For most of us, the fall is the time of year for college football (GO DAWGS!), cool, crisp air in the mountains and raking leaves that seem to get everywhere. It is also a time of year when many people consider overseeding their warm season lawns to produce a green carpet of grass all year long.
Throughout the years, annual ryegrass has been used to overseed a lawn, but lately the trend has moved to perennial ryegrass. Ryegrass generally has better turf qualities, handles insects and diseases efficiently and is easier to manage.
For the home gardener, use about 5 to 10 pounds per 1,000 square feet to achieve a successful wintertime lawn. But look for the “certified” blue tag seed that is free of annual bluegrass. It may be a little more expensive, but it will save you time and money in the long run.
If you go with the higher seeding rate, obviously you will have a quicker grow in the fall, but it may create more problems in the spring. Opting for the lower-end rate will make a thin lawn early, but it comes in well later.
The big question that comes to mind is when to overseed. Here are a few clues:
Soil temperatures at a 4-inch depth should be approaching 75 degrees.
When night temperatures are consistently in the 50s and the daytime temperature at midday is below 70 degrees.
If you go strictly by the calendar, overseed about 2-4 weeks prior the average annual first killing frost date. Visit www.georgiaweather.net for the information.
Overseeding success depends on good soil-seed contact.
Seedbed preparation requires close mowing with some light vertical mowing and removing as much of the loose plant debris from the surface. The better job you do at this, more of the overseeding will take. But it will also mean a harder time for your warm-season grass to transition from dormancy in the spring. It becomes a fine balance based on what you want from your lawn.
Just like any other type of planting, watering the seed is critical. In the beginning water lightly but frequently to ensure good soil moisture, allowing the seed to germinate. This may mean a couple of times to watering in a day. Even though you may be watering frequently in the beginning, the total amount of water applied usually will be less than a half an inch. Once you see the grass emerge, reduce the number of watering time, but increase the duration until you have an inch or so of water.
Mow and fertilize the lawn about three weeks after germination. Mow the new stand of grass when it is about a third higher than you want it.
Next, fertilize once you know you have a good stand established so the warm-season grass underneath is less likely to compete. As a good rule of thumb, apply no more than 1 pound of nitrogen per 1,000 square feet at a time. If a fertilizer is 34 percent nitrogen, apply roughly 3 pounds per 1,000 square feet to get 1 pound of nitrogen over the lawn.
A successful, year-round lawn is all about the details and understanding that more often than not things are done based on weather patterns and temperatures rather than the calendar.
Michael Wheeler is county extension coordinator for the UGA Cooperative Extension office in Hall County. You can contact him at 770-535-8293, www.hallcounty.org/extension. His column appears weekly and on gainesvilletimes.com/life.