Radish Soil Temperature Guide
A mid-season crop that germinates best in moderately warm soil.
| Minimum germination temp | 55°F (12.8°C) |
|---|---|
| Optimal germination temp | 65°F (18.3°C) |
| Maximum germination temp | 85°F (29.4°C) |
| Danger zone | Below 55°F — seeds rot or fail to sprout |
Is your soil warm enough for Radish?
Minimum needed: 55°F
Why soil temperature matters for radish
Soil temperature directly controls enzyme activity inside radish seeds. Below 55°F (12.8°C), germination slows dramatically or fails entirely—seeds may rot before they sprout.
When to plant radish in your region
Sow radish outdoors when your soil consistently reads 55°F (12.8°C) at 4-inch depth. For the fastest germination, wait until it reaches 65°F (18.3°C).
Signs your soil is ready
The easiest method is to track your local soil temperature forecast until it's predicted to stay above 55°F for the next 7 days—sign up for notifications when it's time to plant radish. For more precise readings in raised beds, pots, or different spots in the garden, push a soil thermometer 4 inches deep in the early morning.