Since your neighbors all have bermuda, you're going to have to ignore their maintenance practices. Bermuda is about the opposite of other grasses. It needs fertilizer every month and very low mowing twice a week. You can just sit back and watch them work.

You sound like a relative newby to St Augustine and possibly to lawns altogether. Here's what you need to know about watering. The watering mantra is deep and infrequent. Again, this might run contrary to your neighbors even though it should not. Deep means 1 inch all at one time. Don't spread it out over the week. Time how long it takes your watering system to apply an inch by setting several cat food or tuna cans around the yard and timing how long it takes to fill them with water. My oscillator sprinkler with my hoses and water pressure takes 8 hours to fill them. My neighbor's high flow system takes 20 minutes. You'll likely be in between those extremes. Once you know how long it takes to fill the cans, that's your watering time from now on until something changes. Infrequently means you let the soil dry out completely before you water again. There are many factors but the one factor that seems to dominate is air temperature. When temps are below 70, water about once a month unless it rains an inch. With temps in the 70s water once every 3 weeks. Temps in the 80s water once every 2 weeks. Temps in the 90s water once every week. Temps above 100 water once every 5 days. If you have prolonged temps above 110 water every 4 days. THIS WORKS! It works in Phoenix and it works in Vermont. Simply fixing your watering schedule can resolve lots of lawn issues. It likely will allow your grass to remain green longer in the fall before dormancy. So ignore what your neighbors do with their watering frequency.

One more thing about St Augustine. When the air temps are in the 70s it will spread over the surface of the ground. It can grow an inch or two per day as long as the weather is mild. You'll notice it most around the borders of the lawn.

One other thing about St Augustine is that it is prone to fungal disease if you cut off the air flow around it. If you have kids, don't let them leave big toys out laying on the grass. My wife likes to prune the garden and toss the clippings on the lawn. Well, I've finally raised her awareness to this, but before that it would get disease every year. Corn meal, as you have already mentioned, is the solution to this.

And another thing in general, if you listen to Howard Garrett on the radio and have questions about anything he says, please ask for a second opinion here. I am the (seldom seen) moderator on his lawn forum, and I do not always agree with his recommendations. He's more of a salesman than I am. He's got a product for everything, but sometimes just good practices will fix the problem.