Fall Lawn Concerns

I get many questions about lawns each fall. Grass struggles, and gardeners are confused as to what the true issues might be. Here are suggestions aimed at determining the exact causes.

Many people ask about what they should use on brown patch fungus. After talking with them a few moments, I realize that they’re seeing leftover chinch bug damage from the summer. Here are several loosely related pointers.

• CHINCH BUG damage shows up in hot weather (late June through early September). Even though we’re often balmy into mid-fall, it’s highly unlikely that chinch bugs will still be active anywhere but in deep South Texas. Their damage will always be in the hottest, sunniest part of the yard – never in the shade.

Since chinch bugs are no longer a threat by the time late September and October arrive, there is no need to apply insecticide for the rest of this year.

• BROWN PATCH is fungal. It begins as yellowed 18- to 24-inch patches of grass that turn brown within just a few days. Brown patch normally shows up in cool, moist weather.

The way you can tell the difference between brown patch damage and chinch bug damage: pull on the blades. If they’re rotted at their bases/pull loose easily from the runners, that’s brown patch. If they’re still firmly attached to the runners, that’s probably leftover chinch bug damage.

• GRUB WORMS are not as common as they have been in years past for whatever the reason. However, if you want to be sure that they are not involved, pull on the grass. If it comes loose from the soil, runners and leaves still attached, but without roots, that COULD be grub worm damage. Dig 1-foot square holes 6 inches deep. If you find 5 or more white grub worms per square foot, they would be the culprits. Let your nurseryman recommend the best insecticide for your lawn.

• TARR. Many people tell me in the fall that they have spread sphagnum peat moss over their lawns, thinking that their grass has Take All Root Rot (TARR). Sadly, they have very likely wasted their money. There probably isn’t one chance in a million that that’s the case. TARR is a cool-season, spring disease. Applying peat in fall won’t help whatever problem they’re having. It isn’t due to TARR.

• PRE-EMERGENT WEEDKILLERS will not be effective if applied in late September and after. The weeds will already have germinated and be growing. The next time to apply would be to prevent summer weeds, and that will come in late February or March, depending on where you live in the state. Mark your calendar next year for early September to prevent the winter and early spring weeds.

• “WINTERIZER” FERTILIZERS. October and after would be very late for feeding your lawn in the northern half of Texas. In South Texas, it would be fine to do so soon. Follow recommendations of a reputable soil-testing laboratory, and use a quality high-nitrogen or all-nitrogen lawn food.

• STARTING NEW TURF. October and after would be too late for sodding St. Augustine except along the Gulf Coast. Your next time will come in March in South Texas and April in North Texas. You can sod bermuda into the winter, if it’s your grass of choice, but there is some risk of its freezing or drying out/dying before it becomes established and firmly rooted.

• TREE LEAVES. Keep mowing at the recommended heights, and keep tree leaves picked up and put into the compost pile.