@klargo I'm by no means an expert but it looks like in some of the areas that got scorched a second grass has moved in. Possibly Bermuda. Do you notice a different looking grass in those areas?

 

It's all St. Augustine for sure. Some of it just looks...sick. The blades are much smaller than the healthy grass, and the growth is stunted. In the 3 weeks since this lawn was mowed, the healthy grass is 5-6 inches long while the sick stuff has barely grown at all.

 

Have you checked for insects/worms/grubs? If it's Take All you'll have some root rot.
I have some slow to fill in areas like yours in my lawn where there was standing water that drowned the grass and some where I under irrigated and fried some spots and also some that were thinned out by Brown Patch.

Currently throwing some quick release fertilizer down in a section of the slow area as a test to see if that kick starts it.
Also considering some Humic 12 and Air 8 to see if that helps but will wait on the quick release test results first.

But I'm not worried too much at this point because when I moved back into the house last July the grass was growing well as were the weeds which I've since taken care of.

 

Tough to make a diagnosis based on pics. If I were you I would put down some quick release fertilizer and caravan g to cover all bases

 

Irrigate a few times a week and maybe hand water the scorched looking area

 

Take some closer pictures so we can see the grass blades. From that distance it doesn't even look like St Augustine to me. Anywho, I had problems all year last year with fungus. Get a good preventative program going g with fungicide if you want to keep healthy turf year around.

 

You said you turned the irrigation off have you turned it back on?

 

I'm 75mi south of you and have very similar problems. Beautiful and thick in some areas but tiny, sometimes sick looking grass in others that doesn't grow much at all (see my "dwarf St. Aug? post https://thelawnforum.com/viewtopic.php?t=8339). I put down some fast N today before the rain and hope that helps.

 

I did turn the irrigation back on last year and it's been on ever since. We are allowed to water with an irrigation system twice per week here. And then I've done some supplementary watering once per week on the ugly spots. It's not helped.

I don't see insects - I'll check for grubs. I did go out and pull some of the stolons from the weak areas and the roots are short and dark. Also there's some chlorosis in the weak spots.

Thanks for the replies, more pictures attached:

Healthy spot:


Weak spots:

 

I wouldn't worry the healthy grass looks good. I bet with some fert it will be super thick by the end of June. Have you put any fert down? Get a close up pic of the yellow blades.

 

I wouldn't worry the healthy grass looks good. I bet with some fert it will be super thick by the end of June. Have you put any fert down? Get a close up pic of the yellow blades.

I hope so! I put down a good dose of Milorganite back in March. That's all so far besides the fungicides this past weekend. Here's a closeup of the yellowing.

 

Around were I live we get a lot of iron chlorosis. I put down some liquid chelated iron and it will green it up.




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I didn't want to take any chances with the root rot potential, so I threw down peat moss on the worst affected areas. My concern is that the chlorosis is present where the grass is badly thinning. There's no chlorosis in thick grass so I'm not sure iron deficiency is the problem.

I'm hoping the worst case scenario is that nothing happens. Best case scenario I see improvement.

Either way I'll put down some fertilizer in 2 weeks or so and hope the summer brings happy grass.

 

... My concern is that the chlorosis is present where the grass is badly thinning. There's no chlorosis in thick grass so I'm not sure iron deficiency is the problem. ...

Please keep us updated, I've got the same problems. I already put down fert (probably a bad idea, I didn't know N helps fungus spread), sprayed a light dose of Eagle 20EW two days ago and spread some peat moss today (what a mess). About to get some rain to water in the moss.

 

Please keep us updated, I've got the same problems. I already put down fert (probably a bad idea, I didn't know N helps fungus spread), sprayed a light dose of Eagle 20EW two days ago and spread some peat moss today (what a mess). About to get some rain to water in the moss.

I've done pretty much the same exact thing. Last week I put down some Disease-Ex (azoxystrobin)for gray spot. And followed that up a day or two later with Eagle 20EW. Peat moss yesterday. I figured worst case is I top dressed weak spots.

And we just got poured on so pretty good timing on that.

I'll keep this updated. Good luck with yours!

 

I'm pleased with the results so far, but it's tough to attribute the success to any one action. I've put down peat moss, fungicides, fertilizer, and I filled a bunch of totally bare spots with plugs. It's not as thick as it looks in the pictures, but I'm now convinced I can get there.

 

Looks like a great recovery in the end...

 

Interested to see updates too. I recently laid st Aug sod and it's a little thin in areas. Anyone know if it'll thicken up? My issue may be more shade related.