Winter is commonly thought of as a time of rest for many plants. Deciduous plants lose their leaves, and blades of certain turfgrass lawns experience die-back as the turfgrass goes dormant. Whether or not a turfgrass experiences dormancy depends on the species and where in the state they are grown.
Warm-season grasses such as St. Augustinegrass, zoysiagrass, centipedegrass, bermudagrass, and bahiagrass are prone to winter dormancy. The phenomenon commonly begins in November in the Midlands and Upstate, where frequent frosts occur. Turfgrass dormancy less frequently occurs on the coast, where air temperatures do not dip as low as elsewhere in South Carolina. Winter dormancy does not mean that the turfgrass is dying, and if maintained correctly, new blades will emerge in spring. The turf is alive underground. Roots are still taking up water and nutrients for daily metabolic activity as well as for storage until spring when they will be used for new growth. This activity is much slower in winter than during the growing season. If there is no water present in the soil, the turfgrass becomes water-stressed, and in extreme cases, patches may die.
Cool-season grasses, such as fescues and ryegrass, are actively growing during the winter months. Simple tests, such as the color test, footprinting, and leaf check, are great cues to recognize when the turfgrass needs irrigation. See HGIC 1207, Watering Lawns for more information on how to perform these tests and what they mean.
The bottom line is that in most years, South Carolina receives enough rainfall to meet warm and cool-season turfgrass demands during the winter. For warm-season grasses, apply 1-inch of water if no rainfall has occurred within 3-weeks. Irrigate in the morning once the frost is gone and the grass is dry. However, use the tests previously mentioned to determine if cool-season grasses need to be irrigated. Refer to HGIC 1803, Landscape Irrigation Management Part 4: Winter Irrigation & Winterizing factsheet for more information on winterizing irrigation systems and specific turfgrass maintenance calendars on the HGIC website for irrigation information for specific turfgrasses.