Most fall lawn advice is written for tall fescue, and a lot of it is the opposite of what bermuda and zoysia need. If your lawn is a warm-season grass, here's how to get it through fall and set it up for a strong green-up next spring.

What's happening to your lawn

Bermuda and zoysia love heat. As nights cool off in September and October, they slow down, and after the first hard frost, usually late October or early November around Raleigh, they go dormant and turn tan for the winter. That's normal and healthy. The roots are alive; the grass is just resting.

Don't feed it nitrogen in the fall

This is the big one. Fescue gets most of its fertilizer in fall. Warm-season grass should get little to no nitrogen once it starts slowing down. Late-season nitrogen pushes soft new growth right before winter, which can mean more winter injury and more disease, including spring dead spot in bermuda and large patch in zoysia.

What a warm-season lawn does benefit from in fall is potassium. A low-nitrogen, high-potassium feeding before dormancy helps the grass handle cold and come back stronger. That's the late-fall visit on my warm-season program.

Stop the winter weeds before they start

When your bermuda or zoysia goes dormant, winter weeds move in: Poa annua (annual bluegrass), henbit, chickweed and others. On a tan dormant lawn they stand out like a sore thumb, and they set seed for next year.

The fix is a fall pre-emergent, timed to when the soil cools below about 70°F, usually mid-September to early October here. It stops most winter weeds from ever sprouting. Anything that sneaks through can be spot-treated over the winter while the grass is dormant.

Watch for large patch on zoysia

Large patch is a fungal disease that shows up as big, circular tan or orange patches, often in fall and again in spring as the grass greens up. Zoysia is especially prone. It's worst on lawns that stay wet: heavy irrigation, poor drainage or thick thatch. If it has been a problem before, a preventive fungicide in fall, when soil temperatures fall through about 70°F, does far more than trying to cure it after the patches appear.

Mowing and watering

Keep mowing at your normal height until the grass stops growing. Don't scalp it short going into winter.
Cut back on watering as it slows down. Dormant grass needs very little water, and overwatering in fall feeds disease.
Keep leaves off. A dormant lawn under a mat of leaves can come out of winter thin and patchy.

Save aeration for late spring

Core aerating bermuda and zoysia in fall just opens the door for winter weeds without giving the grass time to recover. The right time is late spring into early summer, when warm-season grass is growing hard and fills in the holes within a couple of weeks.

The short version

No fall nitrogen. Potassium before dormancy instead.
Fall pre-emergent for winter weeds.
Preventive fungicide if large patch has been a problem.
Normal mowing height, less water, leaves off.
Aerate in late spring, not fall.

Curious what's going on in your lawn? Look it up in the lawn library, or send me a photo through the free photo checkup.

Fall Care for Bermuda and Zoysia Lawns in Raleigh