Even though winter is here and much of the United States is getting freezing temperatures and snow, doesn’t mean construction, especially home building stops. One of the things that homeowners appreciate (and makes homes much easier to sell) is a nice, green lawn. For that reason, contractors often lay sod in the winter so that, come spring, their houses are framed by green grass.
But, establishing turfgrass, even via sod, in most regions of the United States in the winter is risky business. Sid Mullis, with the University of Georgia Extension Service, penned a recent article in The Augusta Chronicle outlining the challenges of establishing a sod lawn in winter.
Here is what Mullis shared in The Augusta Chronicle newspaper:
My preference is for you to not plant sod during the dormant season, but much of it depends on the type of grass you are sodding and the situation. The reason it is best not to sod unless you have to is that roots in sod originate at the soil surface, where the temperatures closely mimic the air temperatures. If the air temperature is at or below freezing, roots of newly laid sod could freeze.
St. Augustine and centipede are more sensitive to freezing than zoysia and bermuda grass. There are now many zoysia varieties and some are in the same category as St. Augustine and centipede.
If you decide to sod during the dormant season (rather than during the ideal period of spring), there are management practices that can improve the chances of success.
Take a soil sample to determine lime and fertilizer needs before preparing the soil. Add lime, phosphorus, potassium and potentially sulfur (if needed to lower pH—but this is rare) and till it into the soil before sodding. Don’t apply nitrogen at this time.
It should be added in the spring once soil temperatures at the 4-inch depth are consistently 65 degrees or higher. This happens on the average about April 15 (edit note: in NE Georgia). The dormant grass’ root system is incapable of taking up nitrogen at lower temperatures.
Loosening the soil and incorporating lime and fertilizer by tilling to a minimum depth of 3 to 4 inches is typically adequate for turfgrass establishment. Tilling deeper is even better.
After thorough tilling and mixing, the soil should be leveled, smoothed and moistened. Large rocks, stones, weeds and other debris should be removed. The soil should be lightly watered but not saturated. Ruts from foot traffic or equipment can occur when soils are excessively wet and are difficult to repair after the sod is laid.
To prevent drying, potential cold injury and death of roots, sod should be installed within 24 to 48 hours after harvest. Turfgrass sod does not have a long shelf life in the best of conditions.
If freezing temperatures are predicted while sod is on the pallet, the exposed roots could die. Getting the grass off the pallet as soon as possible also takes advantage of the soil’s radiant heat. Higher soil temperatures may offer protection from cold injury compared to temperatures on the pallet.
Sod should be laid tight and rolled to ensure sod-to-soil contact.
Water management is critical when laying dormant sod. Although the root system is not highly active or developed, water is needed to keep the upper 1 to 2 inches of soil moist. During the winter, rainfall may suffice, but about 0.25 inches of water may be necessary each week.
After sodding, frequently and gently pull up sod edges to make sure the soil is moist. The survival of off-season transplanted sod is dependent on avoiding desiccation, or drying. Those lovely winter days, with temperatures in the upper 60s or low 70s, little humidity, sunny skies and gentle breezes are ideal conditions for desiccation. In as little as a day, turfgrass can dry out and die.
Low-temperature injury can be a problem because the crowns, stolons and shallow rhizomes of the turf might be frozen and killed. The result is the grass dies while dormant and is not noticed until green-up in spring. This also helps explain why lawns that were sodded the previous spring or summer are dead the next spring.
Desiccation and cold injury might be reduced by topdressing the dormant sod. Topdressing can also smooth shallow depressions and fill seams, conserve moisture and potentially retain heat.
Successful transplanting is dependent on a healthy sod. St. Augustine will usually have a lot of green during the winter, but the other three grasses are typically brown. Examine the sod closely when buying it to insure the sod is just dormant, not dead.
Winter annual weeds can be common for dormant sodded grasses but I wouldn’t use pre- or post-emergence herbicides initially because they could cause permanent damage. Just pull any weeds. Herbicides can be used once the grass has fully rooted down well in the spring.