Most Bermuda grasses will go dormant (turn brown) during winter months. The most common seed variety used to overseed Bermuda, a warm season grass, is ryegrass, which is a cool season grass. Perennial ryegrass is dark green, does excellent in full sun, tolerates high traffic well, is stress and pest tolerant, and germinates quickly.
October is a great month to overseed as the Bermuda is slowing its growth rate but the weather is typically still warm enough for the ryegrass seed to germinate.
Daytime temperatures should not be above 70 degrees and nighttime temperatures should not reach above 50 degrees. This usually falls two to four weeks before the first frost of winter. You can also tell it may be time to overseed when your lawn is starting to thin but is still in good condition.
Continue to maintain your sod lawn throughout the winter with proper water, mowing, and fertilization.
It is important to correctly manage your lawn in the spring when Bermuda (warm season) grass is coming out of dormancy. The ryegrass (cool season grass) can compete for moisture, sunlight, and nutrients. It is important to stop fertilizing in early spring but to continue once the Bermuda has established itself again. Maintaining a proper low mowing height as the Bermuda grass re-establishes will stress the ryegrass, or cool-season turf, aiding in the Bermuda grass growth.
Maintaining your sod lawn throughout the year, especially during overseeding in the fall and the establishment of your warm season grass in the spring, is vital to the overall health of your lawn. Disease and inability of the Bermuda grass to establish without struggle will be more likely if there is not proper maintenance year round. With a little time and effort, it is possible to transition smoothly from warm season Bermuda grasses to cool season ryegrasses and have a green lawn year round.