Dead patches in new grass this year… What went wrong?

There’s a lot of confusion around dethatching these days, and a lot of it comes from non-experts like YouTube creators. People mix up thatch with grass clippings, but they’re different. Thatch is made up of dead and living grass stems and roots. The real problem starts when thatch gets too thick, more than an inch, which can create bigger issues.

If you’re dealing with excessive thatch, things like overwatering, fertilizing too much, or even using certain insecticides could be to blame. Some methods, like using a tine dethatcher, can do more harm than good, but alternatives like core aeration can help break down thatch without destroying your grass. You might also want to look into slit seeding or scarifying instead.

Don’t get rid of the thatch unless it’s a major issue. Some thatch is actually good for protecting your lawn. If the thatch layer is thin, it helps with preventing weeds and even holds onto moisture better. But if it’s too much, dig in and figure out what’s causing it.

Did you remember to water it regularly?

Paxton said:
Did you remember to water it regularly?

Yes, I watered it often during the first month. I live in the UK, so rain is frequent.

Zade said:

Paxton said:
Did you remember to water it regularly?

Yes, I watered it often during the first month. I live in the UK, so rain is frequent.

I’m in southeast England too. Did you keep up with watering during the summer?

@Paxton
Yes, we did water it in the summer. But we went away for about a week a month ago, so it probably missed a few days then.

Zade said:
@Paxton
Yes, we did water it in the summer. But we went away for about a week a month ago, so it probably missed a few days then.

It looks like what happens to my lawn when I skip watering in the summer. Maybe you didn’t give it enough water? New grass has shallow roots and needs more care than older patches. If it’s rained a lot recently, the ground is likely well watered now, but keep an eye on it. If it doesn’t improve, you might need to rake, scarify, and overseed.

I had a similar issue with my lawn and realized I was underwatering. After a heavy rain a couple of weeks back, my lawn turned completely green again. Deep watering is key, not just frequent light watering.

Zade said:

Paxton said:
Did you remember to water it regularly?

Yes, I watered it often during the first month. I live in the UK, so rain is frequent.

It could be grubs. Try scarifying or using a leaf rake to remove them.

I wouldn’t stress about seeding or aerating too much. One of the grass types you have probably spreads on its own. That’s good and bad—it’ll fill in bare spots, but it’s hard to get rid of. If the grass gets water and fertilizer, it should bounce back on its own over time. Fertilize every six weeks and water a few times a week. It should take care of itself.

@Harper
Thanks! Just to let you know, the area was completely bare before we planted the new grass, only flowers and soil were there before. Do you have any specific fertilizer you recommend? Luckily, there’s a lot of rain expected this week.

@Zade
Nothing fancy needed! Just grab a basic fertilizer from your local store. Something like 25-0-5 would work fine, but don’t stress too much about the exact numbers.

It might just be that the summer was too tough on the new grass. Was the soil aerated properly? And does the area get full sunlight all day?

If you suspect grubs, try putting a tarp over the lawn after watering on a sunny day. That should help take care of them.

Willow said:
If you suspect grubs, try putting a tarp over the lawn after watering on a sunny day. That should help take care of them.

And don’t forget to clean up the clippings afterward.

What type of grass seed did you use? I made the mistake of buying a mix that was mostly annual ryegrass, which dies off in the heat of the summer. I’m in southeast England too, and my lawn looked a lot like yours until I reseeded it.

It could have gotten too much water.

You should remove the dead grass because if the soil stays wet and you keep watering, you might end up with brown spot. Also, if the grass is pulling up easily, it could be part of the problem.

I was thinking it could be fungal disease causing the dead patches. Have you noticed any discolored or moldy spots on the grass? Sometimes the moisture can encourage that kind of problem. You might want to check if the grass pulls up easily, as that could also be a sign of grubs or a fungus issue.

@Ocean
Good point. It could be a fungal problem like brown patch or dollar spot, especially if the weather has been humid. Checking the roots might help confirm it.

It could also be that the soil is compacted. Have you tried aerating the area recently? Compacted soil can stop water and nutrients from reaching the roots, and that could be why your grass is struggling.