Alkaline in the soil my white fanny. Not the white soil marks. :-)

Grasses grow just fine up to a pH of about 8.5, which you don't have.

What it looks like you have from a casual look is a rampant fungus, caused by severe overwatering. Seriously, dude. Four times per day?

Cut that back to once every other day immediately. I don't care if it's 115, established grasses don't require that much water and might, at worst, need what's called a syringing at 1:30 PM...about 1 minute of water just to damp the surface and cool things off a bit. Pro tip: grasses that are covered in white fungi don't need anything except a funeral.

I'm guessing California, Los Angeles area? Let us know your exact location for a better watering schedule, but...at this point, stop watering the graveyard anyway. Cut it back and let anything that survived (not much, I'm thinking) spread.

Thank you for the help. when you say to water once every other day, how long do I water for and what time of day would you recommend?

The normal time is early in the morning and I don't see a reason to change that here. So whenever convenient that doesn't interfere with your normal shower and water usage times and whenever your local authorities allow, if they have any restrictions.

Normal amounts are to target an inch per week. There are reasons to change that here but...initially, let's target that. If you know what your system puts down per hour, figure out how long to water to target one inch of water on the lawn per week and then observe. At those temperatures, you may notice the remaining green grasses require a little to considerably more. If so, increase it. That will depend on the temperature, winds, grass types, and so on.

If you don't know, set the system to run for a reasonable period of time (if it currently runs for an hour, say, leave it there). Put empty tuna cans out on the lawn to catch the water (or just one, moving it around) to see how much water goes down and measure the amount in the can. That'll give you a guide as to how much your system puts down in each area, then set the times accordingly.

That every other day is only temporary; in about three weeks as the lawn begins to recover and the existing grasses regrow roots, see if your remaining lawn can tolerate every third day. Maybe it can. Maybe it can't. I don't have much experience with temperatures that high and don't know what soil type you have.

At that point, it's also time to think of a wide-spectrum fungicide to clear the field for re-seeding, although I'm going to see if David comes along and sees this. He's more familiar with desert grasses and reseeding in those locales than I am and will give far better advice.

On the other side of the fence (pardon the pun), if your system was only running for a very short amount of time, putting down only a few tenths of an inch per week, and the photo was slightly fuzzy, I could be miscalling the whole thing and this could be burned-out grasses from underwatering. :-) But I don't think so. In either case, it's smart to know how much water your system is putting out and to water as rarely as possible and as little as possible anyway. The grasses prefer that and it's easier on your wallet.

I'm in s.cali,Oceanside along the coast and i water twice a week for 30 minutes,and that seems to be enough to keep it green.Of course just being in Cali just means that i can't water as often as i used to so the grass is not as pretty,but is still green.That's the price of living here.

A couple years ago we had to tear out the backyard grass and replace it with rock because of the water shortage and not being able to keep it up.I still wish we could have grass back there,but i do what i can,to help with the water situation here.

Thanks for the advise again. First going to measure the amount of water it is getting daily then report back. also, the grass in picture is Saint Augustine. Not sure of that matters.

St. Aug's about average in terms of water requirements, so that's...well, not great in any area that's stinking hot with lower level rainfall, actually. One might consider a more drought-tolerant (once established) grass like buffalo or the like.

But again, I'm really not the person to make desert recommendations.

St. Augustine is fairly low water use. You are probably overwatering, but the white stuff can also be from salts in the soil. My neighborhood was built on the site of an old dairy, and we get a white crust when it rains. Try gypsum, which is a treatment for sodic soil. This information may help: Guide to Healthy Lawns (UC)

Well, I put out cans and seen that I have very inconsistent watering patterns. In the middle areas in my lawn I got a few droplets in the can which is where all the white haze is. I dug down and it was pretty dry. the outer areas and orange looking grass were very damp and the green areas are extremely wet. So might have multiple issues. looks like step one is letting everything dry out for the week, fixing sprinklers and go from there.

So change of plans. First, nail down issues with the irrigation system and fix 'em. Once that's consistent across the board, we go from there.

With slight irrigation in the center, simple death from drying out and just turning white from desiccation becomes a lot more likely. :-) The ultimate target, at least to start, is about an inch a week across the whole lawn...but that will need to adjust for your pretty harsh climate, of course.

Yeah,you were not overwatering in that heat. In fact,underwatering and that killed the grass. The mold is growing on the dead grass.

I say it here all the time,almost nothing dies from overwatering in California..its almost certain the opposite.

Where the water pooled and sank in? You have picture perfect deep green lawn. You might try renting a lawn plugger...it will pull out little tootsie roll thingys...and water will sink in to the root zone like you want.not slide off the surface.