Winter Lawn Care and Dormant Lawns, by Zone

Dormant, not dead

Warm-season grasses — Bermudagrass, zoysiagrass, centipedegrass, St. Augustinegrass, bahiagrass — grow best in summer, go dormant in the fall at the first heavy frost, turn brown, and green up slowly the following spring (NC State). Buffalograss turns straw-colored from mid-fall to mid-spring and greens up quickly. Cool-season grasses remain green through most of the winter. If you are not sure which you have, see cool-season vs warm-season grass.

A dormant lawn needs very little: no mowing, no nitrogen, and water only in a long dry spell. Clemson keeps fallen leaves off it, since they block the light the grass needs to store food before it goes dormant.

Watering a dormant lawn

Clemson says most of South Carolina gets enough winter rain to avoid winter drying, but not every year: it watches the rainfall and waters a dormant Bermudagrass lawn if no measurable rain falls for 3 to 4 weeks, especially when warm, bright days come before nights forecast in the low 20s °F. The moisture keeps the growing points warmer and prevents crown death. It also warns against keeping a clay soil saturated all winter.

For lawns let go dormant in a summer drought, NC State waters about a quarter inch every three weeks to keep the growing points hydrated, and Clemson about half an inch every 3 weeks for dormant tall fescue.

The five kinds of winter injury

University of Minnesota Turfgrass Science names five, written for Minnesota lawns:

• Desiccation: winter wind dries out grass that has no snow cover, often on slopes where snow has melted or blown off.
• Ice encasement: a layer of ice around the plants stops the exchange of gases, most often in low spots that hold water.
• Crown hydration: a thaw lets the plants take up water, and a sudden hard freeze afterward ruptures the cells in the crown.
• Low temperature kill: most often after a warm fall followed by a sudden turn to freezing, before the grass has acclimated.
• Snow mold: a disease that attacks under snow but seldom kills, and usually just delays green-up.

Snow mold

Iowa State says gray and pink snow mold follow long snow cover on ground that is not fully frozen, and show as snow melts: round, straw-colored patches, matted, with pink or gray fungal growth. Gray snow mold patches can be a few inches to a few feet across, pink ones usually under six inches. The damage is usually not serious; rake the patches gently to help them dry, and overseed any that do not recover.

To prevent it, University of Illinois Extension keeps mowing until the grass is fully dormant, uses slow-release nitrogen rather than fast-release in early to mid-fall, keeps thatch down, and clears leaves and other debris. Both Iowa State and Illinois say piled and drifted snow makes it worse: spread out large piles and use snow fencing where it keeps coming back. Iowa State says fungicide in late fall is for golf courses and other high-value turf; if you use any pesticide on a lawn, follow the label and your state’s rules.

Voles

Illinois says voles — meadow mice, 4 to 6 inches long and brownish-gray — make runways under the snow as they feed on grass blades and roots, and the winding trails show when the snow goes. Moles are not active in winter, so the damage is not theirs. Lawns usually fill in as spring warms; severe damage may need overseeding. Mowing until the grass is dormant, to a final height of about two inches, and clearing heavy growth near the lawn leaves voles less cover.

Feeding and liming in winter

• Warm-season lawns: no nitrogen. NC State says to avoid late fall or winter nitrogen on them to reduce winter injury, and Clemson waits for full green-up in spring.
• Tall fescue in the South: February. Clemson feeds 1 pound of nitrogen per 1,000 square feet in February, and not after March 15.
• Ryegrass on Bermudagrass: stop in January. Clemson feeds an overseeded lawn through winter but stops by mid- to late January, so the ryegrass gives way to the Bermudagrass in spring. UF/IFAS says not after February in South Florida or after March in North Florida.
• Lime, if a soil test calls for it. NC State says winter is usually best, with less traffic and freezing and thawing to work it in; Penn State prefers fall and says late winter is also good.

Toward spring

Clemson mows Bermudagrass a little lower than its summer height, to about an inch, just before green-up, bagging or raking out the dead leaves from winter, and says never to burn it off. It aerates warm-season lawns only once the threat of frost has passed — see when to aerate and when to fertilize.

Common mistakes

• Taking a dormant lawn for a dead one. NC State says warm-season grass turns brown at the first heavy frost and greens up in spring.
• Nitrogen on a dormant warm-season lawn. NC State says it adds to winter injury.
• Leaving leaves on the lawn. Clemson and Illinois both clear them.
• Piling snow on one patch of lawn. Iowa State and Illinois say it invites snow mold.
• Burning off a dormant Bermudagrass lawn. Clemson says not to, for the lawn and the fire risk.

Every lawn job by zone

• Cool-Season vs Warm-Season Grass: Which Lawn Grass by Zone
• When to Fertilize Your Lawn by Zone
• When to Overseed Your Lawn by Zone
• When to Aerate Your Lawn by Zone
• When to Stop Mowing: The Last Mow of the Year by Zone
• Winter Lawn Care and Dormant Lawns, by Zone — this page
• Fall Lawn Care by Region: Fertilize, Aerate, Overseed
• Your USDA hardiness zone by ZIP code

Where there is no source here

We found no Texas source on winter lawn care that we could read. Winter injury and snow mold follow Minnesota, Iowa and Illinois; dormant warm-season lawns follow NC State, Clemson and UF/IFAS.