The goal of a year-round green lawn is an elusive one. Fescue comes close but keeping it thick and healthy during the summer is tough. Bermudagrass is vibrantly green during the summer but turns buff brown in winter. Professional landscapers solve the problem by overseeding their bermuda turf with ryegrass in October. The rye sprouts readily and grows all through the winter. Next spring, theoretically, hot weather plus low mowing kills it for the summer.
The process seems simple – and it is. But there are a few ways to make the practice go better. Keep in mind that overseeding bermudagrass with ryegrass is like you trying to take a nap during a child’s birthday party. The needs of one grass might not coincide with the needs of the other.
Overseeding should be done ONLY IF your bermudagrass is in very good shape. Overseeding may retard the warm-season grass unless managed correctly in the spring, because the ryegrass competes for moisture, sunlight and nutrients. The best time to overseed is thirty days before the first frost, which usually occurs in mid-November.
MOW LOW The ryegrass will sprout more readily if it is in close contact with the soil. Before you spread seed, mow the bermudagrass lawn low (one to one and one half inches high) or run a motorized aerator over the lawn.
SEED & FEED Use 5 to 10 pounds of annual ryegrass seed per 1000 square feet of lawn. Using more seed will give you a green color sooner – but you’ll have a hard time getting rid of all that rye next summer when you want the bermudagrass to take over. At seeding, spread starter fertilizer on the lawn. Early next February, spread lawn fertilizer on the grass. This will feed the rye without unduly stimulating the bermudagrass while it is trying to remain dormant in the winter.
LOWER IN THE SPRING Ryegrass is kept mowed two to three inches tall during the winter. A few weeks before the last frost of the spring, mow the rye/bermuda down to one inch. This will shock the ryegrass while allowing the bermudagrass to begin greening up. Wait until the bermudagrass has become at least 50 percent green (usually in early May) before you begin fertilizing it with lawn food.
Overseeding with ryegrass does have drawbacks. The grass competes with the bermuda for nutrients in the spring. The fertilizer may lead to cold weather injury on the bermuda if we have a severe winter.
For more information, see Clemson University’s Overseeding with Ryegrass.