Yes. It's St. Augustine. In Houston, all good-looking lawns have St.
Augustine. Bermuda is often treated as weeds down here. But I have St.
Augustine with some Bermuda mixed in my lawns. :)
The grass in the centers of those brown patches seem dead. It's caused by
lack of water and the horrible heat of the sun. There's not much you can do
about it right now on the dead grass. It's way too hot these days to replace
. The good news is that you really don't need to worry too much and the
grass will grow out next year. This has happened to me a few times in the
past.
What you need to do now is to prevent the brown patches from getting bigger.
I agree with what ezf said in general. But I don't usually water each zone
for that long. I would water each zone for 20min every 2 days. Each zone is
different, you need to make a test run to make some adjustments. When you
make a test run on each zone, you can check the springler heads, make sure
no one is stuck under the grass, and the water is sprayed out evenly in the
"good" direction. Sometimes you have to adjust the heads a bit if the spray
direction isn't quite right. Not every srinkler system is perfect. Quite
often, there are a few spots that no sprinkler head can reach when it sprays
the water out. I suspect your problem is caused by this, or those zones
didn't get watered long enough. In the long run, you can install a few
sprinkler heads yourself in winter. For now, you need to drag the hose to
water those missed and dry spots.
Anyway, this is just my experience. I'm no expert in lawn care.
Hope this helps!
