Bought a foreclosure 2 years ago with a badly neglected lawn. I live in Tampa, Florida. The lawn is a mixture of floratam and sapphire. My question is the area with the sapphire has yet to fill in (put down sod last year and grubs nearly destroyed it) and I have been fighting crabgrass, nutsedge, dollarweed and in the summer kyllinga. The worst area of my lawn has no protection from the sun (full southern exposure) and has a slight slope to the street. I have used pre-emerge in the fall and applied it this year mid february and atrazine for the weeds but each summer has been pretty bad. This area gets choked by the weeds. I was wondering would it be a good or bad idea to put pine bark fines in the barren areas? Also, wondering if fertilizer requirements are higher for sapphire than floratam, and when should I put down grub killer? (sapphire is still not as green as floratam right now) I water twice a week per the water restriction we have. I mow at the highest level the mower will allow. Other than this area which is a 1/3 or the yard the grass is beautiful. Products I use are scotts fertilizer (fall and spring), Image, milogranite(two times in the summer) and halts(spring). I checked into starting an organic program but about choked when I saw the price. I don't have soil I have pure florida sugar sand Oh, I also have nematodes. Please tell me what I'm doing wrong.

Christi