We are fast approaching fall and we will soon see ads and products that tell you to Winterize your lawn. This is not something we need to apply to warm-season grasses. So, the question to follow is: “What is a warm-season grass?” The answer is, your grass is a warm-season grass!
Centipede, Bermuda, St. Augustine, Zoysia are all warm-season grasses. The only cool-season grass grown in the state of Georgia would be Tall Fescue and it cannot grow in our area. So, when you see the product promoting stronger, a deeper root system but also has nitrogen in the bag, please do not apply it! No nitrogen should be applied to our warm-season turfgrass after Aug. 15, not even at low rates. The nitrogen stimulates the grass at the wrong time of the year. Shorlty the plant will be shutting down and sending nutrients to the root system. If you were to apply nitrogen, you would “trick” the grass into growing more leaf blade. This confusion on the plant could cause harsh winter injury and delay green up in the spring.
Now, if you truly want to help your warm-season grass this winter you can apply a fertilizer with only Potassium. If you read a fertilizer label and it shows 10-10-10, those numbers mean Nitrogen (10)-Phosphorus (10)-Potassium (10). So, a fertilizer like 0-0-7 is a great option that will provide potassium to the root system of your warm-season grass. This allows the plant to build a stronger root system to absorb more moisture and nutrients.
Many of these potassium fertilizers also come with a great preemergent herbicide to help control annual winter weeds like Poa or annual bluegrass. This is great because the timing for a pre-emergent herbicide in the fall and a potassium application align. The best application time is in October.
So, you can “winterize” your yard but be on the look out for misleading advertisements. Make sure the products you put out or the landscaper do not have nitrogen or phosphorus in the mixture. An application of potassium for the root system can be beneficial.
For more information or questions contact UGA Extension-Effingham County Ag Agent Sam Ingram at 754-8040 or firstname.lastname@example.org.