December · USDA Zone 9
winterWhat to plant in December in USDA zone 9
Winter planting guide for zone 9 (Central + South Florida, Southern Texas, Southern California, Arizona) — a 280-day growing season with last frost around mid-February to early March and first frost around late November / early December.
Sow outdoors in December — zone 9
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.
Transplant in December — zone 9
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.
- Cool-season transplants — main season
Harvest in December — zone 9
These crops should be ready or in active harvest in December for zone 9 gardens. Pick fruiting crops every 2-3 days to keep production going.
- Fall tomatoes (finishing), peppers, citrus, cool-season greens, broccoli, cauliflower
Maintenance in December — zone 9
- Frost protection on rare cold nights
Universal December tasks
These apply across most US and UK gardens in December, regardless of zone.
- Review this year's garden journal — what worked, what didn't, what to change.
- Start your seed list for next year while pleasure and pain are fresh.
- Check stored crops weekly for rot — winter squash, onions, garlic, potatoes.
- Force amaryllis and paperwhite bulbs for indoor color.
- Tend houseplants — many slow-grow now, so reduce watering by half.
- Prune dormant fruit trees and grapes on a dry, mild day.
Why this works for zone 9
Zone 9 has average annual minimum temperatures of 20 to 30°F (-7 to -1°C) and a frost-free window from mid-February to early March to late November / early December — about 280 growing days. Heat-tolerant tomato varieties (Solar Fire, Heatwave II) needed for midsummer. Cool-season crops grow Oct-Apr while northern zones are dormant.
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 — December
December is the UK's quiet month. Harvest brussels sprouts, leeks, parsnips, kale, and overwintered chard. Plant bare-root fruit trees and bushes on mild days. Force rhubarb crowns indoors. Plan next year and order seeds.
Source and methodology
Frost-date averages from NOAA Climate Data Online within USDA zone 9. 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
- ← November in zone 9
- January in zone 9 →
- All zones — what to plant in December
- USDA Zone 9 — frost dates and crop list
- Full 12-month planting calendar