If you want a green lawn in winter, you have two choices. The first is to have a tall fescue lawn. That can be a challenge in summer considering the extreme heat and drought we have faced in August and September.
The second option is to overseed with a temporary grass. Both annual and perennial ryegrass are fine for this. Each has its merits. In either case, we are fast approaching planting time.
Annual ryegrass establishes faster and the seed is cheaper. It’s also easier to transition back to the summer grass when the time comes. The disadvantages to annual ryegrass are that it grows faster and more upright. It also is a coarser texture. During an extremely cold winter, it often shows freeze damage and develops a whitish cast.
Perennial ryegrass is far more attractive in lawns and athletic fields. The texture is finer and the color is usually a darker green. Also, it can be mowed at a lower cutting height without looking stemmy. In this region, perennial ryegrass is totally winter hardy and should not show signs of cold damage.
Seedling establishment is slower than for annual rye, but it’s still better than any other option. Perennial ryegrass doesn’t transition back to a warm-season grass like bermudagrass quite as easily since the growth habit is lower.
In either case, returning to the summer grass usually involves letting the winter turf get a little long when the summer species first begin to break dormancy. Scalping the turf will stress the ryegrass and the bermudagrass will take over. If warm weather follows the scalping process, the transition will be rapid.
Some people choose to spray the ryegrass right before the Bermudagrass breaks dormancy, but I don’t recommend it. The mowing method works well, and it’s safer for the turf. Leave the spraying to the professionals.
The best time to overseed is when day temperatures are warm but not hot and night temperatures are around 50F. Soil temperatures are usually ideal in the fall, and with a little water the grass will really take off.
If the turf contains abundant thatch it’s usually beneficial to mow closely, dethatch and possibly aerate the turf before overseeding. Also, athletic turfs are often overseeded several times and the process is started earlier in the fall. Whenever major disruption of turf is required, it’s best if the grass is in ideal growing conditions.
On home lawns, many folks are often discouraged when they overseed. Surprising as it may sound, the rate for overseeding often exceeds the rate for seeding a new lawn. When seeding lawns later in the fall, preparation of the existing summer turf is usually less. Bermudagrass can be damaged when disturbed too much later in the fall.
Both annual and perennial ryegrasses are bunch type grasses. They don’t spread by creeping above ground or underground stems. Therefore, they must be seeded thick or the resulting turf will be patchy and clumpy. When bunch type grasses are included in any lawn, they should comprise the major share of the grass plants. The same is true for tall fescue.
Keeping your lawn green in winter is a little extra work and expense. Some think it’s worth it. Some don’t.
Ted Manzer teaches agriculture at Northeastern High School.