December in Zone 9
December in Zone 9 is active winter gardening — the cool-season garden is in full swing, citrus is at peak ripeness, and the mild climate allows continued planting, harvesting, and garden improvement right through the month.
Jump to another month
- Min Winter Temp
- 20 to 30 °F / -7 to -1 °C
- Last Spring Frost
- Late January – late February
- First Fall Frost
- Early December – early January
- Growing Season
- 270–310 days
- Annual Rainfall
- 10–55 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 9 last frost
- Late January – late February
- Zone 9 first frost
- Early December – early January
3
Sow indoors
4
Sow outdoors
0
Transplant
10
Harvest
7
Maintenance
🌱 Sow indoors
Start onions, leeks, and early flower seeds indoors
Late December is the right time to start long-season crops indoors that need 12–14 weeks of growth before outdoor transplanting in March–April. Onions, leeks, and slow-growing flowers benefit from early starts.
Onions
Sow ¼ inch deep in cell trays, 3–4 seeds per cell; thin to 1–2. Grow under lights at 65–70°F. December-started onions will be transplanted outdoors in March–April. Choose short-day varieties for Zone 9: 'Texas 1015 Supersweet', 'Granex Yellow', 'Red Burgundy'.
Leeks
Sow ¼ inch deep, 1 seed per cell, under grow lights. Leeks need 10–12 weeks to reach transplant size. December-started leeks are ready for outdoor transplanting in March for summer harvest.
Lisianthus
Lisianthus needs 5–6 months from seed to bloom — start in December for summer flowers. Sow on the surface of moist seed-starting mix; seeds need light to germinate. Keep at 70–75°F. One of the most rewarding cut flowers for Zone 9 summer gardens.
🌿 Sow outdoors
Direct sow fast-maturing cool-season crops
Despite the shortest days of the year, Zone 9's mild December temperatures allow continued sowing of fast-maturing crops. Radishes, Asian greens, and arugula all germinate and mature even in December's cool conditions.
Radishes
Sow ½ inch deep, 1 inch apart. Radishes mature in 25–35 days even in December's cool soil. French breakfast, Easter Egg mix, and daikon types all produce well. Succession sow every 2 weeks for continuous harvest.
Arugula
Broadcast and rake lightly into ¼ inch of soil. December arugula germinates in 7–10 days and produces the most intensely flavored arugula of the year in Zone 9. Grows slowly but steadily through the short-day season.
Spinach
Sow ½ inch deep, 2 inches apart. December-sown spinach grows slowly through the shortest days but accelerates in January–February as days lengthen. 'Bloomsdale' and 'Tyee' are both reliable for December sowing.
Mâche
Broadcast sow ¼ inch deep. Mâche is the most cold-tolerant salad green available — it thrives in Zone 9's December conditions and produces through March. Sweet, nutty flavor is excellent as a salad base.
🧺 Harvest
Peak winter harvest: brassicas, root vegetables, and greens
December delivers Zone 9's best cool-season harvests of the year. Carrots, beets, and parsnips are sweetened by cold nights, brassicas are at peak flavor and texture, and the garden requires daily or every-other-day harvesting to stay ahead of mature crops.
Carrots
September-sown carrots are fully mature in December. Harvest by loosening soil with a fork alongside the row and pulling by the tops. Leave some in the ground — carrots "hold" well in Zone 9's cool December soil for weeks and improve in sweetness with cold nights.
Beets
Harvest when roots are 2–3 inches in diameter. Leave smaller beets to continue growing; pull the largest first. Beet greens are also fully edible — harvest young inner leaves for salads, outer leaves for cooking.
Broccoli
Late-fall-planted broccoli heads ripen in December–January. Continue harvesting side shoots from earlier plantings — a well-managed plant can produce for 8–10 weeks after the main head is cut. Harvest every 3–5 days.
Kale
December kale is the sweetest and most tender of the year — cold nights convert starches to sugars. Harvest outer leaves from the base up. 'Lacinato', 'Red Russian', and 'Winterbor' are all excellent in Zone 9 December gardens.
Lettuce
September and October sowings of lettuce are at peak quality in December. Harvest entire heads or cut-and-come-again outer leaves. Cover with floating row cover if a hard frost (below 28°F) is forecast.
Peas
September-sown peas are producing pods in December in Zone 9. Check plants every 2 days for sugar snap types — pods become starchy quickly at cool temperatures. Snow peas can be harvested at any size.
Peak citrus harvest: navels, mandarins, and grapefruit
December is the height of Zone 9's citrus season. Navel oranges are at peak sweetness, grapefruit begins to ripen, and Meyer lemons are producing abundantly. Citrus harvest continues through February or March depending on variety.
Navel Orange
December navels are at peak sweetness — the cold nights of November–December convert sugars and develop complex flavor. Harvest with pruners, leaving a short stub of stem. Store at room temperature up to 2 weeks; refrigerate for longer storage.
Clementine
Clementines ripen in November–January in Zone 9. Harvest when fully orange, shiny, and fragrant. Clementines do not store as long as navels — harvest as needed or refrigerate. One mature tree produces hundreds of fruit.
Ruby Red Grapefruit
Grapefruit ripens December through March in Zone 9. Taste-test to determine ripeness — color is not a reliable indicator. Ripe grapefruit is heavy for its size and gives slightly under thumb pressure. Can be left on the tree for months after ripening.
Kumquat
Kumquats ripen November–February in Zone 9. Harvest when fully orange and sweet-tart. The entire fruit, skin and all, is edible — the skin is sweet and the flesh is tart. Productive, nearly frost-hardy, and excellent in marmalades and cocktails.
🛠️ Maintenance
Prune dormant deciduous fruit trees
December through February is the dormant pruning window for deciduous fruit trees in Zone 9. Trees are leafless, dormant, and disease pressure is low — the ideal conditions for structural pruning.
Apple
Prune to an open vase or central leader shape depending on variety. Remove crossing branches, water sprouts, and downward-growing wood. Make clean cuts just outside the branch collar. Apply dormant oil spray after pruning to smother overwintering scale and mite eggs.
Peach / Nectarine
Remove 40–50% of last year's growth — peaches fruit on one-year-old wood and need heavy pruning to remain productive. Keep the tree at a manageable height (6–8 feet). Apply copper fungicide spray after pruning to prevent peach leaf curl.
Plum
Prune moderately — remove dead, diseased, and crossing wood plus any branches growing into the center. European plums fruit on spurs; Japanese plums fruit on one-year-old wood — adjust pruning strategy accordingly.
Fig
Remove dead wood and shape the canopy in December. Figs fruit on new wood — shortening all branches by one-third encourages vigorous fruiting shoots in spring. Leave stumps with 2–3 buds for the best fruit production.
Plan, order seeds, and improve soil for next year
December is the ideal time for Zone 9 gardeners to review the year's successes and failures, plan the coming year's garden layout, and order seeds from catalogs before popular varieties sell out.
Seed Ordering
Order seeds from specialty catalogs by early January — heat-tolerant tomato varieties like 'Heatmaster', 'Solar Fire', and 'Arkansas Traveler' sell out quickly. Also order short-day onion varieties and heat-tolerant pepper and eggplant seeds for Zone 9's long season.
Soil Amendment Planning
Have soil tested now if not done in fall. Zone 9 soils (especially in arid areas) often have high pH, high salt content, and low organic matter. Plan to incorporate 3–4 inches of compost into all beds in February before spring planting begins.
Garden Layout Planning
Plan crop rotations to avoid planting the same family in the same bed in consecutive years. In Zone 9's two-season system, plan both the spring warm-season layout AND the fall cool-season layout simultaneously, as beds transition quickly between them.
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 9: common questions
What can I plant in December in Zone 9?＋
In December, Zone 9 gardeners can sow or transplant Onions, Leeks, Lisianthus, Radishes, Arugula, Spinach, and Mâche. December in Zone 9 is active winter gardening — the cool-season garden is in full swing, citrus is at peak ripeness, and the mild climate allows continued planting, harvesting, and garden improvement right through the month.
When is the last and first frost in Zone 9?＋
Zone 9 typically has its last spring frost around Late January – late February and its first fall frost around Early December – early January, giving a growing season of roughly 270–310 days. Always check a local frost-date source, since microclimates vary.
What's ready to harvest in December in Zone 9?＋
In December, Zone 9 gardeners are typically harvesting Carrots, Beets, Broccoli, Kale, Lettuce, Peas, Navel Orange, and Clementine. Pick regularly — frequent harvesting keeps most crops producing longer.