Help - I think DH has killed our new lawn

[SaveMyGrass]

We had our garden returfed just before lockdown so at the beginning of March.

10 days ago DH decided to treat it, I wasn't aware of this. He applied Evergreen 4 in 1.

Almost overnight the lawn developed dead brown patches and I couldn't understand what had happened, he then told me he had used this treatment.

I have looked at it and it says that it shouldn't be used on lawns less than 6 months old. It also says you would see an improvement in 7 days. It has been 10 days and there are just brown empty patches.

I am worried about the rest of the lawn too now as it isn't looking to great in more places.

The treatment says you can't reseed for 8 weeks afterwards.

Is there anything we can do to salvage this? Please help I am ready to kill him, I used my bonus to pay for new grass and am absolutely gutted.

I'm not a grass expert. But it sounds like it's been burnt by the fertilizer in the treatment. I would water it lots for a few days to try and wash off the treatment.
Then reseed the burnt bits

How big are the brown patches? Is the grass around them looking ok?
Was there any particular reason he thought the lawn needed treatment - eg had it developed moss already?

A photo or two (closeup and larger view) might help work out what to do.

Lawns are pretty tough, but the treatment might have scorched patches. I think you will have to just watch and wait. Make sure the grass is well watered, even if there’s been rain showers some of it might still be dry.
Years ago Monty Don patched his lawn by sowing grass seed in shallow pots/ trays and then when it was mature enough planted it in the bald bits. You could sow some seed this way and then after 8 weeks you’d have some grass to fill in the patches.

Dh is a bit of a lawn lover and did similar to ours recently. He said it was the weeds being killed and leaving the patches and a month ish later it's all green and lush again

Thanks everyone, I have some photos.

He said it had moss developing.

It's hard to tell from the photo - is the dead stuff mainly moss or grass?
Our lawn looks pretty awful after a moss treatment but it would be worse in the long run if it was left.
I'd be inclined to get him to carefully rake out the dead stuff (without raking up the grass around it) , water well and hopefully the grass will grow back - it's tough stuff.

The dead stuff looks like it is mainly grass to be honest. Thank you will give that a go. I am not sure what possessed him to do this now, it looks so awful looking at it out of the kitchen.

I manage to burn mine last year with weed & feed because I didn’t water it enough after applying and it burnt the grass-old established lawn btw.

It looked awful since last August but this year the grass has grown over and spread to fill in the bald bits and it’s looking lovely.

Our neighbours did this. Moved in and practically straight away decided to treat the newly turfed front lawn. It all went brown, literally all of it. Looked awful. They left it and this year it's grown back and looks fine. So it might depend what you're able to live with in the short term? If you make sure it's adequately watered (which is less than ideal this year as we're heading for a water short gage - get a water butt!) it may well grow back

Grass is very invasive op. It will regrow, just not quickly, you’re not going to wake tomorrow and it’s grassed over. It may even be , and maybe likely to be, as long as next year before it’s taken.

It will however re grow. Personally I’d wait the eight weeks then put new seed down. Four in one contains a pre emergant which prevents seeds germinating hence why you can’t reseed for eight weeks.

Thank you all for reassuring me. Just so cross that he didn't read the instructions properly, I want to cry every time I look at it, as it was so beautiful and the garden look so lovely and now it just looks like a barren dessert, I don't know what possessed him. Lets hope it doesn't take a full year.