How Much to Irrigate?
Regardless of the turfgrass species about 1 in per week or 1 to 1 1/2 inches per week in clay soils from May to September. However, because of the lack of rain in September, watering should continue through October.
Warm Season Grasses:No Winterizer!
Do not be mislead by advertising. Do not apply nitrogen after September 1st even at low rates. If so you will be stimulating the grass at the wrong time. Roots may need Phosphorus and Potassium but not Nitrogen. Use 0-0-20 or 0-060 to apply about 1 lb. of potassium oxide per 1,000 square feet of lawn.
Soil Sample Now
If the pH needs to be raised, then add a calcitic or dolomitic lime product.
Weed Control
Poa Annua weed
Preemergence herbicide application for south Georgia is from September 20 to October 15 and February 10 to March 1. Early application is the best because with warm soils seeds are likely to germinate. There is still time to get it out and water it in thoroughly. No rain and no irrigation will lower the longevity of the herbicide through the year.
Source: Turfgrass Management Seasonal Practices by Dr. Clint Waltz, Turfgrass Extension Specialist, University of Georgia