What to plant in December in California

Worked out for 11 cities from their own weather and frost dates, by zone.

What to sow and plant in December in California, by zone: frost-free, highs of 61–72 °F (Los Angeles and San Diego): broad bean, peas, onion, spinach, lettuce and 23 more; frost possible, highs of 61–72 °F (Bakersfield and Riverside): broad bean, peas, onion, spinach, lettuce and 29 more; frost possible, highs of 50–61 °F (Fresno, Sacramento and 3 more): garlic, broad bean, peas, onion, spinach and 23 more; frost-free, highs of 50–61 °F (San Francisco and San Jose): broad bean, peas, onion, spinach, lettuce and 22 more.

In California, December is winter.

Frost-free, highs of 61–72 °F: Los Angeles and San Diego

In December, on average, these cities have highs of 65 to 68 °F and lows of 47 to 49 °F, 2.1 to 3.1 in of rain on 5 days; the day lasts 9 h 54 min to 10 h 01 min (on the 15th).

No frost in December in 10 years of data: frost-tender crops can go in too, if it is warm enough for them.

How	What	Where
sow direct	Broad bean, peas, spinach, lettuce, radish, carrot, cabbage, broccoli, Swiss chard, beet, parsley, cilantro, arugula, chamomile, daikon, dill, kale, kohlrabi, mustard greens, parsnip	all
plant sets	Onion, shallot	all
start indoors, plant out in January	Cauliflower	all
start indoors, plant out in February	Leek	San Diego
start indoors, plant out in February	Brussels Sprouts	all
start indoors, plant out in March	Celeriac, celery, chayote	Los Angeles

Compared with November: new — radish, daikon, celeriac, celery and chayote; no longer sown — chickpea.

Not starting in December: tomato (March, started indoors), bell pepper (March, started indoors), zucchini (April, started indoors) and green beans (May, sown direct) — dates for San Diego.

Ready to harvest in December in San Diego, if sown in the right month: broad bean (September), peas (October), cabbage (August), beet (October), zucchini (October), green beans (October), watermelon (September) and pumpkin (August).

Frost possible, highs of 61–72 °F: Bakersfield and Riverside

In December, on average, these cities have highs of 61 to 69 °F and lows of 40 to 46 °F, 2.0 to 2.7 in of rain on 5 to 6 days; the day lasts 9 h 47 min to 9 h 55 min (on the 15th).

December falls in the frost season: frost-tender crops wait. Average first frost: Bakersfield (December 14) and Riverside (December 19).

How	What	Where
sow direct	Broad bean, peas, lettuce, radish, carrot, cabbage, broccoli, Swiss chard, beet, parsley, cilantro, arugula, chamomile, daikon, dill, kale, kohlrabi, mustard greens, parsnip	all
plant sets	Onion, shallot	all
sow direct	Spinach, turnip	Bakersfield
start indoors, plant out in January	Cauliflower	all
start indoors, plant out in February	Tomato, bell pepper, eggplant, Brussels sprouts, chili pepper, Florence fennel, moringa	Riverside
start indoors, plant out in March	Celeriac, celery, chayote	all

Compared with November: new — radish, tomato, bell pepper, eggplant, daikon, chili pepper, Florence fennel, moringa and 1 more; no longer sown — chickpea.

Not starting in December: zucchini (February, started indoors) and green beans (April, sown direct) — dates for Bakersfield.

Ready to harvest in December in Bakersfield, if sown in the right month: zucchini (October), green beans (October), basil (October), arugula (November), bok choy (October), borage (October), dill (November) and mustard greens (November).

Frost possible, highs of 50–61 °F: Fresno, Sacramento, Santa Barbara, Redding and 1 more

In December, on average, these cities have highs of 56 to 60 °F and lows of 40 to 41 °F, 2.7 to 6.5 in of rain on 6 to 11 days; the day lasts 9 h 17 min to 9 h 52 min (on the 15th).

December falls in the frost season: frost-tender crops wait. Average first frost: Fresno (December 5), Sacramento (December 11), Santa Barbara (December 15), Redding (December 11) and Stockton (December 3).

How	What	Where
plant cloves	Garlic	all
sow direct	Broad bean, peas, spinach, lettuce, radish, carrot, cabbage, broccoli, Swiss chard, beet, arugula, chamomile, daikon, dill, kale, mustard greens, parsnip, turnip	all
plant sets	Onion, shallot	all
start indoors, plant out in January	Cauliflower	all
start indoors, plant out in February	Leek	Santa Barbara
start indoors, plant out in February or sow direct	Parsley	all
sow direct	Cilantro	Santa Barbara
start indoors, plant out in February	Brussels Sprouts	all
start indoors, plant out in January or sow direct	Kohlrabi	all
start indoors, plant out in March	Celeriac, celery, chayote	Fresno, Sacramento, Redding and 1 more
start indoors, plant out in January	Chicory	Redding

Compared with November: new — celeriac, celery and chayote.

Not starting in December: tomato (January, started indoors), bell pepper (January, started indoors), zucchini (February, started indoors) and green beans (April, sown direct) — dates for Sacramento.

Ready to harvest in December in Sacramento, if sown in the right month: radish (November), watermelon (September), sweet corn (September), arugula (November), corn (September), dill (November), Florence fennel (September) and kiwano (September).

Frost-free, highs of 50–61 °F: San Francisco and San Jose

In December, on average, these cities have highs of 56 to 58 °F and lows of 44 to 47 °F, 4.3 to 5.2 in of rain on 10 to 11 days; the day lasts 9 h 34 min to 9 h 37 min (on the 15th).

No frost in December in 10 years of data: frost-tender crops can go in too, if it is warm enough for them.

How	What	Where
sow direct	Broad bean, peas, spinach, lettuce, radish, carrot, cabbage, broccoli, Swiss chard, beet, parsley, cilantro, arugula, chamomile, daikon, dill, kale, kohlrabi, mustard greens, parsnip, turnip	all
plant sets	Onion, shallot	all
start indoors, plant out in January	Cauliflower	all
start indoors, plant out in February	Leek	San Jose
start indoors, plant out in February	Brussels Sprouts	all
start indoors, plant out in January	Chicory	San Jose

The same as in November.

Not starting in December: tomato (no month outdoors by these rules), bell pepper (no month outdoors by these rules), zucchini (no month outdoors by these rules) and green beans (no month outdoors by these rules) — dates for San Francisco.

Ready to harvest in December in San Francisco, if sown in the right month: broad bean (September), peas (October), spinach (October), lettuce (October), radish (November), carrot (October), cabbage (August) and broccoli (September).

How we work it out

For each city we use its average weather in December and the months after (highs, lows and rain for 2016–2025, ERA5 reanalysis via Open-Meteo) and its average frost dates. A crop starts in December if the month's mean temperature reaches the minimum soil temperature for germination on its card (we use the mean air temperature as a stand-in for the soil's) and if, over its first months (up to three), the average highs stay within its group's range, with no frost for crops that cannot take it. Crops started indoors count from the month they are planted out.

Temperature groups from Colorado State University Extension: cool-season crops prefer 60–80 °F and lose quality in heat; hardy ones grow in days as cool as 40 °F, semi-hardy ones from 40–50 °F (we use 50 °F); warm-season crops need days above 55 °F, and the most tender (tomato, pepper, eggplant, melon, watermelon, squash) above 60 °F, up to 95 °F. Crops the guide does not name go into the stricter group by their frost hardiness. Fava (broad) beans, which the guide does not name, count as hardy: hardy varieties are sown in fall and overwinter (RHS). Garlic and bulbs: a month before the first frost, and later only while the ground is not frozen (as on each city's page).

This is a general rule from averages: your garden can be a week or two earlier or later, and a greenhouse or a cold frame brings the season forward. Greenly works out the dates for your location.