Fall Lawn Overseeding

Periodically replenish the lawn with new grass

Grass seeds
Casey Fleser/ Flickr/ CC BY 2.0

Why seed in the fall?

Fall is the best time to overseed a lawn or repair thin or bare areas. The cool nights and mild, shorter days provide the ideal conditions for seed germination. Seed is better able to retain moisture in these conditions and seedlings will thrive without the extreme heat that occurs in the summer months.

Isn’t spring best for new seed?

People are not in lawn care mode in the fall and they neglect many essential cultural practices, erroneously thinking spring is the best time to seed, fertilize, or aerate.

All it takes is one application of your standard crabgrass prevention herbicide and you can forget about spring seeding. Most pre-emergent herbicides inhibit all seed germination for up to 12 weeks. That puts you right into the middle of summer and by then it is too late to effectively overseed the lawn.

Why overseed? My lawn looks fine.

A lawn that is never overseeded tends to grow old. If it is consistently mowed, it doesn’t even have the opportunity to go to seed to propagate itself. The lawn will have to rely on rhizomes, stolons, and tillering for growth. Eventually, an old lawn will have trouble maintaining vigorous growth, competing with weeds and dealing with other lawn stresses.

Also, new varieties of grass species are entering the market every year so it is beneficial to integrate grass that may be resistant to drought, disease, or insect damage, into a lawn with older varieties without these features.

How do I overseed my lawn?

Fall overseeding can be as thorough as hiring or renting a motorized slicer seeder which sows the seed directly into the soil, or it can be as subtle as repairing bare patches in the lawn. One highly effective method is to simply apply seed directly onto the lawn immediately after core aerating , using the holes from the aerating as a seed bed.

What type of seed do I use?

Be sure to use the appropriate type of grass seed for your climate, be it cool season or warm season. Also choose the right type of seed for your lawn’s use whether it’s high use and intensely maintained or aesthetic and low maintenance. Drought resistant grasses are now available in both cool and warm season species.

I also recommend not buying the cheapest seed you can find. Grass seed comes in many varying qualities and you get what you pay for. Often the cheap seed is made up of generic, poor performing varieties of grass or worse, loaded with filler like weed seeds or annual ryegrass. You don’t have to buy the most expensive variety out there, but this is one case where you get what you pay for.