What to plant in March in the Southwest

Worked out for 8 cities from their own weather and frost dates, by zone.

What to sow and plant in March in the Southwest, by zone: frost-free, highs of 72–82 °F (Phoenix, Tucson and 2 more): zucchini, green beans, cucumber, sweet corn, basil and 8 more; frost-free, highs of 61–72 °F (Las Vegas): peas, radish, beet, zucchini, cucumber and 14 more; frost possible, highs of 61–72 °F (Albuquerque): peas, lettuce, radish, Swiss chard, beet and 16 more; frost possible, highs of 50–61 °F (Santa Fe (United States) and Flagstaff): broad bean, peas, onion, spinach, lettuce and 21 more.

In the Southwest, March is spring.

Frost-free, highs of 72–82 °F: Phoenix, Tucson, Yuma and Las Cruces

In March, on average, these cities have highs of 72 to 81 °F and lows of 45 to 54 °F, 0.4 to 1.3 in of rain on 2 to 4 days; the day lasts 11 h 56 min to 11 h 57 min (on the 15th).

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

How	What	Where
start indoors, plant out in April or sow direct	Zucchini, basil	all
sow direct	Green Beans	Phoenix, Tucson and Yuma
start indoors, plant out in April	Cucumber	Phoenix, Tucson and Las Cruces
sow direct	Sweet Corn, arugula, chayote, corn, Florence fennel, Napa cabbage	Phoenix, Tucson and Las Cruces
sow direct	Bok Choy, borage	all
sow direct	Kiwano	Phoenix and Tucson

Compared with February: no longer sown — peas, lettuce, radish, Swiss chard, beet, melon, watermelon, pumpkin and 10 more.

Not starting in March: tomato (January, started indoors), bell pepper (January, started indoors), lettuce (November, started indoors), peas (November, sown direct) and spinach (November, started indoors) — dates for Tucson.

Ready to harvest in March in Tucson, if sown in the right month: broad bean (December), peas (January), lettuce (January), radish (February), cabbage (November), broccoli (December), Swiss chard (January) and beet (January).

Frost-free, highs of 61–72 °F: Las Vegas

In March, on average, Las Vegas has highs of 68 °F and lows of 47 °F, 0.8 in of rain on 4 days; the day lasts 11 h 55 min (on the 15th). A dry month: whatever is sown needs watering.

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

How	What	Where
sow direct	Peas, radish, beet, sweet corn, parsley, cilantro, arugula, bok choy, borage, chamomile, chayote, corn, dill, Florence fennel, mustard greens, Napa cabbage	Las Vegas
start indoors, plant out in April	Zucchini, cucumber, basil	Las Vegas

Compared with February: new — borage, chayote, corn and Florence fennel; no longer sown — broad bean, onion, lettuce, cabbage, Swiss chard, melon, watermelon, pumpkin and 9 more.

Not starting in March: tomato (January, started indoors), bell pepper (January, started indoors), green beans (April, sown direct), lettuce (November, sown direct) and spinach (November, sown direct) — dates for Las Vegas.

Ready to harvest in March in Las Vegas, if sown in the right month: broad bean (December), peas (January), spinach (January), lettuce (January), radish (February), carrot (January), cabbage (November) and broccoli (December).

Frost dates in Las Vegas

Frost possible, highs of 61–72 °F: Albuquerque

In March, on average, Albuquerque has highs of 64 °F and lows of 37 °F, 1.1 in of rain on 6 days; the day lasts 11 h 56 min (on the 15th). A dry month: whatever is sown needs watering.

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

How	What	Where
sow direct	Peas, lettuce, radish, Swiss chard, beet, parsley, cilantro, arugula, chamomile, dill, kohlrabi, mustard greens	Albuquerque
start indoors, plant out in May	Tomato, bell pepper, eggplant, chili pepper, Florence fennel, moringa	Albuquerque
start indoors, plant out in June	Celeriac, celery, chayote	Albuquerque

Compared with February: new — tomato, bell pepper, eggplant, parsley, cilantro, chili pepper, dill, Florence fennel and 2 more; no longer sown — broad bean, onion, spinach, cabbage, daikon, kale, parsnip, shallot and 1 more.

Not starting in March: zucchini (April, started indoors), green beans (May, sown direct) and spinach (October, started indoors) — dates for Albuquerque.

Ready to harvest in March in Albuquerque, if sown in the right month: radish (February), cabbage (November) and arugula (February).

Frost dates in Albuquerque

Frost possible, highs of 50–61 °F: Santa Fe (United States) and Flagstaff

In March, on average, these cities have highs of 52 to 54 °F and lows of 30 to 32 °F, 1.1 to 1.7 in of rain on 7 days; the day lasts 11 h 55 min to 11 h 56 min (on the 15th).

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

How	What	Where
sow direct	Broad bean, spinach, cabbage, daikon, kale, parsnip, turnip	Santa Fe (United States)
sow direct	Peas, radish	all
plant sets	Onion, shallot	Santa Fe (United States)
sow direct or start indoors, plant out in April	Lettuce, Swiss chard, arugula, chamomile	all
start indoors, plant out in April	Beet, kohlrabi	all
start indoors, plant out in May	Tomato, bell pepper, eggplant, chili pepper, Florence fennel, moringa	Santa Fe (United States)
start indoors, plant out in June	Celeriac, celery, chayote	all

Compared with February: new — peas, onion, radish, cabbage, tomato, bell pepper, eggplant, chili pepper and 6 more; no longer sown — cauliflower and parsley.

Not starting in March: zucchini (May, started indoors) and green beans (June, sown direct) — dates for Flagstaff.

Ready to harvest in March in Flagstaff, if sown in the right month: cabbage (November).

How we work it out

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