Wish I had more info for you since your plan sounds much better than a toxic, chemical lawn. I used to be more into grass/mowing in OH, but as hot as it is here, I just don't want to mow any more than necessary, no idea how to cultivate the grass here on purpose. And even right after mowing, it's not comfortable on bare feet, blah. We cut it as low as possible, as rarely as possible, and rejoice when drought or cold makes it stop for a while. I'm hope someone who appreciates fertilizing/cultivating grass will pop by with something actually helpful to answer your questions. Good luck!

One application of fungus control will not kill the fungus. You need multiple applications 2 weeks apart. Also important is what time of day you are watering. If you are only watering for 15 minutes (which is not really long enough to get water down in the soil) you should be able to water during the early morning so the grass has a chance to dry out. Does the fence shade the spot? Can you eliminate watering that area?

Lyn you're talking about corn meal, not cottonseed meal. I almost never mention cottonseed meal. But if I do a search/replace in your post and sub in corn meal, then I would agree. I'm extremely supportive of using corn meal to control fungus. In fact the performance of corn meal in treating fungal disease in turf is the main reason I converted from chemicals to organics. That was in 2002. I've been using it successfully every year since. And yet Texas A&M University is publishing everything they can to squash the idea that corn meal has any effectiveness. To me that's simple misdirection of education. If they can't make it work, they need to come look at my lawn and figure out what they're doing wrong. I have some ideas about what they're doing wrong, but haven't seen their research. The silly thing is that it was TAMU who first published the idea that corn meal was an effective tool against disease (in peanuts). That was back in the 90s and they've been fighting against themselves ever since. Anyway you can't use corn meal once you've used a chemical fungicide. Corn depends on the growth of a predatory fungus for its effectiveness. If you have a fungicide down then that beneficial fungus will not thrive in sufficient populations to do anything. If it has been several weeks since you used the fungicide you could try applying a very light dusting of compost to restore the beneficial microbes and then the corn meal. >>green edge which is 100% organic slow release I just want to comment on the idea that organic fertilizer is slow release. Chemical fertilizers work on several principles but generally those are chemical imbalances forcing the fertilizer into the roots as quickly as the roots will take them in. Organic fertilizer is made from food materials like corn, wheat, soybean, cottonseed, alfalfa, etc. That food becomes food for the living microbes (bacteria, fungi, microarthropods, and others) at the surface of the soil. As the original food/fertilizer decomposes from the microbes, then subsurface microbes decompose the byproducts from the first level decomposers. The process of a succession of microbes decomposing previous decomposers is so complicated it is referred to as the soil food web. At about 3 weeks after the original application of food/fertilizer to the surface, the resulting byproduct of decomposition is actual NPK type of plant food in a form akin to what comes in a bag of chemical fertilizer. So it is not that organic fertilizer is "slow release" so much as it just takes a really long time for the biology of the soil to convert the original mammal food to plant food. But this is the way Mother Nature has designed the process. It has worked for a really long time. On the other hand, chemical fertilizers that call themselves 'slow release' are caused to be that way by coating them in a slow dissolving chemicals.

If you had not already applied a chemical fungicide I could have helped you. Recheck the label on your fungicide to be sure it works in the temperatures you are getting now. Most tell you to not use above 80 or 85 degrees F. If that's on your label then stop using it now. The easy solution to the problem, had you not already used the chemical, is to apply ordinary corn meal at rate of 20 pounds per 1,000 square feet. If you cannot find corn meal in 50 pound bags at your local feed store, you can also use cracked corn or corn flour from the grocery store. You can find it in 25 pound bags in stores that cater to the Hispanic community. Corn meal works by attracting a beneficial predatory fungus which kills the disease fungus. So if you have already used a fungicide, then the beneficial fungus is gone. If the temps are too high for your chemical fungicide, then wait 2 months and try the corn meal. Or you might be able to speed up the recovery by using compost at a rate of 1 cubic yard per 1,000 square feet along with the corn meal. Compost contains the beneficial fungus you need and will reinoculate the soil with it. Here are before and after pictures using corn meal. The grass in the pictures were in deep filtered shade of a large live oak tree. That was about as dense as it ever got in that area with zero hours of direct sunlight. St Augustine does not get thatch except under the most ridiculous maintenance practices. It would require daily watering and weekly fertilizing with a liquid spray. I have seen it, but only on one yard. And as soon as the management on that yard went back to normal the thatch disappeared. That lawn was growing entirely on top of the soil. Aerating won't help. Would you characterize your soil as sand or something else? Okay I just read back. This is Floratam? Floratam is the most disease resistant variety of St Aug. It is also the most sensitive to chemicals. Stop mowing it low and let it grow up for several weeks until it is higher than your mower's highest setting. Then mow every 2-3 weeks. The idea is to grow deeper roots which can get nutrition from deeper down in the soil/sand. You should see the new Floratam growing in at a faster rate than the disease can progress. You MIGHT still need corn meal to get rid of it, but tall Floratam in full sun can outrun a disease. Deeper rooted Floratam needs much less water and even less fertilizer. I have grown it up to 32 inches high in the Texas heat and drought, and it never needed either irrigation or fertilizer over a 2 year period. I'm not suggesting you do that, but the grass loves being tall. Here are some other tips to keep disease out of your lawn. Never put anything on the grass and leave it overnight. No toys, no yard clippings, no trash, no yard tools, nuthin that would cut off the airflow overnight. Disease will form in the morning dew if the dew cannot evaporate easily. Also be sure your soil drains well both downward and outward so it never puddles anywhere. You can improve downward percolation by spraying the entire yard with any clear shampoo at a rate of 3 ounces per 1,000 square feet and follow that up with 1/2 to 1 inch of irrigation or rain. And one last question: what is your watering regimen? How often and for how long do you water when it is not raining?