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.

" 1-2 hours of direct light a day " You will not get any variant of any type of grass to grow successfully under these conditions that will ever please you. It'll sprout. It'll grow for a while. Then struggle. Then die. 1-2 hours of sun per day is deep shade to mostly shady. All grasses are at least part sun--absolute minimum and strongly prefer part shade to full sun. People will tell you that you can grow grasses in lower light conditions. This is sort-of-correct, with massive amounts of care and constant coddling. Sometimes. But tree edges aren't conducive to that, and it usually involves a lot of northlight and/or reflected light. You don't seem to have that. My advice? Embrace things like bleeding hearts and other very pretty low light plants that are beautiful and appropriate to moist, low-light areas. Or embrace the moss (edit to remove incorrect info). Fun fact: Moss killing is really reliable if you're out spraying your lawn with iron sulfate. Your standard 2-4 oz per gallon solution, sprayed on moss, will take it right out. Dish soap...not so much unless reasonably highly concentrated, enough so to be an issue for other plants (salts will desiccate many other plants as well as mosses, particularly younger and more tender ones). Save a plant, green it with a light dose of iron instead of wasting the Dawn in the yard for that particular purpose. I use a quick shot of iron in the gardens in fall and let the moss bodies decay over winter, a warning to other mosses to beware. :-) Plus I get a little moss on the north face where the hose sits. No biggie, but if I'm standing there...

Your lawn fertilizer guy is hilarious. Fire him now. The problem is you. You're overwatering. See all those circles of dead grass? Those are typical of fungal disease caused by overwatering. When the disease shows up with circles like that, it is referred to as fairy ring. Your lawn fertilizer guy should know that, so since he doesn't, fire him. He's incompetent and should be in another business. If he's part of a large business, the business is inept in their training. I'm guessing they have already fertilized your yard once this year. If they have, be sure to fire them. They should have waited until the end of May to fertilize. You can recover right now by using a fungicide. I don't use fungicides so I can't help you select one for your area, but I can help you with proper watering. Deep and infrequent is the mantra for watering. Deep means 1 inch all at one time, not spread out over a week. Put out some tuna or cat food cans and turn on your sprinklers. Time how long it takes to fill all the cans. That will be your watering time, every time you water, from now on. My oscillator sprinkler on full sweep takes 8 hours to fill the cans. High flow inground systems take as little as 15 to 20 minutes to fill all the cans. You'll have to determine the time for your setup. As for frequency of watering, that depends (mostly) on the daytime high temperature. Of course Mother Nature will deliver Her dose of water, so you should be able to skip watering for at least a week after a soaking rain. There have been a few years recently when I did not water until June or July because of some well timed rain storms. This year is different for us. The ponds all around us are full, but my little area has been skipped over. Anyway, with temps below 70, deep water once a month. Rain almost always takes care of this. With temps between 70 and 80, water once every 3 weeks. With temps between 80 and 90, water once every 2 weeks. With temps from 90 to 100, water once a week. That should work. If you see the grass drying out at day 6 in the summer, set it for a 6-day schedule instead of 7 days. In NO case should you ever water established turf every day. Also make sure you are mowing the grass at the highest setting. Correcting the watering and setting the mower up will fix your issues. So the problem with the appearance was caused by you (overwatering). There's nobody else to blame as much as I would love to blame the lawn fertilizer guy.

i'm assuming you want pump based because you're using pre-mixed liquid fertilizer or rainwater, or simply have no way of getting a garden hose over. And i'm also assuming that you've tried premade drip irrigation kits from home. I'd consider trying these https://www.amazon.com/Axe-Sickle-Emitters-Adjustable-Irrigation/dp/B01HHJB6I6/ref=sr_1_2?dchild=1&keywords=sprinkler+head+drip&qid=1594666912&s=lawn-garden&sr=1-2 I have these for my system and can adjust at each head which helps. Ultimately nothing is automatic, and debris can clog heads to make them not perfectly balanced as well. you also seem pvc saavy, so to evently distribute the water to the sprinkler heads, i'd also use this https://www.homedepot.com/p/DIG-1-2-in-Riser-Adapter-with-1-4-in-Micro-Tubing-Barb-R67/100126262 Lastly, in order for you to achieve even-ness, your pump (accounting for head height) needs to overwhelm the output. If your basic water pump is not strong enough, you may consider a pressurized pump https://www.amazon.com/Camptemp-Diaphragm-Priming-Pressure-Adjustable/dp/B07QWJR1XW/ref=sr_1_24?dchild=1&keywords=diaphragm+pump+110&qid=1594666812&s=lawn-garden&sr=1-24 You can obviously buy faster pumps (3ph), but cost more. Looking at your setup, something cheap and simply would be best. Even though diaphragm pumps don't push a lot of water, These cheap diaphragm pumps can push water at very high pressure to ensure even-ness. Keep in mind the cheap ones are also loud. I have all kinds of pumps, but my personal favorite diaphragm pump is https://www.amazon.com/SEAFLO-Pressure-Diaphragm-Variable-Reduced/dp/B01CQ7DD0S/ref=sr_1_4?dchild=1&keywords=seaflo+water+pump&qid=1594667472&sr=8-4