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Zone 9A — December

What to Plant in December in Zone 9A

December in Zone 9A: 1 crop to start indoors, 0 to plant or direct sow outside, and 46 entering harvest window. Last frost averages March 4. Reference city: Phoenix, AZ.
Updated May 13, 2026 · Frost data from NOAA 1991-2020 Climate Normals
1 Start Indoors
0 Plant Outside
46 Harvest
Frost risk: High

Frost risk is still high in Zone 9A. The last spring frost typically lands on March 4, with the earliest plausible clearance around February 5. Hold tender crops indoors a while longer.

See full Zone 9A frost outlook →

Start Indoors in December

Plant Type Start Indoors Transplant Outside Harvest Window
Texas 1015Y SuperSweet Onion root vegetable Dec 31 Feb 4 May 20 – May 30

Plant Outside in December

Nothing to plant or sow outside in December for Zone 9A.
Next window: January — 78 varieties, including All Year Round, America, Astro Arugula.

Harvest in December

Plant Type Planted / Sown Harvest Window
All Year Round (fall planting) lettuce Oct 1 Dec 13
All Year Round Cauliflower (fall planting) brassica Oct 1 Dec 5
Bouquet Dill (fall planting) herb Oct 1 Dec 5
Broccolini (fall planting) brassica Oct 1 Dec 10
Butterhead Lettuce (fall planting) lettuce Oct 1 Dec 5
Calabrese Broccoli (fall planting) brassica Oct 1 Dec 5
California Bluebell (fall planting) flower Oct 1 Dec 5
Cascadia Sugar Snap Pea (fall planting) legume Oct 1 Dec 7
Chantenay Carrots (fall planting) root vegetable Oct 1 Dec 10
Chioggia Beet (fall planting) root vegetable Oct 1 Dec 5
Copenhagen Cabbage (fall planting) brassica Oct 1 Dec 5
Curly Kale (fall planting) lettuce Oct 1 Dec 5
Dark Green Romaine (fall planting) lettuce Oct 1 Dec 10
Di Cicco Broccoli (fall planting) brassica Oct 1 Dec 5
Early Purple Broccoli (fall planting) brassica Oct 1 Dec 5
Endive / Escarole (fall planting) lettuce Oct 1 Dec 5
German Chamomile (fall planting) herb Oct 1 Dec 5
Golden Acre Cabbage (fall planting) brassica Oct 1 Dec 5
Golden Beet (fall planting) root vegetable Oct 1 Dec 5
Green Arrow Pea (fall planting) legume Oct 1 Dec 10
Igloo Cauliflower (fall planting) brassica Oct 1 Dec 10
Kuroda Carrots (fall planting) root vegetable Oct 1 Dec 10
Lacinato Kale (fall planting) lettuce Oct 1 Dec 5
Little Marvel Pea (fall planting) legume Oct 1 Dec 3
Mammoth Dill (fall planting) herb Oct 1 Dec 5
Michihili Cabbage (fall planting) brassica Oct 1 Dec 10
Oregon Sugar Pod Snow Pea (fall planting) legume Oct 1 Dec 8
Progress No. 9 Shelling Pea (fall planting) legume Oct 1 Dec 2
Purple Haze Carrots (fall planting) root vegetable Oct 1 Dec 13
Rapeseed Cover Crop (fall planting) cover crop Oct 1 Dec 10
Rapini Broccoli Raab (fall planting) brassica Oct 1 Dec 5
Red Romaine (fall planting) lettuce Oct 1 Dec 10
Scarlet Flax Flowers (fall planting) flower Oct 1 Dec 10
Shelling Pea (fall planting) legume Oct 1 Dec 10
Snow Pea (fall planting) legume Oct 1 Dec 10
Snowball Self-Blanche Cauliflower (fall planting) brassica Oct 1 Dec 5
St. Valery Carrots (fall planting) root vegetable Oct 1 Dec 10
Tendersweet Carrots (fall planting) root vegetable Oct 1 Dec 10
Tom Thumb (fall planting) lettuce Oct 1 Dec 10
Vienna Purple Kohlrabi (fall planting) brassica Oct 1 Dec 5
Vienna White Kohlrabi (fall planting) brassica Oct 1 Dec 5
Viola and pansy edible flowers (fall planting) flower Oct 1 Dec 10
Violetta Purple Cauliflower (fall planting) brassica Oct 1 Dec 5
Wando Pea (fall planting) legume Oct 1 Dec 8
Watermelon Radishes (fall planting) root vegetable Oct 1 Dec 5
White Lisbon Bunching Onions (fall planting) root vegetable Oct 1 Dec 5

Key Tasks for December in Zone 9A

  1. 1 Start 1 variety indoors this month under grow lights or in a sunny south-facing window. Use a seed-starting mix and bottom heat (70–75°F) for best germination rates.
  2. 2 Check soil moisture before watering — stick a finger 2 inches into the soil. Water only when the soil is dry at that depth. Consistent moisture is more important than frequency.
Back to full Zone 9A planting calendar
November December in Zone 9A January

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