What It Means
Overseeding is sowing grass seed into a lawn that's already growing, instead of starting over from bare soil. In the North it's how a thin cool-season lawn gets thicker, and University of Minnesota Extension puts the best window at mid-August to mid-September. Southern lawns are a different storyUser storyA short description of something a product should do, written from the point of view of the person who needs it, often in the form "As a, I want, so that." See more: there it usually means sowing ryegrass into a warm-season lawn so it has even turf through the winter, and Clemson Extension limits that to bermudagrass.
Try It: Three Questions on Overseeding Timing
Pick an answer for each. Answers come from University of Minnesota Extension and Clemson HGIC.
1. Best window to overseed a cool-season lawn in Minnesota?
Right. That's UMN's preferred window.
Not quite. UMN prefers mid-August to mid-September.
2. Which southern lawn does Clemson say to overseed with ryegrass?
Right. Only bermudagrass.
Not quite. Overseeding damages that grass. Only bermudagrass.
3. After core aeration, how long before overseeding bermudagrass with ryegrass?
Right. The holes need time to heal.
Not quite. Clemson says 30 days.
of 3
How It Sounds at Home
- "The back lawn is so thin, let's overseed it in August."
- "We overseed the bermuda with rye so it stays green over winter."
- "Mow it short first so the seed actually hits dirt."
The Breakdown
When to overseed
| Lawn | When | Source |
|---|---|---|
| Cool-season, in Minnesota | Mid-August to mid-September | UMN Extension |
| Bermudagrass, adding ryegrass for winter | Fall, about 30 days before the first frost, with days near 70°F and nights usually above 50°F | Clemson HGIC |
| Bermudagrass just core aerated | Wait 30 days before overseeding | Clemson HGIC |
| Centipede, zoysia, St. Augustine | Skip ryegrass overseeding | Clemson HGIC |
How often. Buhata's own suggestion: overseed a cool-season lawn in the late-summer window whenever it has gone thin. No source we checked sets a yearly count. Ryegrass on bermudagrass is a choice you make each fall; Clemson's own article asks whether you should overseed at all.
Make it last between seedings. UMN suggests mowing a thin lawn very short, to about 1 inch, before overseeding so sunlight reaches the soil and the new seed gets going faster. Buhata's own suggestion: keep the seeded area evenly moist until the new grass is up.
Good to Know
Clemson warns that the extra watering, fertilizing and shade that come with a ryegrass overseeding can seriously set back centipede, zoysia and St. Augustine lawns in spring and early summer. The windows on this page come from Minnesota and South Carolina, so check your state's extension service for local dates before you buy seed.
FAQ
When should I overseed my lawn?
For a cool-season lawn, University of Minnesota Extension prefers mid-August to mid-September. In the South, Clemson says to overseed bermudagrass with ryegrass in fall, about 30 days before the first frost.
Can I overseed a St. Augustine or zoysia lawn?
Clemson advises against overseeding centipede, zoysia and St. Augustine with ryegrass, because it can badly damage them the next spring and early summer.
Should I aerate before overseeding?
They often go together. On bermudagrass, Clemson says to wait 30 days after core aerationLawn aerationPulling small plugs of soil out of a lawn with a core aerator, so air, water and roots can get through compacted soil and thatch. See more before overseeding with ryegrass so the holes can heal.
Do It in Buhata
Maintenance (Household X) and Calendar
Add "Overseed thin spots" to Maintenance in the Household X add-on each August, and put the seeding window on your Calendar.
Open BuhataRelated Terms and Categories
- Lawn aeration
Pulling small plugs of soil out of a lawn with a core aerator, so air, water and roots can get through compacted soil and thatch.
- Lawn care schedule
A year-round plan that puts each lawn job, from mowing height to seeding and fertilizing, in the season that suits your type of grass.
- Dethatching
Removing the layer of dead and living stems and roots that builds up between grass blades and the soil, once it grows thicker than about one-half inch.
- Lawn care cost
What a household pays for mowing and other yard work over a season, often priced per visit plus extra jobs such as aeration or leaf cleanup.
- Home garden
A garden at home where a household grows some of its own vegetables, herbs or fruit, in the ground, in raised beds or in containers.
Sources
University of Minnesota Extension, "Renovating a lawn for quality and sustainability"; UMN Extension, "Seeding and sodding home lawns"; UMN Extension, "Fall lawn care"; Clemson Home & Garden Information Center, "Overseeding With Ryegrass"; Clemson HGIC, "Should You Overseed Your Warm-Season Lawn?"
- extension.umn.edu/lawn-care/renovating-lawn-quality-and-sustainability
- extension.umn.edu/lawn-care/seeding-and-sodding-home-lawns
- extension.umn.edu/news/fall-lawn-care-3
- hgic.clemson.edu/factsheet/overseeding-with-ryegrass
- hgic.clemson.edu/should-you-overseed-your-warm-season-lawn
Last updated .