The problem is root rot, but I'm confused about the time line. What order did all this happen? Because last Saturday, the day you said this happened, there was a hurricane going through Houston. Did you get 50 inches of rain and then water it again? Or did this happen Saturday a week and a half ago? And as of today, is this still your greatest lawn priority? Does it still look like this or is it covered with hurricane debris?

What was your watering schedule prior to the rain? How often and for how long did you water?

Did the lawn turn yellow before the rain?

I assume this is St Augustine, right?

I have to assume this was Saturday the 19th. Fertilizing and watering was the wrong thing to do. Don't water it again for at least 2 weeks to let it dry out from the rain. You may not need to water it again for the rest of the year. Does any of the grass seem to be surviving? If the hurricane did not spread this throughout, then you need to nurture the surviving grass...but not by watering it. Once we know more about your prior watering we should be able to determine how it happened to prevent it in the future.

The problem is root rot, but I'm confused about the time line. What order did all this happen? Because last Saturday, the day you said this happened, there was a hurricane going through Houston. Did you get 50 inches of rain and then water it again? Or did this happen Saturday a week and a half ago? And as of today, is this still your greatest lawn priority? Does it still look like this or is it covered with hurricane debris?

Yes this was noticed around the 19th a week prior to the hurricane. I live near Lake Houston and we did not have any high flooding or debris, the discoloration is the lawn itself. We received the rain during the hurricane.

What was your watering schedule prior to the rain? How often and for how long did you water?

I was watering about twice a week about 7 minutes each zone, and there are 8 zones.

Did the lawn turn yellow before the rain?

Yes it was yellowing the week before the storm him to I upped my watering to 15 minutes, still twice a week thinking it was dry because we had no rain for a few weeks.

I assume this is St Augustine, right?

This is St. Augustine

I have to assume this was Saturday the 19th. Fertilizing and watering was the wrong thing to do. Don't water it again for at least 2 weeks to let it dry out from the rain. You may not need to water it again for the rest of the year. Does any of the grass seem to be surviving? If the hurricane did not spread this throughout, then you need to nurture the surviving grass...but not by watering it. Once we know more about your prior watering we should be able to determine how it happened to prevent it in the future.

After the hurricane there is a patch that does seem to sprout out. The front yard has 4 patches of it but there is some surviving green. I did purchase 5 bales of peat moss but have not spread it due to the fact that hurricane would have washed it all away.

Sorry for the delay getting back. I have a vacation condo in Rockport so we have been dealing with hurricane debris and salvage.

The initial problem was improper watering. When roots get a fungus and rot away, the plant above dries out making it look like it is not getting enough water. Truth is the plant is not getting enough water, but the cause was too much water. Watering dead roots doesn't fix it.

At this point you have to hope some of the roots were not completely dead and will return once things dry out. Adding fertilizer stressed the situation rather than fixing the situation. Of course watering after the fertilizer was necessary to dilute the fertilizer, but the yard already had too much water. What I would do is to buy a bag of ordinary corn meal at your local feed store (call around for availability). Scatter that at 20 pounds per 1,000 square feet. And don't water it in. If the soil has already dried out and the corn meal does not start to look gray in a couple of days (a good sigh of decomposition), then lightly spray over it with a hand held spray nozzle. All you need to do is moisten the corn meal. Corn meal will help feed the soil microbes and, hopefully, kill the disease microbes causing the roots to rot. If you don't see any green up after 3 weeks, then the lawn is likely dead. I would not water it again for at least a month to be sure the soil is drying out.

Here is some information about deep and infrequent watering.

Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.

That is what you should have been doing instead of watering every other day. In Houston while the climate is unbearable in the summer, the problem is humidity and not the actual heat. Humidity keeps the water from evaporating, so rather than watering once a week, you might be able to water deeply once every 10-14 days in the summer.