Thanks so much for the helpful advice. Your feedback is very insightful. I do have a couple follow up questions:

1) you mentioned that my brown areas and dying new sod is not a shade issue or a watering issue. If it's neither of those then what is it? Is it because we got so much rain last week and I had been watering it the two weeks leading up to that?

2) I am noticing mold growing on the cornmeal in areas where it clumped up in the sod. Is this normal and what should I do with the mold?

3) What kind of organic fertilizer do you suggest I use? There are lots of choices.

4) What kind of spreader do you use for organic fertilizer and cornmeal? I have a scotts hand held electric spreader, but used a large cup to spread the cornmeal.

Any chance you could help me out with those couple of questions?

St Augustine is very sensitive to being covered up with anything. Before I trained my wife she used to drop yard clippings on the grass. If that stayed through even one dew cycle, there would be spots of disease forming on the grass underneath. My kids used to leave toys on the lawn and that would do it, too. So cutting off the air flow around the grass when the grass is dewy is enough to kickstart a disease. If you have Floratam St Aug in full sun, that stuff grows faster than the disease can spread and will not thin out, but if you have anything in the shade, the disease will take it out. Even tree leaves, even live oak tree leaves, if they stay on top of the grass will cause the disease. I end up raking the tree leaves into the wife's garden beds as a mulch.

The mold on the corn meal is the active ingredient. That's what you want to see. Of course next time just kick the clumps of corn meal to spread it out. The mold looks gray on yellow corn meal but it is really blue green. It's called trichoderma (try koh DER mah). The trichoderma is a predatory fungus that feeds on other fungi. First it feeds on the fungi that decompose the corn. Then when the population has built up on the corn, it attacks the disease fungi.

I don't use a spreader. Grain type fertilizers will clump up in the humidity here, so you have to keep bouncing the spreader. I broke mine after a season of bouncing it along. I have a 2-pound coffee can I use. I fill it and then eyeball out a 100 square foot area (10 feet x 10 feet). I apply 2 pounds inside that imaginary square and reload to the next spot.

I like to use alfalfa pellets (rabbit chow) because it is available everywhere and relatively low cost. I also use corn meal for the same reasons - at least in my part of Texas it's available at every feed store.

Good to know! thanks for the info. one last question. When you "reset" your watering frequency, would that include a light sprinkle? Example: Last Friday we got some rain. It then sprinkled a trace amount monday and tuesday of this week. Should I wait until monday or tuesday of next week eventhough it sprinkled a trace amount those days or should I just go ahead and do a deep watering this Friday since it's 7 days from the last full watering.

When I rains all bets are off. It seems like rain water irrigation is worth 10x of tap water irrigation. Watch the grass for signs of wilting and then water. It is much worse to water too frequently than to stretch it out. If you miss 2 or 3 weeks this time of year, the grass will recover. I had some golden brown St Augustine recover when I watered it - I though it was long dead.

Ok, so I've waited 4 full weeks, watered 1 inch per week in my troubled st Augustine shade spot and noticed more deterioration in health of my new st augustine on the front lawn. The cornmeal and actinovate definitely helped the dark spots and yellow patches of grass in the healthier areas, but the front lawn that's heavily shaded appears to still be seriously struggling:

compare this photo above to the original post and I've lost even more grass. For another comparison, look at the outlined box in the picture above. That grass is super lush/healthy and came from the same palette of palmetto st Augustine I installed 6 weeks ago.

Here's a closeup of the struggling front lawn below. the blades look much more healthy now, but I've lost so much density. There are a couple somewhat healthy thinner patches that make up probably 40% of the area and the remaining 60% looks dead.

I dont know if I should start over and apply fungicide and starter fertilizer before I lay the grass this time. Is it also too late in the year to lay new st Augustine?

Please advise. Thanks!

Competition from tree roots & shade are a 1-2 punch, especially is the sod was new. You can't do much about the roots, but you can clear out a lot of those tree branches.

I would not use a fungicide. I would use amino acids in the form of proteins. Soybean meal by itself is about 47% protein. These amino acids are what the biobugs use to build their bodies, and what the chemical fertilizers are missing. I would use biochar if you suffer dry spells. The medium rice grain works for top dressing. You can spray the powder. I would find out why that soil has nothing to offer the grass. The focus of soil tests can be targeted for a variety of aspects, not just the major, minor and micro nutrients. I would baseline them first, at least its a start point. One thing about thin roots, at least one reason can be cannibalization from a photosynthesis failure, where the last gasp is the plant eating its root resources in an effort to live. But some soil sucks. Do many roots grow on top of the ground, as in they grow upwards to get to the food? The tree roots might talk to you in this way, especially fast growers like maple, or willow. I would also point out that in heavy shade, cut your inputs by 2/3 at a minimum. No sun, no photosynthetic rpm from the plant engine because they are solar powered. You can easily give grass plants enough "stuff" to imbalance them. Mild stress even helps. Not enough water; A plant knows what to do to go find more water, if its underneath it at all, and roots will grow down in search of moisture. Next time though, try a different nursery, just in case they have issues. And read up on how to brew fungal tea. You quite literally could brew up a pencillin tea using the skin off brie cheese if you needed it. Better to have a host of normal fungi eatng all those bacteria you will feed though. They have roots deeper than the grass and bring water up.