Seeding / Slit Seeding

What is overseeding?

Overseeding is the planting of grass seed directly in to existing turf without tearing up the turf, or the soil. It is an easy way to fill in bare spots, improve the density of the turf, establish improved grass varieties and enhance your lawns color. If a lawn looks old, worn out, needs growing amounts of water and fertilizer to thrive, or is insect prone, it’s a perfect candidate for overseeding.

The benefits of overseeding

Many older lawns were established with common type turf grasses not suited for the needs of today’s homeowner. They’re often more disease and insect prone, requiring more fertilizer and water. Overseeding newer turf grass varieties into an older lawn can help it better withstand insects; disease, drought, shady conditions and heavy traffic. The investment in overseeding pays off by reducing the amount of fertilizer, water and pesticides required. Most importantly, a renovated lawn stays greener and looks thicker and healthier!

Before you overseed

For various reasons, old turf sometimes deteriorates dramatically or dies out completely. Overseeding with an improved grass seed mixture can get new turf growing in bare areas as well as “sprucing up” areas where the turf is thin and unhealthy looking. First, however, you must analyze the problems that caused the original turf to deteriorate. It might be due to conditions that, if not corrected, will eventually cause the overseeded lawn to deteriorate, too.

Correctable problems include:

If you have trouble identifying the problem, ask your local lawn professionals or your county extension office. The main thing is to correct the problem before you establish new grass.

Aeration can prepare soil for overseeding

Although not always mandatory, “core aeration” can be a beneficial first step in preparing worn-out turf for overseeding.

Proper aeration:

Overseeding Methods

Slit-seeding with a mechanical slit-seeder is the best method for overseeding established turf. Slit-seeders usually have vertical cutting blades that cut through the thatch layer and open up a slit or miniature furrow 1/4-inch into the soil. The slit-seeding unit should have concave disk blades that follow in the slits and keep them open while the seed is dropped; it ensures the seed gets into the soil where it can germinate. Slit-seeding generally takes less seed than broadcast seeding, because most of the seed gets into the soil so it can germinate. More seed-to-soil contact means a higher germination rate and a better strand of new grass.

We recommend making two passes with the overseeder, seeding at 50% of the recommended rate. The two passes are at a 45° angle to each other, leaving a diamond – shaped pattern. This method is fast, and results in the seed being placed a maximum of 2 inches apart.