Pros and cons of overseeding your lawn 09-22-08

Fall has arrived. In a few more weeks a heavy frost will put warm season turf species lawns into winter dormancy. To some homeowners, the thought of a brown lawn just shouldn’t be so, and they look for ways to keep it green all winter. The most logical solution is to overseed with a cool season turf species such as ryegrass. In making a decision to overseed your lawn, or not, some consideration should be made on what the advantages and disadvantages of doing so are.

The most important one is asking will the overseeding be detrimental or beneficial to the permanent lawn? Overseeding your warm season lawn with cool season grasses can actually delay next spring’s green-up of the permanent lawn and may even weaken it. Just keep in mind that cool season turf species thrive at temperatures in the 60-70 degree range, so next spring when your permanent lawn begins to break dormancy, the over seeded turf species will be very competitive and act similar to any other weeds competing for nutrients, water, and space. On the plus side, the temporary lawn could prevent erosion problems, prevent mud tracking into the home, and would provide the aesthetics of a beautiful green lawn all winter.

The turf species of preference for winter overseeding warm season lawns should be perennial ryegrass. Perennial ryegrasses are much finer textured than annual ryegrass cultivars. They generally have much better color throughout the winter, aren't as prone to clumpiness, and don't produce as many unsightly seed stalks in the spring.

Seeding rate for home lawns with perennial ryegrass should be 8-10 pounds per thousand square feet and if you use annual ryegrass increase this by another two pounds. Seeding should be done when soil temperatures reach around 70 degrees which, as a general rule, will occur around the middle of October for much of Mississippi.

Cultural practices of mowing, fertilizing, watering, and pest management must be continued throughout the winter for an overseeded lawn. Once the permanent lawn does begin spring transition the temporary lawn should be removed either mechanically or chemically. There are labeled herbicides available now that are very effective in removing cool season turf species from warm season permanent lawns, so you may want to consider using one of these in the spring to remove the ryegrass once the permanent lawn begins spring growth.

Published September 22, 2008

Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. wwells@ext.msstate.edu