Fall Diseases - Brown Patch and Take-All Root Rot are two fairly common fungal diseases that affect St. Augustine grasses. With our recent rains and high humidity, both could become active once the sever, intense stress your lawn has endured due to the summer heat gives way to milder, wetter weather. If you're noticing dying, brown circular patches, you can apply a granular or liquid fungicide to combat disease. If you have a lawn sprinkler system, set the schedule to mornings only, because night and evening watering encourages fungi to flourish.
Pre-emergent Herbicide - Fall and winter weeds such as henbit and chickweed may be best controlled now with a compound which prevents weed seed germination, such as Balan, Amaze, or Dimension, or XL2G. Read label directions and follow use rates for best results.
Feeding - In order to "over-winter" lawn grass, an even application of a 3-1-2 ratio fertilizer or "winterizer" blend fertilizer now will give a strong boost to your spring growth. However, don't over do it! Lush, thick growth is more susceptible to fungal problems now and frost later, so a light application is best.
Other fall lawn tips:
- Water during the winter - 1/2 inch per week if rainfall is lacking.
- Aerate if you have new sod or soil that has been packed over many years of foot and tire traffic.
- Don't "scalp" your lawn in the fall - mow grass to a 2" height so it can insulate and protect itself.
- Get a soil test, available from the Texas Agrilife Extension Service, and apply fertilizer and/or lime as indicated.
(Excerpt from www.easttexasgardening.tamu.edu, Bill Kelldorf, Smith County Master Gardener)