September · USDA Zone 10
autumnWhat to plant in September in USDA zone 10
Autumn planting guide for zone 10 (South Florida, Coastal Southern California, Hawaii (parts)) — a 365-day growing season with last frost around frost rare or never and first frost around frost rare or never.
Sow outdoors in September — zone 10
Direct-sow these seeds into prepared garden beds or large containers. Soil temperature matters more than the calendar date — wait for a sustained warm-up before sowing tender crops.
- Cool-season crops opening — lettuce, kale, broccoli transplants, carrots, beets
Transplant in September — zone 10
Move hardened-off seedlings into the garden. Tender crops want soil above 16 °C and night temperatures consistently above 10 °C; cool-season transplants tolerate light frost.
- Fall tomatoes, peppers, eggplant
Harvest in September — zone 10
These crops should be ready or in active harvest in September for zone 10 gardens. Pick fruiting crops every 2-3 days to keep production going.
- Tropical fruit, citrus, sweet potatoes, hot peppers
Prep and planning — zone 10
- Plan main growing season — October through March
Universal September tasks
These apply across most US and UK gardens in September, regardless of zone.
- Plant garlic (zones 3-5 — start of the window).
- Sow autumn salad, spinach, lettuce, radishes, and mache.
- Transplant fall brassicas if not done in August.
- Sow cover crops (winter rye, vetch, clover) on empty beds.
- Harvest and cure winter squash, pumpkins, and onions.
- Start collecting and saving heirloom seed from open-pollinated favorites.
Why this works for zone 10
Zone 10 has average annual minimum temperatures of 30 to 40°F (-1 to 4°C) and a frost-free window from frost rare or never to frost rare or never — about 365 growing days. Summer can be too hot for many tomato varieties. Winter is the prime growing season for cool-loving crops.
Dates are zone-wide averages. Local microclimates (south-facing slopes, urban heat, lakeside warmth, elevation) can shift the window by 1-2 weeks within the same zone.
UK gardeners — September
September starts the UK's autumn garden. Sow winter salad, spring cabbage, mustard, mizuna, and overwintering onions. Plant garlic and overwintering broad beans late month. Harvest apples, pears, plums, sweetcorn, and main-crop potatoes.
Source and methodology
Frost-date averages from NOAA Climate Data Online within USDA zone 10. Hardiness boundaries from the USDA Plant Hardiness Zone Map (2023). Crop timing curated against US Cooperative Extension Service publications (UNL, UMN, NC State, Texas A&M, UF/IFAS, Oregon State) and cross-referenced against the RHS sowing calendar. Curated by the Growli editorial team.
Keep going
- ← August in zone 10
- October in zone 10 →
- All zones — what to plant in September
- USDA Zone 10 — frost dates and crop list
- Full 12-month planting calendar