Let’s face it, lawns sometimes are forgotten when it’s time to prepare your landscape for winter. There are some precautions you can and should take to get your lawn ready for the colder months and to ensure your turfgrass is in good shape when the soil warms up next spring. These precautions often are lumped into the term “winterizing,” an attempt to toughen up plant tissue by slowing down growth and beefing up plant levels of potassium.
Warm-season turfgrasses are Bermuda, zoysia, centipede and St. Augustine. Tall fescue is considered a cool-season turfgrass. Turfgrass calendars can be found at https://bit.ly/3QpG5aV.
Research done through the years has shown that higher levels of plant potassium enhance tolerance to a broad range of environmental stresses, including, but not limited to, cold damage. A good strategy to encourage healthy turf is to maintain high levels of soil potassium throughout the growing season. When soil-test levels of potassium have reached a high level, maintain that by applying two-thirds to one part potassium fertilizer for every one part of nitrogen supplied when fertilization is done. While this is not an exact calculation, it is a good rule
Phosphorus — the middle number on a fertilizer bag — usually is not a concern in the fall, as an application now probably would just promote winter annual weed seed germination.
It’s always helpful to do a soil test. Visit https://bit.ly/3RzED7h for testing instructions.
For those with a less-than-ideal lawn fertility program, here are some end-of-season tips:
- Minimize nitrogen fertilization on warm-season turfgrasses as we approach fall. Nitrogen should be applied in the fall only if you have a fescue lawn. Reducing nitrogen fertility slows growth, allows the grass to toughen and reduces fungal diseases like brown patch.
- Finish the growing season with a fertilizer high in potassium. If applying only K2O (potassium oxide) to avoid extra fall nitrogen, use 1 to 2 pounds of muriate of potash (0-0-60) per 1,000 square feet. Apply to a dry lawn and water in.
- Maintain adequate moisture in the fall. We often want to forget lawn care by this time. But fall can be one of our driest times of the year, and turf still needs to store food now for the long winter dormancy.
- Keep an eye out for yellowing areas that would indicate brown patch disease and treat with fungicides, as needed. Remember, if these areas die off in late fall, they still will be dead next spring.
One last warning. Too much of a good thing often is bad. Excessively high amounts of potassium fertilizer might lead to foliage burn (salt burn) or cause competitive inhibition of other soil nutrient uptake.
The Master Gardener Volunteers of Cobb County supports the University of Georgia Cooperative Extension Service and strives to improve the quality of life in our community by delivering research-based horticultural information, educational programs and projects.
– Master Gardener Volunteers of Cobb County is a part of the University of Georgia Extension.