USDA Zone 10 planting calendar
When to plant rosemary 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 rosemary in zone 10
| Stage | When | Anchor |
|---|---|---|
| Plant outdoors | year-round (avoid the hottest 6-8 weeks of summer for heat-sensitive varieties) | No frost — plant in the cool months |
| First harvest (estimate) | ~90 days after planting | ~90 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.
Start seeds indoors 10–12 weeks before the last frost; germination is slow and erratic (14–21 days at 18–21 °C / 65–70 °F) with low viability, so propagation by stem cuttings is preferred by most Extension services. Transplant outdoors after the last frost once soil has warmed — rosemary is perennial only in USDA zones 7–10 (established plants survive to about −12 °C / 10 °F); in zones 6 and colder treat as a tender annual or overwinter potted plants indoors before the first autumn frost. Tip harvests of stem ends begin around 80–100 days from transplant.
Quick-grow guide
- Sun: Full sun — 6+ hours direct.
- Soil temperature for germination: 18–21 °C (65–70 °F).
- Spacing: 18–36 inches (45–90 cm) between plants.
- Days to harvest from direct sow: ~90 days.
- Wait until night temperatures stay above 10 °C — cold soil stunts warm-season crops permanently.
Common mistakes — zone 10 × rosemary
- Planting before last frost: zone 10's last frost averages frost rare or never, and even a light frost will kill rosemary seedlings overnight.
- Skipping hardening off: even healthy indoor transplants need 7-10 days of progressive outdoor exposure before going in the ground.
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 rosemary — full guide
- USDA Zone 10 — frost dates and what else to plant
- All 13 USDA hardiness zones
Same crop, nearby zones
- When to plant rosemary in USDA zone 8
- When to plant rosemary in USDA zone 9
- When to plant rosemary in USDA zone 11
- When to plant rosemary in USDA zone 12