Homeowners often wonder whether to water their lawns after the growing season ends. Although grass may appear brown and dormant, the root system still requires moisture to survive the colder months. Deciding whether to water depends on specific environmental and climatic factors in your region. Understanding these variables is necessary to maintain a healthy lawn prepared for spring growth and prevent damage during dry, cold periods.
Why Lawns Need Water in Winter
When temperatures drop, most turfgrass enters a state of dormancy, which slows growth dramatically. Even during this resting period, the roots and the plant’s crown—the growing point—remain alive and require moisture to stay viable. This continued need for water prevents winter desiccation, which is death by severe drying rather than by freezing.
Desiccation occurs when the grass leaves lose water faster than the roots can absorb it from the soil over an extended period. Low humidity, consistent wind, and dry, sunny days can pull moisture from the turfgrass leaves, even if the air temperature is above freezing. If the soil is frozen solid, the roots cannot access any existing moisture, making the grass highly susceptible to drying out. This situation is most common in exposed areas or regions with frequent dry wind and minimal snow cover.
Snow cover typically acts as a natural insulator and a slow-release moisture source, protecting the turf from the drying effects of wind and sun. Without this protective layer, the grass is exposed to dehydration stress. Neglecting this hydration need can leave the roots dehydrated, weakening the grass and delaying its growth when spring arrives.
Even cool-season grass varieties, such as fescue and Kentucky bluegrass, remain semi-active in winter and require occasional water, unlike warm-season grasses like Bermuda, which go fully dormant. Desiccation damage often affects the leaves first, but in severe cases, it can damage the crown, which is the structure needed for spring recovery. A lawn experiencing this stress may emerge weaker and sparser.
Determining When to Water
The decision to water a dormant lawn depends entirely on local conditions and the absence of natural precipitation. Supplemental watering becomes necessary following prolonged dry spells, defined as periods of 30 to 45 days without adequate rainfall or snow accumulation. If your lawn has not received at least a quarter to a half-inch of moisture over a few weeks, the soil is likely becoming too dry.
A lack of insulating snow cover is a primary trigger for considering winter irrigation, as the bare ground allows for increased exposure to drying winds and sun. To check the moisture level, probe the soil using a long screwdriver or a soil moisture meter. If the probe meets resistance or the soil feels dry a few inches below the surface, the lawn requires hydration.
Watering should only occur when temperatures are appropriate for absorption and safety. The air temperature must be consistently above freezing, ideally above 40 degrees Fahrenheit, to prevent immediate freezing on the surface. The ground itself must not be frozen solid, as frozen soil prevents water penetration and can lead to runoff or oversaturation during thaw cycles.
Newly planted lawns or areas exposed to high wind may require water more frequently than established turf with deeper root systems. If the grass shows signs of wilt, such as folded blades or a blue-gray color, and footprints remain visible, these are visual indicators that the turf is under stress. In mild climates where grass remains semi-active, supplemental watering may be needed once or twice a month during dry periods.
Applying Water Safely
When supplemental watering is required, the application technique must be adjusted to the winter environment. The safest time of day to water is mid-morning to early afternoon, allowing maximum time for the moisture to soak into the soil before evening temperatures drop towards freezing. Watering late in the day or overnight increases the risk of water freezing on the grass blades or sidewalks.
The goal is to water deeply but infrequently, encouraging the roots to grow downward. Watering should aim to deliver about a half-inch of water, enough to moisten the root zone without saturating the soil. Overwatering is a concern in winter, as excess moisture can suffocate roots or promote fungal diseases like snow mold.
Avoid watering if a deep, hard freeze is predicted for the immediate future or if the ground is already completely frozen. Once the ground is frozen, any applied water will simply run off or sit on the surface, offering no benefit to the roots. In areas where an in-ground irrigation system is winterized, use a hose or bucket for targeted, light watering to avoid damaging the pipes.