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By Dave Han, Ph.D., Auburn University
Al ab ama Tu rf Tim e s > >> Fa ll 2 012
The
best time to start preparing warm-season grasses for the next winter is actually the minute greenup starts in the spring. A healthy, deep-rooted and stress-free grass withstands cold temperature and drought stress while it’s dormant much better than thin, weak, stressed turf, and building a healthy turfgrass is something that happens throughout the entire growing season. Yet, it is during the late summer and fall that most people’s minds turn to “winterizing” their turf, or preparing it for the upcoming cold weather. It is not just cold weather, however, that can cause problems during the winter months. Cold, dry winds can lead to turf drying out. Traffic on dormant turf can be overdone. Herbicide use on
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“dormant” turf can injure the grass because grass is often not completely dormant in Alabama, even though it may appear to be at first glance. With that in mind, here are some ways to prepare turf for the winter months.
Fertilization
I used to recommend not applying nitrogen to warm-season turf in the fall, especially after September. Now, however, research shows that bermudagrass fertilized with small amounts of N in late fall retains color better, greens up earlier in the spring and does not have increased susceptibility to winterkill. The emphasis here is on small amounts of N. Applying one half pound of N per 1,000 square feet per month in September and October is enough to get
the benefits. It is still a bad idea to fertilize with large amounts of N in the fall, and I still don’t recommend fall fertilization of zoysiagrass, especially in wet fall weather, because of the increase in large patch disease pressure that this causes. For many years, researchers have studied the relationship between potassium fertilization and winter survival in turfgrass. The bulk of this research, though, has been done with cool-season grasses, especially bentgrass, bluegrass and ryegrass. As strange as it seems to Southerners, the cool-season grasses do suffer from winterkill in cold climates. The research definitely shows that grasses deficient in potassium have worse cold tolerance than grasses with sufficient levels of K. Of the warm-season