USDA Zone 10 planting calendar
When to plant radishes in USDA zone 10
Sowing, transplant, and harvest dates calibrated to zone 10's 365-day season (South Florida, Coastal Southern California, Hawaii (parts)).
Key dates for radishes in zone 10
| Stage | When | Anchor |
|---|---|---|
| Direct sow outdoors | October — February (the cool dry season is your spring) | No frost — plant in the cool months |
| First harvest (estimate) | ~28 days after sowing | ~28 days from sow |
Dates are zone-wide averages. Local microclimates (south-facing slopes, urban heat, lakeside warmth, elevation) can shift the planting window by 1-2 weeks within the same zone.
Why this timing works for zone 10
Zone 10 has average annual minimum temperatures of 30 to 40°F and a 365-day frost-free window from frost rare or never to frost rare or never. Radishes are hardy enough to handle light frost — and in fact prefer cool weather. They bolt or turn bitter once daytime temperatures consistently climb above 24 °C, which is why earlier is better in zone 10.
Radishes are the fastest root crop — spring types mature in 22-30 days from direct sowing, making them ideal row-markers alongside slower crops. Sow 2-4 weeks before the last spring frost as soon as soil can be worked; they bolt and become pithy and peppery hot if left too long in warming soil. Succession-sow every 7-10 days for a continuous harvest; daikon and winter types sown in late summer take 50-70 days and tolerate heavier frost.
Quick-grow guide
- Sun: Full sun — 6+ hours direct.
- Soil temperature for germination: 7-29 °C (45-85 °F).
- Spacing: 2-3 inches (5-8 cm) between plants.
- Days to harvest from direct sow: ~28 days.
- Plant in cool weather and provide afternoon shade once temperatures climb above 24 °C.
Common mistakes — zone 10 × radishes
- Spring planting: zone 10 springs are too short — sow radishes in autumn for a winter and early-spring harvest instead.
- Waiting for "warm" soil — these crops germinate at 7-10 °C and bolt the moment summer heat sets in.
Source and methodology
Frost-date averages from NOAA Climate Data Online within each USDA hardiness zone. Hardiness zone boundaries from the USDA Plant Hardiness Zone Map (2023). Crop timing offsets calibrated against US Cooperative Extension Service publications (UNL, UMN, NC State, Texas A&M, UF/IFAS) and cross-checked against the RHS sowing calendar for en-GB readers. Curated by the Growli editorial team.
Keep going
- How to grow radishes — full guide
- USDA Zone 10 — frost dates and what else to plant
- All 13 USDA hardiness zones
Same crop, nearby zones
- When to plant radishes in USDA zone 8
- When to plant radishes in USDA zone 9
- When to plant radishes in USDA zone 11