Sod does not typically die during the winter months. Instead, it enters a natural, protective state known as dormancy, a survival mechanism against cold temperatures and environmental stress. The appearance of brown or yellow turf is a sign of this biological slowdown, not death. Understanding this process ensures your sod remains healthy and ready to green up when warmer weather returns.
The Biology of Winter Dormancy
Dormancy is the grass plant’s way of conserving energy when conditions are unfavorable for active growth, typically when temperatures drop below 40 degrees Fahrenheit. Metabolic processes slow significantly, redirecting resources away from the visible blades and toward the protected root system. This strategy protects the crown of the grass, which is the base of the plant where new growth originates.
The brown color develops because the grass blades cease chlorophyll production and dry out above ground. However, the underground root structure remains alive and functional, albeit at a much slower rate. This temporary “hibernation” allows the sod to withstand freezing temperatures and dry winter winds. Stored energy in the roots will fuel the rapid green-up once spring arrives.
Essential Preparation Before Winter Sets In
Preparing sod in the late fall is the most important step for maximizing winter survival and ensuring a strong spring return. This involves a final mow where the height is gradually reduced to about 2 to 2.5 inches for most cool-season grasses. This shorter height minimizes the risk of snow mold, a fungal disease that can develop under snow cover. Avoid “scalping” or cutting the grass too short, as this stresses the plant just before dormancy.
A late-fall fertilization, often called a “winterizer,” is highly beneficial. This fertilizer is typically high in potassium, which supports strong, hardy root systems and enhances the plant’s resistance to cold and environmental stress. Applying this slow-release nutrient source four to six weeks before the first hard frost allows the sod to absorb and store energy for the winter.
Adequate hydration before the ground freezes solid is necessary, particularly for sod laid less than six months prior. The sod needs enough moisture to prevent desiccation (extreme drying) during the winter, which can damage the shallow root system of newly installed turf. Watering until the ground freezes ensures the roots have a moisture reserve.
Maintaining Sod During Cold Weather
Once the sod is fully dormant and the ground is consistently cold or frozen, the focus shifts to protection rather than active care. Reducing foot traffic on the dormant grass is necessary. When grass blades are frozen or brittle, walking on them can damage the individual blades and the delicate crown of the plant, leading to brown spots or bare patches that last until spring.
Snowfall is helpful for dormant sod, acting as a natural insulating blanket. This layer of snow helps moderate the soil temperature, protecting the roots from extreme temperature fluctuations and dry winter winds. However, if the ground is not entirely frozen and the area experiences an extended dry, sunny period, a light supplemental watering may be needed to prevent desiccation, especially for recently laid sod.
What to Expect When Spring Arrives
When temperatures begin to rise and the days lengthen, the sod naturally breaks dormancy and resumes active growth. The first sign of recovery is a gradual green-up as the grass begins to produce chlorophyll again. This process requires patience, as the full return to a lush green color can take several weeks.
To aid this transition, a spring cleanup is helpful, including lightly raking matted-down areas to allow for better air circulation and sunlight penetration. Applying a balanced, slow-release fertilizer provides the necessary nutrients for new growth. Any small, patchy areas that do not green up may indicate winter damage from desiccation or excessive traffic and can be addressed with minor repairs or reseeding.