When should you apply ammonium sulfate?

NOW. In Arizona, apply a high quality grade of ammonium sulfate to your lawn in the first two weeks of March, then water in deeply. Apply the ammonium sulfate according to package directions. Over indulgence with this product will kill your lawn. Furthermore, two weeks after applying ammonium sulfate, fertilize your lawn with a combination of Scotts turf builder and ammonium sulfate and water in deeply. You will have a beautiful lawn with in three weeks. DO NOT apply either the ammonium sulfate or Scotts turf builder on a newly seed lawn until after the third mowing. Good Luck. Sandy of Sahuarita, AZ