Photo found on Flickr, courtesy of PhotoFarmer.
Overseeding involves planting an annual cool season grass in the fall on top of a permanent warm-season grass. It’s a popular solution to a major drawback of warm-season grasses, which is that they go dormant after the first frost and stay brown until spring.
Overseeding with ryegrass is a common practice where homeowners and turf managers want to enjoy green lawns year round. It also helps prevent erosion on new lawns where the permanent grass is not yet established.
Both annual and perennial ryegrass are used for overseeding. With darker green, finer leaves, perennial ryegrass is considered more attractive. Both annual and perennial ryegrass die out in the spring in warm climates, but the perennial can interfere with permanent lawns because it lives longer in the spring. Perennial ryegrass is more disease-resistant than annual ryegrass.
When to Overseed with Ryegrass
The best time to overseed is when the days are warm enough (around 70 degrees F) to encourage germination and growth and the nights are cool enough (around 50 degrees F) to discourage diseases. Thirty days before frost is typically a good time, but timing varies by location.
Preparing the Lawn for Overseeding
It is important to dethatch a heavily thatched lawn; otherwise the ryegrass seed will not make contact with the ground, leaving unseeded patches of lawn. Dethatch by verticutting or aerifying. If aeration is done, wait 30 days before overseeding. Verticutting should be done just before overseeding.
Mow the lawn closely and catch or rake clippings before seeding.
How to Sow Ryegrass
If using annual ryegrass sow 10 pounds of seed per 1,000 square feet. Sow perennial ryegrass at a rate of 5 to 15 pounds per 1,000 square feet. (The type of permanent grass affects sowing rate, with Bermuda grass requiring a higher rate.)
To ensure even distribution sow half the seed in one direction and the other half at right angles to the first half. After sowing rake the ground with a broom to help the seed make contact with the soil.
Until the seeds germinate water lightly two or three times a day. Then water only enough to prevent wilting. Overwatering encourages diseases.
Maintaining the Winter Lawn
Mow when the lawn is about 1 to 2 inches high. After that mow to 1 to 1 ½ inches when the grass reaches 2 to 2 ½ inches high. Keep mower blades sharp to avoid ripping the blades of the ryegrass.
After the second mowing apply ½ pound of nitrogen fertilizer per 1,000 square feet.
Reestablishing the Permanent Lawn
In warm climates ryegrass usually dies out in late spring. However, it can live longer if the spring is cool, creating competition for the permanent lawn, especially in times of drought. Stop fertilizing in March to discourage the ryegrass from growing.
Mow the ryegrass as close as possible, lowering the mower height with each mowing. Resume regular warm season mowing, watering, and fertilizing when the permanent grass starts growing.
Want to Learn More About Overseeding Your Lawn with Ryegrass?
The wisdom and timing of overseeding with ryegrass varies by location. Local extension offices can advise homeowners on best practices for their areas. To find the closest extension office, go to: The National Institute of Food and Agriculture website.
Check out the following sites for more information about overseeding with ryegrass:
Overseeding with Ryegrass. Clemson Cooperative Extension.
Here’s a great .pdf file about Overseeing Bermudagrass with Perennial Ryegrass from The University of Tennessee Extension.
Ryegrass. Landscape America.