Low pH, Not Iron, Killing Centipede Grass: Lime Repeatedly

Centipede grass black/dead in areas; soil tests show pH 3.6–4.1 after some lime. Iron lowers pH, but pH is the real killer. Target pH 6.5. Apply 40 lbs lime/1000 sq ft, wait 30 days, retest. Repeat until pH 6–7. Then test every 60 days for a year. Likely need annual liming.