Bermuda grass is a popular warm-season turf known for its heat tolerance and rapid growth across the Southern United States and transition zones. Homeowners often consider installing new sod during the winter months when the grass is brown and inactive. Dormant Bermuda sod can technically be laid, but its long-term success depends on meticulous preparation and careful maintenance until warmer weather returns. The goal shifts from establishing immediate root growth to preserving the grass until soil temperatures are adequate for awakening.
Understanding Bermuda Grass Dormancy
Bermuda grass naturally enters dormancy as a survival mechanism against cold temperatures and frost. This process is triggered when soil temperatures consistently fall below 60°F at a four-inch depth. During dormancy, the vibrant green color fades to a tan or straw-brown as the plant stops producing chlorophyll and redirects energy into its roots and rhizomes.
The grass is not dead, but in a deep resting phase. Since the plant is inactive, the function of root growth is suspended. A newly laid piece of sod will not produce new roots to anchor itself into the soil until the ground warms up again. This biological reality changes the requirements for successful winter installation.
The Feasibility and Risks of Cold Weather Installation
Laying dormant sod is feasible and provides benefits like immediate erosion control on bare ground. The sod will remain unrooted and vulnerable until soil temperatures consistently reach 65°F in the spring. This lengthy period introduces several risks that must be managed for the sod to survive.
Desiccation
Desiccation, or severe drying out of the turf, is a major concern. Newly laid sod has a shallow root system that loses moisture quickly, especially on cold, dry, or windy winter days. Since the roots are not actively growing into the underlying soil, they cannot access deep moisture sources, making the sod prone to windburn and drying.
Frost Heave
Frost heave is another serious risk, occurring when repeated cycles of freezing and thawing lift the unanchored sod away from the soil bed. Separation creates air pockets, preventing root-to-soil contact and exposing the root system to drying conditions. Unrooted sod is also less resilient and may suffer freeze injury during extreme cold snaps, potentially leading to patches of dead grass that fail to green up in the spring.
Essential Steps for Laying Sod in Colder Months
If proceeding with winter installation, soil bed preparation is crucial. The underlying soil must be properly graded and loosened to a depth of three to four inches to ensure a level surface and maximize future root penetration. Remove debris and lightly moisten the soil just before laying the sod to facilitate the best possible contact.
Once the dormant sod is placed, immediate and firm rolling is necessary to press it against the prepared surface. This eliminates air pockets that cause drying and ensures the best thermal connection for root survival. Because the grass is not actively growing, the watering regimen changes dramatically from summer establishment.
The focus shifts to preventing the sod from drying out rather than encouraging root growth. Dormant sod requires minimal moisture, often about one inch of water every two weeks, or enough to keep the top inch or two of soil slightly damp. Avoid watering when temperatures are actively below freezing, as this can cause ice formation and potential damage to the grass crowns. Fertilization should be postponed entirely, as dormant grass cannot absorb the nutrients, leading to wasted product and potential nutrient runoff.
Ensuring Success During Spring Awakening
The success of a winter installation is measured during the spring awakening, which begins once the soil temperature stabilizes above 65°F. At this point, the grass transitions out of dormancy, and the watering schedule must be increased to encourage active root growth. This is when the sod finally begins to knit itself to the soil bed, creating a permanent anchor.
The first fertilizer application should coincide with this active green-up, ensuring nutrients are available when the plant is ready to use them. Applying fertilizer too early is ineffective and can encourage weed growth. Mowing should be delayed until the sod is sufficiently rooted, which can be tested by gently tugging on a corner to ensure it holds firmly to the ground. Once rooted, the first few cuts should be done at the highest recommended setting to avoid stressing the newly emerging leaf blades.