Soil Temperature Map: What’s Your Dirt Doing Right Now?
Seeds don’t read air forecasts. Enter a ZIP code for your live soil temperature, the two-week trend, a regional soil-temp map, and exactly what’s warm enough to plant today.
The forecast your seeds actually follow
Soil lags air by weeks — it’s the flywheel of the garden. A 75°F April afternoon can sit on 48°F soil that rots bean seed, and a crisp September morning can hide 65°F soil that’s perfect for grass seed. Every planting decision that matters — corn, tomatoes, fall lawns, crabgrass pre-emergent — keys off the number this page reads, not the weather app.
Soil temperature planting thresholds
| Crop | Minimum soil temp | The practical read |
|---|---|---|
| Spinach, lettuce, peas, mâche | 35–40°F | The cold-soil pioneers — first in, and happy about it |
| Kale, radishes, beets, carrots | 40–45°F | Reliable germination once soil holds the low 40s |
| Potatoes (seed pieces) | 45°F | Colder soil rots seed potatoes before they sprout |
| Sweet corn | 50°F | The classic “soil at 50” benchmark — earlier plantings just sit |
| Cool-season grass seed | 50–65°F | Fall seeding window: warm soil + cool air is the magic combo |
| Crabgrass pre-emergent | ~55°F | Apply as soil approaches 55°F for several days running (spring) |
| Beans, cucumbers | 60°F | Below this they germinate slowly or rot |
| Tomato & pepper transplants | 60°F+ | Air temps lie — wait for the soil, not the sunshine |
| Squash, melons, okra | 65–70°F | True warm-soil crops; mulch black plastic to hurry it |
Measure like the pros if you want ground truth: a soil thermometer 2–3 inches deep, read at 9–10 am (the daily low point for soil), averaged over three days. This page’s modeled reading tells you when that walk outside is worth taking.
Soil temperature FAQ
Soil temperature is modeled at 6 cm depth via Open-Meteo’s land-surface model. Pairs with: frost dates for your ZIP · first frost by state · fall foliage forecast · tick forecast for the yard work that comes with warming soil.