Lawns in Louisiana continue to grow into the fall but it is getting time to put up your fertilizer spreader for the winter. Lawns should continue to be mowed and watered as needed well into fall but as nighttime temperatures dip into the 50s, warm season lawn grass growth will be reduced and go dormant as temperatures get even lower. Fertilizing lawns correctly can produce benefits next spring but applying fertilzer incorrectly may cause problems. Fertilizing warm season grasses -- St. Augustine, Bermuda, Zoysia, Centipede -- during the fall with high nitrogen, summer-type fertilizers or winterizers containing nitrogen are not recommended for southern lawns. Stimulating fall growth with nitrogen leads to increased brown patch disease and winter kill.
The only fertilizer that should be applied in the fall is potash. Muriate of potash, 0-0-60, may be applied in September or October to provide increased cold tolerance. Apply at a rate of 1-2 pounds per 1000 square feet. For extra color on fall turf, apply a foliar iron spray. This will help extend greenness into fall.
Fall is the best time to get your soil tested by the LSU AgCenter. Soil testing is the first step to a beautiful lawn and is the best way to determine exactly what your lawn needs to become thick and healthy next spring.
Soil samples should be 4 to 6 inches deep as well as a composite of samples collected from several locations in the lawn. Mix this well and take a pint to your local extension office.
Results will be sent to your home address and/or emailed in about two weeks. Sample results may indicate that lime is needed to increase soil pH. Fall/winter is the best time to apply lime since it takes several months to react with soil and adjust to proper pH. You can contact your local extension office to assist with interpretation of results at 318-728-3216 or drop by at 702 Madeline Street, Rayville, Louisiana.
The LSU AgCenter and the LSU College of Agriculture