You are watering too often. Cut back. Water only if NEEDED. My rule of thumb is to water when your lawn starts to wilt. Water about one inch of water. Put out tuna cans and find out how long it takes to fill it up. It could be every week or two weeks. If it rains a lot, expect to go quite a while before needing to use sprinkler system if it hadn't rained for a while.

How high do you mow? It looks a bit shortish. I mow mine at 4 inches during summer to conserve water and it helps a lot.

Hey Daniel.

Your landscaper might have been talking about a watering plan to get the sod established. Once it is established, you can cut waaaaaaay back on watering. I have been watering once a week starting a month ago. Before that I was watering every other week. If you are watering daily, you will have to wean the roots off the water. Start by not watering tomorrow but water for twice as long the next day. Then leave it alone for two days but look carefully for signs of dryness. Water on the third day for that same "twice as long" time. The idea is to get water deeper into the soil and then let the grass roots go looking for it. They will. And the reason for not watering daily is that grass and weed seeds need daily moisture to germinate. When you deprive the weed seeds of that necessary moisture, they cannot germinate.

Regarding your organic fertilizer, you cannot hurt the lawn by using double or triple the recommended rate. You might hurt it at quadruple but then it would be because you smothered the grass. I have written an Organic Lawn Care FAQ if you are interested in reading more about it.

I agree with Lou that it looks to short, too. In fact I'm not sure the browning problem is not related to scalping. I would raise the mower one notch every week until you reach the highest setting. Then WELD the mower adjuster in place so some well meaning friend or relative does not borrow it and readjust it for you. There is never any reason to mow St Augustine at anything but the mower's highest setting. Tall St Aug resists weeds and chokes out most grassy weeds. It also takes less water because the soil is shaded and has less evaporation. And tall grass grows deeper roots.

Okay I just thought of something else. Your brown spots might be a disease exacerbated by the rain. You can use some fertilizer anyway so I'm going to suggest that this time you use ordinary corn meal (NOT corn GLUTEN meal). Use it at 20 pounds per 1,000 square feet and cover the entire lawn. You can find ordinary corn meal at a feed store and possibly at John Dromgoole's nursery. Call first to be sure they have some. If they do not, ask them who might. I'm not that far south of you and I can get it everywhere. Corn meal works biologically to kill fungal disease. You don't have to diagnose the disease first, just use the corn meal. The lawn should be looking great (at 3-4 inches high) in 3 weeks.