For those of us lucky enough to live in the southern portion of the United States where year-round grass growing is possible, you may have noticed the little problem that warm-season grass species have during the cooler winter months; the dreaded winter time dormancy. Dingy brown begins to replace lush green, and is a natural result of a warm-season grass going dormant. Unlike cool-season grasses like Kentucky bluegrass, warm-season grasses are most vigorous during the hot, summer months. This is perfect for southern climates where the warm months outnumber the cooler ones, but can be disappointing for those of us that enjoy a year-round green lawn. Bermudagrass, one of the most popular warm-season grasses, is very susceptible to winter time dormancy. So what can be done about this issue? Should we just throw in the towel and accept defeat, or is there a way around the winter time blues (or browns in this situation)? 

The Benefits of Overseeding

One way to overcome winter time dormancy issues with bermudagrass is through the practice of overseeding. Overseeding involves sowing grass seed over an already established lawn, and is actually one of the most overlooked lawn care practices by homeowners. There could be many reasons for overseeding, such as repairing bare or thin spots in lawn or rejuvenating an older lawn. In this case, overseeding bermudagrass with a cool-season grass species is a clever way of ensuring year-round greenness. 

Overseeding Bermudagrass with a Cool-Season Grass

It works like this: A bermudagrass lawn is overseeded with a cool-season grass around September or October. As autumn approaches, the bermudagrass begins to go dormant while the freshly sown cool-season grass begins to germinate. By the arrival of winter, the cool-season grass has grown in and thrives in the cooler weather, hiding the dormant bermudagrass and providing a lush green look. By the arrival of spring, the cool-season grass has served its purpose and begins to die off as temperatures heat up and the bermudagrass begins its transition back out of dormancy. Finally, as summer returns the bermudagrass has reclaimed full control of the lawn and you have just achieved a year-round green lawn. 

What Type of Cool-Season Grass Works Best?

As to what type of cool-season grass to overseed you bermudagrass lawn with, there are a couple choices. The key is to choose one that won’t last too long into summer so as to avoid competing with your bermudagrass. The most popular choice is ryegrass, either annual or perennial. Annual ryegrass works well due to its intolerance of hot weather, ensuring that come springtime the bermudagrass won’t be wasting energy or resources competing with the annual ryegrass. Annual ryegrass is cheap and germinates quickly, although it has a tendency to be wet (contributing to increased grass stains on clothing) and hard to mow. On the other hand, perennial ryegrass is typically preferred by professional groundskeepers because of its superior dark green color, slower growth, and finer leaf texture. Another choice is creeping bentgrass although it’s seldom used due to its high costs and availability. It’s important to note that bermudagrass should not be overseeded with tall fescue or Kentucky bluegrass since these grasses will last well into the summer and will compete too much with your bermudagrass. 

Tips for Overseeding

To achieve maximum benefits from overseeding your bermudagrass lawn with ryegrass, wait until soil temperature drops to around 70 degrees. For folks living in the upper south, this usually falls around September 15th. For the lower south, October 15th is the usual time. During this interval it’s important to mow your bermudagrass quite a bit lower than normal to ensure the ryegrass seed will make good contact with the soil. Perennial ryegrass should be seeded at 12-15 lbs. of seed per thousand square feet, and is the same rate for annual ryegrass. After sowing the seed it will be necessary to water the lawn frequently (twice a day for the first three days) for about ten minutes at a time. The soil should be kept moist but not soaked. Usually the new ryegrass will sprout within a week or two. Remember that ryegrass requires more water than bermudagrass, and a new watering schedule will need to be implemented. 

By using this overseeding method it’s possible to achieve a constantly green bermudagrass lawn anytime of the year.