Question
We live in Southern California. Up until about three weeks ago we had a beautiful St. Augustine lawn. Yes it's been hot here. About 100* recently. I increased the watering from once a week to two times a week, sometimes three.
I water the lawn for about 30 minutes a section.
Twice a year we feed it with stuff made especially for St. Aug needs.
It began to die, like I said, three weeks ago.  Big pale brown patches almost overnight. It's as if my lawn is turning to straw.  There are a few green patches left, but they have dead grass in them too. I would say that about 40% of the lawn is brown.
The lawn next door is green as can be. Their yard is connected to ours and is also St. Aug.
Up and down our street, some of the lawns are dying like ours and some are green and beautiful. The guy next door waters at the same rate as we do.  Please advise if you can.

Answer
Hi Donna;
The watering program you are on could be the culprit.
If you are watering in the evening, so the grass is staying damp through the night, you may be causing a fungus called brown patch.
It starts in sort of circles and spreads outward. You will usually get more than one circle.
Watering for 30 minutes may or may not be sufficient.
How DEEP you water, is more important than how often.
Shallow watering causes the roots to come closer to the surface to get water. that exposes them to excessive heat damage. It also promotes a thatch buildup.
I have st. augustine too, and that typr of grass loves water.
I water to a depth of at least 6 inches, to encourage the roots to go deep.
I try to water early in the morning, so the water soaks deeper and less dries out from the temps.
I usually water only once a week, and if it gets to 100 a couple of days, my st. augustine stays green and nice, because it's feet are down there where there is still some moisture.
St. Augustine tells you when it is thirsty. It folds it's blades in half, to expose less surface to the heat, to slow the drying out. Makes it look more like little sticks than grass.
I use soaker hoses so all the water I have to pay so much for, goes into the ground, and none is lost to evaporation.
when you use sprinklers, and the temp gets past about 95, you can lose 50% or more to evaporation. So if sprinklers are how you ae watering, you could be only getting half or less of the water into your lawn.
I am on an organic program, so I use baking soda disolved in water for a fungicide.
It works for me better than Funginex, which was what i used when I used chemicals.
Going on organics has just solved all the lawn and garden problems I had for so many, many years.
I have a healthy enviornment for beneficial insects, and nemetodes, lawn critters ( toads, lizards, etc), and they eat all the harmful insets, including the aphids that used to eat my roses. they do a better job of keeping rid of all these things that spraying with insecticides on my plants, and spreading insecticides on the grass once a month, did before.
They work cheap and they don't bring on asthma attacks.
To use baking soda for fungus, mold etc, I disolve 1/4th cup per gallon of water, and spray until vegetation and soil is saturated.
I don't know what you are treating that is for St.Augustine, but since I went to an organic program, my St. Augustine is thinker, greener, healthier, and weedfree.
Organics is more about what yopu DON'T do rather than what you do.
All I have put on my grass for the last 8 years is sugar each spring and fall, and water it in.
Fertilizers kill the beneficial microbes that enrich the soil.
They work round the clock, and they will eventually enrich the soil so it needs nothing else to maintain a healthy lawn and garden. there are some organic products that can increase the benefits faster, but they are optional, and you don't have to use them to get great results.
I have started to learn more about these products this last spring, and am trying some of them. I have not been using them long enough to see the results to the point I am ready to recommend them.
I will share the information with anyone who wants it, if they want to try them on their own.
For now, I would say your best bet would be to treat for fungus, and water deeply to get more down deep, so you won't have to water so often.
Water until it is wet 5 to 6 inches down, at least, then treat for fungus.Wait a couple of days, at least before putting any more water on the grass.
Dig in a little and see if the top two inches are dry. If it is not bone dry down there, waut another day to water.
Watering with a soaker hose, or just laying the hose down and letting it flood an area, them move it to flood another area, will take more time and attention, but it will keep more moisture off the blades, and give the fungus a better chance to die.
After that good a soaking, you should see a little greening in the healthy areas in just a day or two.
When they spots stop spreading, the fungus is dead.
If it is not a fungus, it should start to green up there in a couple of days too.
If there is any healthy root left in the infected spots, the grass will come back ithout resodding.
If you would like to read more of my answers, to others, there is a lot of organic information in there.
If you still have questions, feel free to write me anytime.
I love sharing what I have learned.
Charlotte
I use herbs inside the house, and I have no indoor insects to deal with.