Lawn seed · Nov 11, 2026
Grass seed germination temperature chart
Germination chart
Days are approximate for seed sown in early autumn into warm soil; colder soil takes longer.
| Grass | Type | Soil to germinate | Days to germinate (fall-sown) | Source |
|---|---|---|---|---|
| Perennial ryegrass | Cool-season | above 50°F | 4–5 days | R, K |
| Tall fescue | Cool-season | above 50°F | 5–7 days | R, K |
| Kentucky bluegrass | Cool-season | above 50°F | 10–14 days | R, K |
| Bermudagrass | Warm-season | about 65°F | – | O |
| Zoysiagrass | Warm-season | warm soil; nights above 60°F | – | U |
- R: Rutgers Cooperative Extension turf blog, “Mild winter, what does it mean for overseeding of turf or dormant seeding?” (cool-season seed does not germinate until the soil stays above 50°F).
- K: Kansas State University Research and Extension, MF1126, Planting a Home Lawn (approximate germination times for fall-sown seed; seed cool-season grass in early September; dormant seeding once the soil averages under 40°F; warm-season grasses mid-May to July).
- O: Oklahoma State University Extension, PSS-2583 (bermudagrass seed does not germinate until the soil reaches about 65°F).
- U: University of Kentucky Cooperative Extension, AGR-50, Lawn Establishment in Kentucky (establish bermuda and zoysia in late May or June once the soil is warm, when nights stay above 60°F).
Cities in the cool-season seeding range today
Largest cities whose 5-day mean is 50–65°F.
| City | Soil today | 5-day mean |
|---|---|---|
| New York, NY | 58°F | 58°F |
| Chicago, IL | 54°F | 52°F |
| Philadelphia, PA | 57°F | 56°F |
| San Antonio, TX | 67°F | 65°F |
| San Jose, CA | 63°F | 61°F |
| Columbus, OH | 56°F | 53°F |
| Charlotte, NC | 64°F | 63°F |
| Indianapolis, IN | 58°F | 53°F |
| San Francisco, CA | 63°F | 62°F |
| Seattle, WA | 54°F | 52°F |
| Denver, CO | 57°F | 57°F |
| Washington, DC | 59°F | 57°F |
Reading the chart
Cool-season grasses (ryegrass, tall fescue, Kentucky bluegrass) do best seeded in late summer to early autumn, while the soil is still warm; they do not germinate until the soil stays above 50°F. Ryegrass comes up first and bluegrass last, which is why mixes look patchy at first. Seed sown on cold soil (averaging under 40°F) in late autumn simply waits and germinates in spring: that is “dormant seeding”. Warm-season grasses (bermuda, zoysia) wait for late spring and early summer: bermudagrass seed needs soil of about 65°F.
Keep the top inch of soil moist until the seedlings are up. Do not seed where a crabgrass pre-emergent went down this season unless its label allows it.
The 65°F upper limit used for “cool-season seed” verdicts on city pages is this site's rule of thumb for when seedlings start to struggle in heat; the sources above give the lower limits and timing. Follow the seed label.
Data: Global Forecast System (GFS) 0.25°, soil temperature 0–10 cm (TSOIL) (NOAA National Centers for Environmental Prediction (NCEP)); GeoNames gazetteer (cities15000) (GeoNames).