Since you're in Cumming Ga, I thought you might want to check out one of the better landscaping companies in the State, who just happens to be right down the road from you. I'm not affiliated, but just wanted to pass them on as they do excellent work. As for your soil, it is typical of GA soil in that it has a very low exchange capacity. This means that it won't hold nutrients very well, which can be offset by using slow-release fertilizers, or by improving the soil with the addition of compost. My soil supplier is on the south side of Atlanta, but I'm sure SEL could recommend someone local if you're doing the work yourself. Also, it's been a closely held belief for years that Centipede doesn't perform well in a pH above 6 (I shared this opinion for 15 years). Texas A&M shed some new light on this a few years back with a mass-cultivar study in which they grew every cultivar of Centipede at a pH of 8.0. The trick was that they supplemented with chelated iron, otherwise the grass would have lost all color. The study proved that the issue was that iron tends to be less exchangeable as the pH increases, this leads to chlorosis (iron loss), which Centipede is very sensitive to. However the root systems in the higher pH levels grew much deeper. The lessen there was that with a pH that's just slightly acidic, like yours, you can actually have a more drought tolerant stand, but you will need to supplement with iron during the growing season (part of a normal centipede program anyway). The ideal pH recommended by most extension agents (Texas A&M included) is still 5 to 6, but again that is based on iron uptake. Here is a link that might be useful: South Eastern Landscape Contractors

You picked a doozy of a topic to reference. I don't think I've ever seen so many people piggybacking onto one thread. The spots you see on your grass are the same as those I posted in that other topic. The corn meal should help. Give it 3 full weeks. This is not a shade issue or a watering issue. St Aug will be thinner in the shade but it should be healthy looking with zero spots or yellow blades. Here's a picture of my lawn in San Antonio growing in deeper shade than you had. The point of this picture is 1) no spots, and 2) lots of shade. I took this picture to illustrate chlorosis in St Augustine caused by too much rain. The yellow blades in the center are from the rain. The point you cannot see is that this area looked horrible a month earlier from disease. You could see the soil, leaves, stolons, and spots on the few living blades of grass. Note that you can still see through the turf a little to the stolons underneath. If this was in full sun it would be so packed in the blades would be growing straight up. I'll get a picture of my new lawn in Bandera looking straight down. It's very hard to push a mower through that stuff. Okay I have to comment on the TAMU pamphlet on growing St Augustine. Generally when I see something from TAMU I read it and do the opposite. Truth! Here's my experience this year. I live in Bandera now, so think Texas Hill Country. Our temps ran in the mid to high 90s this year. We got our first rain on Memorial Day and it nearly washed my belongings out of the garage. It was 11 inches in 3 days with most coming the first night. That's too much rain so I was expecting to get some disease. I did but only about 1 square foot was affected. But since Memorial Day I have watering the actual grass one time. Fortunately we got some rain relief last week, so from June 1 to Aug 19 I did not water. Had I followed TAMU I would have watered it every 5 days. Had I followed my own advice (below) I would have watered it every 7 days. What the TAMU people did was over simplify watering, but then they went into too much detail on how to achieve the simple watering. Watering is slightly harder than they suggest but setting it up is easier than they suggest. Here's my take on watering after reading and moderating lawn forums for 10 years. 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. I guess I should add that if it rains 11 inches, reset your calendar back by a month at least. Mowing height. If you read the topic you referenced you saw pix of my dog in the tall grass. (We found her and she's up at the new house in Bandera). From those pictures you can see that tall St Aug is pretty healthy. I seriously did not water, mow, fertilize, or weed that lawn from October 2011 through Feb of 2015. All it got was rainfall. 2011 and 2013 were drought years, and it thrived. Point is keep your st Aug as tall as you can stand it. Set the mower to the highest setting and weld it in place. Contrary to what TAMU says, mowing it low does not make a better turf. Fertilizing. If I was on a rigorous fertilizer schedule I would use organics 5x per year following the federal holiday schedule (Washington's birthday, Memorial Day, 4th of July, Labor Day, and Thanksgiving). If I was on a casual schedule I would fertilize on Memorial Day, Labor Day, and Thanksgiving. If you decide not to use organic fertilizer, I would still strongly suggest you use it at least once a year in addition to, or in lieu of, one of your fertilizer apps. The general experience of the universe of lawn care websites is that lawns that get no organics for 10 years or so will develop issues where the chemical fertilizer seems to not be effective. One dose of organics will reset the soil biology and the chemical fertilizers will work again. I think you can avoid that issue by preempting it. Organic fertilizer is much less expensive per 1,000 square feet than compost. The fertilizer is also much easier to apply than compost.

More important than the fuzz are the brown lesions on the grass blades in pictures 2 and 3. Mushrooms mean you have far too much water. At this point it is too late to adjust the water and get rid of the disease. If you have the Floratam variety of St Aug, it will fight back but will take a long time to fully recover. I have had success with this type of fungus by using ordinary corn meal applied at a rate of 20 pounds per 1,000 square feet. You can buy corn meal at feed stores in 50 pound sacks for under $10. Call first to be sure they have it. Corn meal works biologically rather than chemically. Corn is decomposed by various fungi. One of the fungi that comes in with the decomposition is a predatory fungus. It feeds on other fungi including the one that causes the disease you are seeing. Apply the corn meal now and in 3 weeks you should see the browning stop and no more lesions. If you cannot find corn meal at a feed store then buy corn flour at a grocery store catering to Hispanic shoppers. Cost should be $7 for a 25-pound bag. Be sure you don't get the stuff with baking powder in it. That's like the Bisquick for making tortillas. You want the plain corn flour, masa de maiz. Maseca is a popular brand. You should back way off on watering frequency. I would give it a week to dry out watching for wilting. In fact I might go until it starts to wilt somewhere just to make sure it is dry enough to water. Then start with deep watering. Start with 1/2 inch of water, twice a week. If it rains, don't water for a week or possibly longer depending on how many inches of rain you got. When this is mature it should easily go a week in the summer heat without watering.

New sod care details