The Grounds Guys
Grass seeding machine

What Is Overseeding and Slit Seeding?

If your lawn looks like a patchwork quilt with some bare spots disrupting its uniform look, you may not need to tear everything out and start over by completely re-seeding it. There’s a simpler fix to restore your yard to its lush beauty -- overseeding. It’s the same lawn seeding technique used by landscapers to sow cool-season grass seeds on top of warm-season turfgrasses to achieve a green lawn during the winter.

How to Overseed a Lawn" video!

The Grounds Guys can offer tips to make this process a success in your yard with a simple 1-2-3 method:

  1. First, identify the reason(s) you have for overseeding your lawn

  2. Next, prep your yard using our helpful steps before starting your lawn seeding project.

  3. Finally, consider slit seeding by using the machine and method below.

Reasons for Overseeding

  • To renovate a bare, patchy lawn. By leaving the existing grass in place, lawn seeding can fill in the gaps by sowing seeds only where new grass is needed.

  • To thicken up a sparse lawn. You can overseed your entire yard to transform a wispy lawn to a thick carpet of grass.

  • To crowd out weeds by adding new grass. Thick, healthy grass can out-perform weeds by pulling water and nutrients away from them.

  • To change your existing turfgrass to an improved variety. You may not be able to change to a different type of grass by overseeding, but you can transition to a new, improved variety of the same type grass.

Hand planting grass seed for overseeding green lawn care

Prep Your Lawn

  • Have a soil test done. You want to make sure your grass receives the proper nutrients for optimal growth, so don’t broadcast fertilizer randomly or you may do more harm than good. Excessive fertilization can burn grass roots, and it can also stress the grass, which makes it susceptible to disease.

  • Decide on the type of grass seed you want. If you’re unsure of the best choice for your yard, The Grounds Guys can recommend something for you. Remove all weeds. After using chemical herbicides, wait two weeks before lawn seeding.

  • Mow your lawn. Without scalping it, mow it down to about 1 inch so the new grass seeds can germinate better. Typically, you'll mow your lawn a little higher than this, but before lawn seeding, you'll want to adjust your mower blades to a slightly lower setting.

  • Rake the lawn (particularly if you don’t have a bagger on your mower). Remove all grass clippings, leaves and other debris that could cause the new seeds to have spotty germination.

  • Apply fertilizer based on soil-test-recommendations. Be sure to water the fertilizer in well after you apply it.

Slit Seeding

A slit seeder is a handy lawn machine that opens small grooves, or slits, in the ground that receive grass seeds. Follow these tips for using this machine like the professionals:

  • Choose a machine that deposits grass seed only after it makes slits in the turf (not before).

  • Make sure you adjust the seed broadcast setting according to the manufacturer's recommendation for specific seed type.

  • Apply half the grass seeds in one direction -- in parallel rows as you do when mowing the lawn -- and the other half in parallel rows perpendicular to the first series of rows.

  • Water the lawn after you use a slit seeder, and keep it moist until the seeds germinate. This may mean watering the lawn every day for a couple of weeks.

Slit seeding machine being used on a lawn

If you hit a snag and have questions about lawn seeding or using a slit seeder, call on The Grounds Guys. We can help walk you through any uncertainties so you’re overseeding with skill and confidence! Got mosquitoes? We know professionals who can help with those, too.

Did you know? The Grounds Guys is a Neighborly brand. Discover an entire network of professionals to assist with any of your home service needs at