Well, I'm growing st augustine on limestone rubbles which is very alkaline and I didn't need sulfur to fix the problem. You still need to feed your lawn with something to encourage fungal growth like soybean meal. Try Scott's organic choice and see if it did anything. Just anything... Spray 2-4oz of unsulfured molasses on your lawn (grocery stores sell them). Try Seaweed liquid that you can get from Lowe's and spray on them with Ortho dial. See what happens. If nothing happens at the end of the summer then you sure have a problem. I never needed a soil test for my lawn where sulfur would absolutely do nothing for high PH . It's like a drop in the ocean. No effect at all.

Which st augustine variety did you get?

Another thing...

How many pound of greensand did you put down per 1000 sqft? I think you would at least 40lbs per 1000 sqft to see any effect. I put down a lot during the first 2 years (I would guess around 120-200 lbs per 1000 sqft)and not so much this year and my look has never looked better (entering 3rd year).

I haven't put down anything this year because I was waiting to do the soil test. Even without fertilizing with meals, I am already cutting the lawn twice a week at 4".

Here is what it looked like last year. Last year I put down 40lbs/1000sqft of greensand 3 times over a 3 month period and saw no appreciable results. I also applied the seaweed liquid as well. To try and minimize the chlorosis I don't irrigate as I believe it gets enough runoff from the flower beds and normal rain fall.

I am looking to try something else because the basics aren't working.

As I said in the other thread, I don't think adding sulfur is effective when done on a lawn. In order for sulfur to be effective, it needs to be incorporated into the lawn.

Since you can get greensand, I would use that. If it didn't work last year, it could be that it takes more to be effective than you were using.

Something that provides a very temporary change is to spray water soluble iron directly on the leaves. However, that should only be done when it is cool. To increase the effectiveness of the foliar spray, add some shampoo to the spray bottle.

The only other thing I would do is to add as much organic matter as possible.