Mowing When Reseeding Existing Grass

Mowing Before Reseeding

• Late summer or early fall is the optimum time to reseed your lawn because of the cooler, but somewhat drier weeks it brings. Prepare your lawn by mowing your grass as low as possible, almost to the point of scalping it. For warm-season grasses, like Bermuda grass, it is best to do this with a reel mower. When mowing, make sure your grass is not wet and that your mower blade is sharp to ensure you are cutting the grass, instead of tearing it.

Mowing as Sprouts Grow

• After the low mowing, use a rake to remove dead grass clippings. This allows the seeds to come in contact with soil so they can germinate. Do not mow the grass until it is at least 3 inches tall, and when you do, again make sure your mower blade is sharp because the sprouts are tender. For the first few mowings, only cut off 1/2 to 1 inch of the blade since the seedlings may not recover from a more severe cutting.

Reseeding Cool-Season Grass

• Cool-season grasses, which thrive in areas where soil temperatures are between 60 and 75 degrees Fahrenheit during the growing season, almost always need periodic reseeding to improve the quality of the lawn. These lawns should be reseeded in mid-August to mid-September to give the seeds ample time to grow before the first hard frost. Use only as much seed as is recommended for your area because applying too much seed can actually reduce germination rates.

Reseeding Warm-Season Grass

• An easy way to have a year-round green lawn with warm-season grasses like Bermuda grass is to reseed with either annual or perennial ryegrass. Because ryegrass is a cool-season grass, it will thrive during the winter when warm-season grass is dormant. Ryegrass dies off in spring as temperatures rise just when warm-season grasses are starting to thrive. To ensure the cool-season grass is eliminated from your lawn, mow it short and reduce watering just as the warm-season grass starts to green up.

Considerations

• Besides mowing, two other elements greatly affect the outcome of newly seeded grass: water and food. Make sure your grass gets off to a good start by either using treated seeds or by applying a fertilizer with the seeds. Until the seeds germinate and emerge, keep the soil moist to a depth of 1/2 inch. Once the grass has established, reduce the watering frequency and water more deeply, keeping the soil moist to a level of 6 inches.