I'm going to venture a guess on this. I'm not super familiar with St.Augustine but usually when there's a problem like what you've described it's due to lack of diversity in your foodweb. It's sounds like you've been using alfalfa exclusively and only spot treating with the corn meal. Alfalfa is good green matter and as such is a good bacterial food. I think you need to incorporate more fungal foods into your system to help raise the fungal biomass of your soil. Corn meal is a good fungal food as is soybean meal.

By increasing the fungi in your sandy soil it will help retain water and should even out most of the color variences you're seeing. Do some research on how to brew a fungal dominant compost tea and apply at least once a month if not once a week. It will introduce a variety of fungi to your soil and the ones that your plants need they will support.

Are you waiting for the brown patch to occur before you treat? If so, try to take a preventative approach and treat all areas with corn meal before the brown patch rears it's ugly head.

Also, how deep are your roots? Are you seeing different root masses in the different color variations? Do the darker green areas have deeper roots than the lighter green and yellow areas? How about differences in soil texture?

Another way to raise fungal biomass is to do as DcHall suggests and lay the soaker hose on a trickle in different sections of the yard for a week. It creates an ideal environment for fungi to grow, however, I'm afraid that without frequent corn meal applications it may not be the fungi you want. My only other guess would be compaction issues but if you truly have sandy soil then that's not an issue (I'm jealous).

Greenjeans

I've been using alfalfa pellets and a product called Bradfield Organics Luscious Lawn & Garden (see below)

GUARANTEED ANALYSIS:

Total Nitrogen (N)..........3%
3% water insoluble nitrogen

Available Phosphate (P2O5)..........1%

Soluble Potash (K2O)...........5%

(Nutrients for this product are derived from alfalfa, molasses, sulfate of potash, and meat meal)

I cannot find Corn Meal at any feed stores in my area. I buy 40lb. crack corn and take it to my in-laws who have a Grain grinder and grind my own meal, which takes a long time. Will crack corn do the trick?

As far as the root depth/soil; in the areas of post brown patch they are very shallow and the blades are yellow. I live in West Central Florida and the soil is uniformly sandy.

Here is what I have available at my local feed stores.
Alfalfa Pellets
Calf manna
Cotton Seed Meal
Soy Bean Meal
Corn Gluten Pellets
Crack Corn

I'm going to suggest some things I hardly ever suggest, so stand back.

Is your sand still white? I'm going to suggest your sand (I hesitate to call it soil) is not growing a good herd of microbes. You might consider a VAM product to inoculate it with some of the fungi you need. It seems to work especially good in sand under extreme conditions - just like yours.

In addition to that you are a super candidate for frequent sprayings of compost tea. Compost tea brings fresh microbes to the soil. I would spray about sundown.

Another thing I never mention is molasses. With pure sand you can't get enough bacterial food. Molasses is great for stimulating more microbes. If you have a farm and ranch coop nearby you might be able to find liquid molasses for about $0.10 per pound. A gallon (in your own container) would cost you about dollar. The farm and ranch rate is a gallon per acre which converts to 2 ounces per 1,000 square feet but you could double or triple that. Or spray 2 per 1,000 weekly.

Any of that stuff you have at your feed stores is good. You can use all you are willing to buy and apply. If you're getting fungus on a regular basis, you should use corn meal at at least 10 pounds per 1,000 every 60-30 days to prevent it.

By the way that Bradfield product is super. They make good stuff.

Oh and be sure you don't remove any clippings. Your lawn needs all the organic matter it can get.

skoot_cat,

I have a St. Augustine lawn, but it's sitting on top of clay. I would recommend taking a soil sample of the affected area and sending it in for analysis. DCHall has got a link somewhere on the forum of a place that will help do an analysis slanted toward organic care.

Another possibility is that you are lacking iron. Greensand is a good source of iron that is only released after the microbes process it.

It might be useful, too, to have a nematode assay done and to have an analysis for SAD (St. Augustine Decline). In some locations, it has become very prevelant.

Cracked corn performs the same as corn meal in all respects. The only drawback is you may have some little corn plants poppin' up on occasion.

The Bradfield organics is mostly bacterial food. I'd loose it and go with the soybean meal were I given a choice from your list. Go with soybean meal and cracked corn a little more frequently than you had been with the alfalfa. Save the alfalfa for planting and rooting seasons when it'll give the most benefit. Don't be afraid to use different grains throughout the season. The more diverse your grains the more diverse the biology. Use that cracked corn religiously until your brown patch problem is gone. Start applying actively aerated compost tea to introduce more beneficial fungi to feed on the new food you'll be giving it.

Greenjeans

I learned something new today! Didn't know that about bacteria and sand. I stand corrected. Sorry for improper advice but please read my disclaimer in my first post. : )

Greenjeans

Does the brown patch occur in the same area year after year? If so you might wish to find out if the area holds moisture moreso than the rest of the lawn and remedy that condition. If the brown patch occurs at random then it is being spread; the lawn mower can do it if it is used when the grass is wet. Water is almost a requirement for the disease to spread. Watering to 1 inch twice a week in summer in your area sounds like a lot of water- especially in July and August. But as long as there is no run off when you irrigate and the irrigation is done in the morning rather than the evening, you might be OK. Finally, consider the possibility that it might not be brown patch. That would leave a couple of insect pests and a host of environmental conditions or cultural practices.

Many Thanks for all the feedback.

As far as my soil type, its not pure white sand its more light gray an loose, if that helps.

I had and analysis done at my local extension office and they confirmed it to be brown patch.

What happens is First I get sod web worms, then the areas that the web worms have damaged comes the brown patch.

As far as water, by the 4th day the leaves start to curl in lots of areas. There will be an irregular patch of curled dry leaves and right next to it the sod looks fine. I can't figure it out.

See link below for Pics

Here is a link that might be useful:

Great picture! Thanks. I see tufts of dark green spots. Do you have a dog? Or are these the spots that have not yet been affected by the brown patch??? If you have a dog and have those tufts, then that indicates you are seriously behind on your fertilizer. It would indicate that the urine from the dog is providing more fertilizer than you are.

I'm not surprised you water that much. You said you had short little roots. What will happen eventually, once you get the disease under control and get some microbes working for you, your roots will grow much deeper and will be able to get moisture from deeper in the soil/sand. Hopefully you'll be able to back off on the watering some, but not now.

I haven't seen anything that would make me change the frequent corn meal application suggestion. I guess I would tend toward monthly applications until your sand starts to turn dark brown. I use white sand as fill in my yard. Eventually it will turn very dark with organic matter.

Here's a link to the Texas Plant and Soil Lab. Tell them you are organic and they will help you out. These folks have performed miracles in agriculture. The reason they can perform miracles where others have failed is they use the same chemicals for testing that the plants use in the soil. They don't use hydrochloric acid to dissolve everything and see what's left. They use carbonic acid like that found in the soil. The result is that when they tell you what soil minerals are available to your plants, they can back up their recommendations with analysis of the plants themselves to show what minerals are being taken in. You can't do that with hydrochloric acid testing, and that is why I'm so negative on university soil testing. Universities know how to do the tests like TPSL does, but they choose not to. Even if you demand carbonic testing, they have to $$$pecial order the materials and refresh themselves (i.e. learn) on how to do the tests. And then they have no database using carbonic acid, so they cannot interpret the results. Furthermore, they are still going to suggest you add chemicals to your garden because they are, by and large, unaware of what organic fertilizers are. Whereas the TPSL routinely does carbonic acid testing so they order their chemicals in bulk to get the cost break, they know how to do the tests, they know how to interpret the tests, they provide more testing than the universities do, and they will give you recommendations in line with an organic program. If I recall they charge $35 which is a few dollars more than the universities.

Here is a link that might be useful: Texas Plant and Soil Lab

Yes, I have a large dog. Good call.

Will cracked corn have the same benefit? It takes me so long to grind my own, (yes I grind my own) my local feed stores do not carry it. They have whole and cracked corn.

Should I use anything else or just the corn monthly.

Great Link Texas Soil Lab, I will be send my sample very soon.

Thank You and everyone for the great feedback

Cracked corn will give same benefits but might take a bit longer to decompose. When i think about it, i'd rather go with cracked corn although I haven't used it. Corn meal is just too messy for windy days which is pretty much everyday. I'd like to use rotary spreader to spread evenly and faster.

Corn meal is pretty weak fertilizer so you might want to use soybean at the rate of 15lbs per 1000 sqft every few months to give your grass a boost from extra protein (nitrogen). You can also add alfalfa at the rate of 10lbs per 1000 sqft while reducing soybean rate to 10lbs per 1000 sqft.

Cracked corn will give you corn plants, too, so don't be surprised. They mow off easily and do not return so they're not a very tenacious weed.

Which test do you ask TPSL to do, I'm guessing the 1st one?

Standard Top Soil Analysis, the first one, $30.

Would you mind letting us know if you like their results??