Seed-start answer
Radishes is usually direct-sown around Jan 18
In ZIP 85701, radishes is usually direct-sown around Jan 18 instead of started indoors.
Source: tucson-intl frost station, USDA zone 9b, last updated 2026-06-28. Verify locally before planting high-value crops because microclimates, current weather, and yard exposure can move the safe date.
This uses ZIP 85701, the Tucson frost station, and the Feb 15 last-frost estimate.
Seed starting schedule
Radishes dates for Tucson, AZ
| Step | Date | How to use it |
|---|---|---|
| Direct Sow | January 18, 2026 | Sow seed outside when the crop and soil can handle the window. |