December in Zone 12
December in Zone 12 (last frost none, first frost none). There are 18 crops to sow, transplant, or harvest this month.
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- Min Winter Temp
- 50 to 60 °F / 10 to 16 °C
- Last Spring Frost
- None
- First Fall Frost
- None
- Growing Season
- Year-round (365 days)
- Annual Rainfall
- 20–100 in
December overview
December is the quietest month in cold-zone gardens. Planning, education, and equipment preparation fill the time. In warm zones, cool-season gardens are fully active and the holiday season includes fresh garden harvests. The winter solstice marks the turning point toward longer days.
Garden planning and seed catalog browsing in cold zones; active harvesting in warm zones; holiday greens; equipment maintenance; reflection and planning for the year ahead.
- Season
- winter
- Temperature trend
- Coldest period begins; winter solstice (shortest day) around December 21.
- Daylight
- Shortest days of the year; winter solstice around December 21 marks the turning point.
- Zone 12 last frost
- None
- Zone 12 first frost
- None
6
Sow indoors
9
Sow outdoors
3
Transplant
0
Harvest
1
Maintenance
🌱 Sow indoors
Start these indoors
Get a jump on the season under lights or on a sunny windowsill so transplants are ready when the weather warms.
Tomatoes
Sow ¼ in deep in cell trays; keep at 70–75°F. Germinates in 7–10 days.
Tomatillos
Sow ¼ in deep at 70°F; treat like tomatoes.
Broccoli
Sow ¼ in deep; ready to transplant in 4–6 weeks at 4–5 in tall.
Cabbage
Sow ¼ in deep; harden off well before setting out.
Basil
Surface-sow under lights at 70°F; very frost-tender.
Marigolds
Sow ¼ in deep; quick and reliable from seed.
🌿 Sow outdoors
Sow these directly outdoors
Soil and weather are right to sow these straight into the garden where they will grow.
Peas
Sow 1 in deep, 2 in apart as soon as soil is workable; trellis tall types.
Lettuce
Surface-sow and barely cover; succession-sow every 2 weeks for a steady supply.
Spinach
Sow ½ in deep in cold soil; bolts fast once days lengthen and warm.
Radishes
Sow ½ in deep, thin to 1 in. Ready in just 3–4 weeks — great for kids and impatient gardeners.
Carrots
Sow ¼ in deep in loose, stone-free soil; keep surface moist until sprouts appear (2–3 weeks).
Beets
Sow ½ in deep; each "seed" is a cluster, so thin to 3 in. Eat the thinnings as greens.
Kale & collards
Sow ¼ in deep or transplant; extremely cold-hardy.
Cilantro
Sow ½ in deep; succession-sow — it bolts quickly in heat.
Sweet peas
Soak seed, sow 1 in deep in cool soil, and give them something to climb.
🪴 Transplant
Transplant these into the garden
Move hardened-off seedlings into their final beds.
Broccoli
Transplant while still cool; space 18 in apart. Heat ruins the heads.
Cabbage
Transplant 12–18 in apart into firm soil while weather is still cool.
Onions
Set out pencil-thick seedlings (or sets) 4 in apart as soon as soil is workable.
🛠️ Maintenance
Harden off and prep beds
Zone 12's last frost lands around now (None).
📌 Harden off indoor seedlings over 7–10 days, work compost into beds, and keep frost cloth handy for surprise late freezes.
General December tasks
These apply broadly regardless of zone — a useful checklist alongside the zone-specific tasks above.
- ✓Review what worked and what didn't in this year's garden — take notes
- ✓Browse seed catalogs and create wish list for next season
- ✓Clean, sharpen, and oil all garden tools before storage
- ✓Service lawn mower and garden equipment
- ✓Harvest fresh winter vegetables in warm zones (Zones 8–13)
- ✓Force spring bulbs indoors for winter bloom: paperwhites, amaryllis
- ✓Order bare-root trees, roses, and fruit plants for late winter planting
- ✓Repot and refresh houseplants; take cuttings of favorite tender plants
⚠ Watch-outs for December
- ⚠Monitor cold frames and low tunnels during cold snaps — ventilate on warm days
- ⚠Salt and ice-melt products damage nearby plants — use sand or kitty litter instead
- ⚠Holiday plants (poinsettia, cyclamen) need cool, bright locations to last through the season
- ⚠Check stored produce (potatoes, squash, apples) and remove any showing rot
December in Zone 12: common questions
What can I plant in December in Zone 12?＋
In December, Zone 12 gardeners can sow or transplant Tomatoes, Tomatillos, Broccoli, Cabbage, Basil, Marigolds, Peas, and Lettuce. December in Zone 12 (last frost none, first frost none). There are 18 crops to sow, transplant, or harvest this month.
When is the last and first frost in Zone 12?＋
Zone 12 typically has its last spring frost around None and its first fall frost around None, giving a growing season of roughly 365–365 days. Always check a local frost-date source, since microclimates vary.
What garden jobs matter most in December in Zone 12?＋
Focus on review what worked and what didn't in this year's garden — take notes, browse seed catalogs and create wish list for next season, clean, sharpen, and oil all garden tools before storage. Watch out for monitor cold frames and low tunnels during cold snaps — ventilate on warm days.