Bare spots in St. Augustine

[jbj]

I have several bare spots in my St. Augustine in my back yard where the grass has just gone away. I applied corn meal last year thinking it might be a fungus problem. I have also attributed this to heat and drought 2 years ago and then spring/summer floods this past year. I also have about 30 mature oak trees that I have just worked on to get more sun to the grass. The problem is that where these spots are bare, undesirable junk is taking over. Should I completely cover these bare spots with compost and/or mulch and then sod or plug new grass in the spring? Thanks for any and all responses.

[Dchall_San_Antonio]

St Aug will fill if there is nothing wrong with the soil. I have bare spots, and have had them for 10 years so far. I know exactly why, too. Ten years ago I built a fort for my daughter out of treated lumber. I set the saw horse directly above where the bare spot is still. The treated lumber sawdust killed the soil biology and I can't seem to do anything to fix it. I thought it was cured last year, but I was fertilizing last weekend and noticed the bare spot was back. So the question is, do you have a chemical "spill" issue in your bare spot? If so, compost is the place to start. You don't need to cover it, just dust it. Then make sure there is moisture, molasses, and corn meal, probably monthly, to feed the microbes.

As a last ditch, you could dig out the soil and replace it. I'm afraid that's my next step.