USDA Zone 9 planting calendar
When to plant rosemary in USDA zone 9
Sowing, transplant, and harvest dates calibrated to zone 9's 280-day season (Central + South Florida, Southern Texas, Southern California, Arizona).
Key dates for rosemary in zone 9
| Stage | When | Anchor |
|---|---|---|
| Indoor seed start | mid-December (December 16) | 10 weeks before last frost |
| Outdoor transplant | early March (March 10) | 14 days after last frost (mid-February to early March) |
| First harvest (estimate) | early June (June 8) | ~90 days from transplant |
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 9
Zone 9 has average annual minimum temperatures of 20 to 30°F and a 280-day frost-free window from mid-February to early March to late November / early December.
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 transplant: ~90 days.
- Wait until night temperatures stay above 10 °C — cold soil stunts warm-season crops permanently.
Common mistakes — zone 9 × rosemary
- Planting before last frost: zone 9's last frost averages mid-February to early March, 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 9 — frost dates and what else to plant
- All 13 USDA hardiness zones
Same crop, nearby zones
- When to plant rosemary in USDA zone 7
- When to plant rosemary in USDA zone 8
- When to plant rosemary in USDA zone 10
- When to plant rosemary in USDA zone 11