Our warm-season grasses don’t like low temperatures. In fact, some may show some off-color because of chilling stress that might start from 54 to 60 degrees F, according to LSU AgCenter horticulturist Dr. Tom Koske.
Early chilling damage can appear as an overall tan or a blotchy, camouflage mottling of the turf. Dead foliage is dry and not the yellow, slimy tissues that are seen with brown patch disease.
"We all should expect our warm-season grasses to discolor with the first frost," Koske says, adding, "When there’s a heavy frost, keep traffic or play from the turf until temperatures reach mid- to upper 30s." He explains that the frosted leaf blades will break off from fracturing the ice crystals in the leaves. Melting can be hastened by applying a light irrigation if temperatures are not below freezing.
If there’s a hard freeze, turf is more prone to extensive damage from traffic. Here the leaf and shoot cells will rupture where squashed, leaving dead areas in the shape of foot prints or tire tracks. This is also true of lawns that were irrigated and frozen over or those covered by an ice storm and then trafficked or mechanically stressed.
Protecting turf from winter starts in September when we ensure the sod has lower nitrogen fertility and adequate potassium. If you suspect the lawn is short on potassium, apply some potash while the grass is still growing and can take it up. December is way too late to winterize the lawn.
For now, try a light irrigation to knock off frost, or apply lightweight, porous turf enhancement covers, to hold extra soil heat on the sod. Apply and remove as needed for frost threat and play access.
If the grass is still growing a little, raise the cutting height a notch or two to get more foliage cover. This foliage cover can give extra protection from freeze damage.
In the event of a freeze or hard frost, it is important to keep all traffic off the sod if winter kill damage is to be kept to a minimum.
For related topics look for Gardening and Get It Growing links in the Feature section of the LSU AgCenter Web site: www.lsuagcenter.com.
The LSU AgCenter and the LSU College of Agriculture