in your garden, they can become a component part of your lawn. Many weeds are annual plants, such as Black medic or Cleavers (Galium Aparine). These will live and die in a cycle, meaning that they will not be present on your lawn the whole year around.
When these weeds die, they can leave a thinning, or if very large weeds, empty patches on your lawn. To counteract this you will need to stay on top of your weeding schedule. By not allowing your lawn to become inundated with weeds, you will not have to worry about them dying.
Also, when you apply a weedkiller, most weeds won’t leave huge gaping holes in the lawn once they’ve died, but some of the larger ones that have become well-established will. So applying a weedkiller once or twice a year will help control the numbers significantly. Be sure when choosing a lawn weedkiller that the label says “for lawns”. You will see several weedkillers that look perfectly fine but they contain Glyphosate in the ingredients. Glyphosate kills “everything” including lawns.
My recommended lawn weedkiller is Weedol (affiliate link).
If there are any patches once the weeds have been removed or killed, we advise using a patch repair treatment such as Patch Magic (affiliate link) to restore grass to the affected areas. Just be sure to prep the areas well by raking so you can see bare soil, to provide a good key for the seed to germinate in.
Debris and foot traffic
We all know how footpaths become etched into fields after people walk across them. The same is true in your back garden. If there is a path that people often follow to walk across it, over time this will wear down and cause the grass to grow less.
If you have anything left on top of the grass for a day or longer, this can impact your grass growth. The object will block the sunlight from reaching the grass underneath, eventually resulting in a brown patch.
How to fix your lawn thats worn down from debris and foot traffic
- So the first obvious answer is to avoid walking the same route each time (or install a pathway or stepping stones).
- The second answer is to avoid leaving things on the lawn for more than a day. This includes furniture tables and so on. Even the humble trampoline will cause the lawn to thin and eventually die underneath.
- You will need to mow the area short, then heavily rake the area so the soil is exposed. Then fork (or aerate) the lawn. Then scatter seed on top. Then grab a handful of topsoil, or multipurpose compost between both hands and rub it over the area till the seeds are covered with a layer around 10mm thick. Firm it all down and keep it damp for 4 weeks with light gentle watering often.
Thatch
This is commonly used as a term for old roofs but has meaning for grass too. In this instance, thatch refers to a build-up of decaying and dead plant matter.
This is found nestled in between the roots (sub-surface thatch) and grass blades (surface thatch) and prevents water and nutrients from reaching the root system. This means that the grass cannot uptake enough nutrients to support its growth, and will eventually begin to weaken. A weak lawn will encourage moss to creep in as well as weeds, further weakening the lawn. Eventually, the weeds and moss will take over.
If the thatch is left to accumulate then plants can even begin to grow root systems through the thatch layer. This does not contain nutrients or water, and eventually, the grass here will dry out and die.
To fix this issue, you will need to dethatch your lawn using a scarifier. It is wise to leave approximately half to a third of an inch of thatch on your garden. This helps to insulate the soil against temperature extremes, gives some cushioning, and helps to retain moisture within the soil without being too excessive.
Spills
If you use a petrol lawnmower to stay on top of the grass length, you will be familiar with the annoyance of refuelling. While it seems inconvenient to move the mower off of the grass to refill the fuel tank, we strongly recommend this.
That is because spilt oil and petrol can have a toxic impact upon the grass and can lead to dead patches on your lawn.
Regular brown stripes
These will often appear after you have fed the lawn, used moss control products, or weedkillers. This indicates that you have applied too much of the product to the lawn and you are now experiencing the negative effects.` I see this often when people have used “3-in-1” or “4-in-1” products a bit too liberally!
To fix this, you will need to ensure your equipment is carefully calibrated. This ensures that the correct amount of product is dispensed onto the grass and will give you the optimal conditions for even growth. When applying don’t overdo it (you can always re-treat it after 4 weeks if it’s not working as it should be, but you can’t remove any excess once it’s been applied!)
It is a good idea to apply fertilizer just before it is due to rain or watering the lawn well after you fertilize the ground. Alternatively, you could opt for a controlled release lawn fertilizer.
