By Sharon Omahen
University of Georgia
"If the air is at or below freezing," he said, "there's a risk that the roots of newly laid sod will freeze."
Despite the risks, laying dormant warm-season sod is common. If you plan to lay Bermuda, centipede, St. Augustine or zoysia sod, Waltz recommends a series of practices that improve your chances of success.
First stepThe first step is to properly prepare your site and take a soil sample.
"Root-zone preparation is critical," Waltz said. A soil test of the site just before you lay the sod will show the soil pH and nutrient needs.
Don't add nitrogen. "Soluble nitrogen is mobile in the soil, so the root system can't acquire it," he said. Add nitrogen in the spring once soil temperature at 4 inches deep is consistently 65 degrees or higher.
Once you know which nutrients your soil needs, loosen the soil and add the nutrients by tilling them into the top 3 to 4 inches. Remove any large rocks, stones, weeds and other debris. After you thoroughly till and mix the soil, level and smooth it.
Before you lay the sod, Waltz said, lightly water the soil. Don't saturate it. If the soil's too wet, the site can get ruts from foot traffic or equipment that can be harder to repair after you lay the sod.
Ship fast, plant fastTo keep cold injury or drying from killing the roots, lay the sod within 48 hours after it's harvested. Turfgrass sod doesn't have a long shelf life in the best conditions, Waltz said. If temperatures drop below freezing while the sod is still on the pallet, exposed roots could freeze and die.
Lay the sod tight to the ground and roll it to ensure sod-to-soil contact. Even when you lay it under perfect conditions at ideal times, water management is critical. This is true for dormant-season sodding, too.
"Although the root system of dormant grass isn't highly active or developed," Waltz said, "it still needs water to keep the growing points of the plant hydrated." You don't have to water as much, though. A dormant plant doesn't need as much water as actively growing grass.
As soon as the sod is laid and rolled, water it lightly. Green sod needs many light waterings every day, but dormant sod needs only enough to keep the top 1 to 2 inches of soil moist.
"During the winter and spring, rainfall may suffice," Waltz said. "But if irrigation is needed, about an inch of water may be necessary every two weeks."
Water is keyKeep the soil moist. In as little as a day, undeveloped roots can dry out and die.
Don't let balmy spring weather lull you into a false sense of security. "It's easy to enjoy cloudless days in the low 70s when there's little humidity and a comfortable breeze blowing," Waltz said. "But these are ideal conditions for plant desiccation and sod loss. In this weather, water is rapidly lost from the soil and plants into the atmosphere."
Direct cold injury can freeze and kill crowns, stolons and shallow rhizomes, Waltz said. Unfortunately, newly sodded turfgrass lacks the deep rhizomes and expansive roots necessary to recover from these winter stresses.
"Successful sod transplanting depends on proper soil preparation, good soil-to-sod contact and, most important, proper water management to prevent desiccation," Waltz said.
(Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)