Germination chart · 27 vegetables and 6 lawn grasses
Soil temperature for germination
Grass seed germination temperature
Cool-season and warm-season grasses: the soil temperature to seed and how long each takes.
Grass seed chartSoil temperature for tomatoes
Seed starting and planting out, and which cities' soil is warm enough today.
TomatoesCrabgrass pre-emergent
The 50–55°F window, state by state, from last spring's soil.
Crabgrass timingVegetable seed germination by soil temperature
°F. Below the minimum, little or no germination; the best range gives the most seedlings in good time.
| Crop | Minimum | Best range | Optimum | Maximum |
|---|---|---|---|---|
| Asparagus | 50°F | 60–85°F | 75°F | 95°F |
| Bean, lima | 60°F | 60–85°F | 85°F | 85°F |
| Bean, snap | 60°F | 65–85°F | 80°F | 95°F |
| Beet | 40°F | 50–85°F | 85°F | 85°F |
| Cabbage | 40°F | 45–95°F | 85°F | 100°F |
| Carrot | 40°F | 45–85°F | 80°F | 95°F |
| Cauliflower | 40°F | 45–85°F | 80°F | 100°F |
| Celery | 40°F | 60–70°F | 70°F | 85°F |
| Chard, Swiss | 40°F | 50–85°F | 85°F | 95°F |
| Corn (sweet) | 50°F | 60–95°F | 95°F | 105°F |
| Cucumber | 60°F | 60–95°F | 95°F | 105°F |
| Eggplant | 60°F | 75–90°F | 85°F | 95°F |
| Lettuce | 35°F | 40–80°F | 75°F | 85°F |
| Muskmelon (cantaloupe) | 60°F | 75–95°F | 90°F | 100°F |
| Okra | 60°F | 70–95°F | 95°F | 105°F |
| Onion | 35°F | 50–95°F | 75°F | 95°F |
| Parsley | 40°F | 50–95°F | 75°F | 95°F |
| Parsnip | 35°F | 50–70°F | 65°F | 85°F |
| Pea | 40°F | 40–75°F | 75°F | 85°F |
| Pepper | 60°F | 65–95°F | 85°F | 95°F |
| Pumpkin | 60°F | 70–90°F | 90°F | 100°F |
| Radish | 40°F | 45–90°F | 85°F | 95°F |
| Spinach | 35°F | 45–75°F | 70°F | 85°F |
| Squash | 60°F | 70–95°F | 95°F | 100°F |
| Tomato | 50°F | 70–95°F | 85°F | 95°F |
| Turnip | 40°F | 60–105°F | 85°F | 105°F |
| Watermelon | 60°F | 70–95°F | 95°F | 105°F |
Source: Alabama Cooperative Extension System, ANR-1061, Soil Temperature Conditions for Vegetable Seed Germination (revised 2023), Table 1; the figures trace back to J. F. Harrington, University of California, Davis (1954). Numbers are restated, not copied text.
Lawn grass seed
From named extension sources; the source letters are listed below the table.
| 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).
Use the soil temperature at seed depth, which for most seed is the top 2 inches; the model numbers on this site are the average of the top 4 inches. Germination is fastest near the optimum and slows sharply near the minimum. Follow the seed packet where it differs.
Data: Global Forecast System (GFS) 0.25°, soil temperature 0–10 cm (TSOIL) (NOAA National Centers for Environmental Prediction (NCEP)).