We should all know by now that it's better to change over traditional lawns to eco lawns or other ground cover. But the reality is, most people refuse to break up with their lawns. If you are currently nursing along a fescue monoculture in your front or back yard, or want to create one, I still think it’s a bad idea—but that said, the time to implement your bad idea is now. The warm weather, combined with the rain many are experiencing, creates the perfect environment for germinating grass seed. 

"Overseeding" vs. "reseeding"

"Overseeding" means applying new seed to an existing lawn. While this does require and benefit from some prep work to the ground under the grass, you generally leave the existing lawn alone and just top-dress it. "Reseeding" means starting over. You remove the existing grass (a pain the proverbial ass if there ever was one), re-prep the ground and then plant new grass seed. 

Why people overseed

Late summer/early fall is precisely when you want to prep your space and get lawn seed planted to reseed or overseed—and you should consider why you’re choosing one direction over another. Patchy grass can be resolved by overseeding. If the lawn feels thin, or you can still see the dirt below the lawn, overseeding can beef up the turf by increasing density. That density of new grass will improve the overall “green-ness” of the space. An even better reason to overseed is to introduce new, superior strains of fescue, or diversify the strain. 

Why people reseed

People generally start over when the ground has become uneven, full of weeds, has become terribly thatched, or has a lot of roots growing through. The other main reason people reseed is to put in irrigation below the lawn. In these cases, it makes sense to tear everything up and address the ground under the grass itself. Grass sucks the nutrients out of the ground and compacts it, so once the grass is gone, you’ll want to aerate the ground and add compost and other nutrients back into it. Tear out roots, then level the ground well and then reseed. 

How to overseed or reseed

In order to germinate, grass seed needs to touch a growing medium, which means soil or compost. To achieve that on an existing lawn you’re either going to have to rake the grass enough to scarify the ground so that there is dirt for the grass seed, or you can top-dress the existing lawn with some compost. Compost isn’t a bad idea because the ground and lawn itself almost certainly need it. Now you can add your grass seed. 

To reseed, you need to take additional steps. Removing the lawn itself will also remove a few inches of depth from the lawn, so when you replace it with more dirt or compost, you’ll have a nice level ground. 

When I’ve reseeded, I’ve taken the additional steps of using a rototiller to aerate the ground below the lawn. This ameliorates the compaction likely incurred from the grass growing. Next, I sheet mulch with cardboard, to smother the remaining seeds in the ground. I then layer compost on top of the cardboard, level it out, and then add the grass seed. 

Protect and cultivate your seeds

Lawn mulch has, in my experience, ensured success, whether you're overseeding or reseeding. This is a specific type of mulch that sits on top of the lawn and helps ensure some moisture as the seed is germinating, but also obscures and protects the seed from birds and other animals. 

During the first few weeks, you’ll need to ensure the seeds are always moist, which means watering as many times a day as necessary. Remember, if the ground is moist, the seeds will absorb moisture from the ground, so long as they are touching.

Wait to mow

You might not get a chance to flex your mowing muscles before winter sets in this year, and that's totally fine. You want to ensure you're not cutting the lawn before it can stand it—the lawnmower itself, and you walking on the lawn, can both cause damage. Only mow if the lawn is planted early enough to reach five to six inches tall before winter sets in.