What to plant in January in California

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

What to sow and plant in January in California, by zone: frost-free, highs of 61–72 °F (Los Angeles and San Diego): broad bean, peas, onion, spinach, lettuce and 29 more; frost possible, highs of 61–72 °F (Bakersfield and Riverside): broad bean, peas, onion, spinach, lettuce and 40 more; frost possible, highs of 50–61 °F (Fresno, Sacramento and 3 more): broad bean, peas, onion, spinach, lettuce and 27 more; frost-free, highs of 50–61 °F (San Francisco and San Jose): broad bean, peas, onion, spinach, lettuce and 24 more.

In California, January is winter.

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

In January, on average, these cities have highs of 64 to 66 °F and lows of 46 to 49 °F, 2.8 to 3.5 in of rain on 6 days; the day lasts 10 h 07 min to 10 h 13 min (on the 15th).

No frost in January 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, 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	San Diego
start indoors, plant out in February	Cauliflower	all
start indoors, plant out in March	Leek	San Diego
start indoors, plant out in March	Tomato, bell pepper, eggplant, chili pepper, Florence fennel, moringa	Los Angeles
start indoors, plant out in March	Brussels Sprouts	all
start indoors, plant out in April	Celeriac, celery, chayote	Los Angeles

Compared with December: new — tomato, bell pepper, eggplant, chili pepper, Florence fennel and moringa.

Not starting in January: zucchini (April, started indoors) and green beans (May, sown direct) — dates for San Diego.

Ready to harvest in January in San Diego, if sown in the right month: broad bean (October), peas (November), lettuce (November), radish (December), carrot (November), cabbage (September), Swiss chard (November) and beet (November).

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

In January, on average, these cities have highs of 62 to 67 °F and lows of 40 to 45 °F, 2.1 to 3.3 in of rain on 6 to 7 days; the day lasts 10 h 01 min to 10 h 08 min (on the 15th).

January falls in the frost season: frost-tender crops wait. Average last frost: Riverside (January 12).

How	What	Where
sow direct	Broad bean, peas, lettuce, radish, carrot, cabbage, broccoli, Swiss chard, beet, parsley, cilantro, arugula, chamomile, chickpea, daikon, dill, kale, kohlrabi, mustard greens, parsnip	all
plant sets	Onion, shallot	all
sow direct	Spinach	Bakersfield
start indoors, plant out in February	Cauliflower, zucchini, cucumber, melon, watermelon, pumpkin, sweet corn, basil, achocha, bok choy, kiwano, Napa cabbage, peanut	Riverside
start indoors, plant out in March	Tomato, bell pepper, eggplant, chili pepper, Florence fennel, moringa	all
start indoors, plant out in April	Celeriac, celery, chayote	Riverside

Compared with December: new — zucchini, cucumber, melon, watermelon, pumpkin, sweet corn, basil, chickpea and 5 more; no longer sown — turnip and Brussels sprouts.

Not starting in January: green beans (April, sown direct) — dates for Bakersfield.

Ready to harvest in January in Bakersfield, if sown in the right month: peas (November), lettuce (November), radish (December), carrot (November), Swiss chard (November), beet (November), parsley (November) and cilantro (November).

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

In January, on average, these cities have highs of 56 to 59 °F and lows of 39 to 41 °F, 3.0 to 8.3 in of rain on 7 to 14 days; the day lasts 9 h 35 min to 10 h 06 min (on the 15th).

January falls in the frost season: frost-tender crops wait.

How	What	Where
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 February	Cauliflower, kohlrabi	all
start indoors, plant out in March	Tomato, bell pepper, eggplant, chili pepper, Florence fennel, moringa	Fresno, Sacramento, Redding and 1 more
start indoors, plant out in March	Parsley	all
start indoors, plant out in April	Celeriac, celery, chayote	Sacramento, Santa Barbara and Stockton
start indoors, plant out in March	Brussels Sprouts	Santa Barbara

Compared with December: new — tomato, bell pepper, eggplant, chili pepper, Florence fennel and moringa; no longer sown — garlic, leek, cilantro and chicory.

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

Ready to harvest in January in Sacramento, if sown in the right month: peas (November), spinach (November), lettuce (November), radish (December), carrot (November), Swiss chard (November), beet (November) and pumpkin (September).

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

In January, on average, these cities have highs of 56 to 58 °F and lows of 43 to 47 °F, 4.8 in of rain on 10 to 11 days; the day lasts 9 h 50 min to 9 h 52 min (on the 15th).

No frost in January 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 February	Cauliflower	all
start indoors, plant out in March	Leek	San Francisco
start indoors, plant out in March	Brussels Sprouts	all
start indoors, plant out in April	Celeriac, celery, chayote	San Jose

Compared with December: new — celeriac, celery and chayote; no longer sown — chicory.

Not starting in January: 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 January in San Francisco, if sown in the right month: broad bean (October), peas (November), spinach (November), lettuce (November), radish (December), carrot (November), cabbage (September) and broccoli (October).

How we work it out

For each city we use its average weather in January 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 January 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.