What to plant in October in the Southwest

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

What to sow and plant in October in the Southwest, by zone: frost-free, highs above 82 °F (Phoenix, Tucson and 1 more): zucchini, green beans, basil, bok choy and borage; frost-free, highs of 72–82 °F (Las Vegas, Albuquerque and 1 more): garlic; frost possible, highs of 61–72 °F (Santa Fe (United States) and Flagstaff): garlic, broad bean, peas, onion, spinach and 15 more.

In the Southwest, October is fall.

Frost-free, highs above 82 °F: Phoenix, Tucson and Yuma

In October, on average, these cities have highs of 87 to 92 °F and lows of 61 to 65 °F, 0.4 to 1.1 in of rain on 1 to 3 days; the day lasts 11 h 23 min to 11 h 25 min (on the 15th). A dry month: whatever is sown needs watering.

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

How	What	Where
sow direct	Zucchini, green beans, basil, bok choy, borage	all
start indoors, plant out in November	Cucumber, melon, achocha	Yuma
sow direct	Watermelon, pumpkin, sweet corn, chayote, corn, Florence fennel, kiwano, luffa, moringa, Napa cabbage, okra, peanut, soybean	Yuma
start indoors, plant out in January	Celeriac, celery	Yuma

Compared with September: new — melon, achocha, celeriac and celery.

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

Frost-free, highs of 72–82 °F: Las Vegas, Albuquerque and Las Cruces

In October, on average, these cities have highs of 73 to 81 °F and lows of 48 to 58 °F, 0.3 to 1.6 in of rain on 1 to 5 days; the day lasts 11 h 19 min to 11 h 25 min (on the 15th).

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

How	What	Where
plant cloves	Garlic	Albuquerque and Las Cruces
sow direct	Broad bean, peas, lettuce, carrot, cabbage, broccoli, Swiss chard, beet, parsley, cilantro, arugula, chamomile, chickpea, dill, kale, kohlrabi, mustard greens, parsnip	Albuquerque
plant sets	Onion, shallot	Albuquerque
start indoors, plant out in November	Spinach	Albuquerque
plant bulbs	Crocus, daffodil, hyacinth, tulip	Albuquerque

Compared with September: new — garlic, broad bean, peas, onion, spinach, lettuce, carrot, cabbage and 18 more; no longer sown — zucchini, green beans, watermelon, pumpkin, sweet corn, basil, bok choy, borage and 10 more.

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

Ready to harvest in October in Las Cruces, if sown in the right month: zucchini (August), green beans (August), basil (August), bok choy (August), borage (August), moringa (August), Napa cabbage (August) and soybean (August).

Frost possible, highs of 61–72 °F: Santa Fe (United States) and Flagstaff

In October, on average, these cities have highs of 65 °F and lows of 43 °F, 0.9 to 1.2 in of rain on 4 to 5 days; the day lasts 11 h 20 min (on the 15th).

October falls in the frost season: frost-tender crops wait. Average first frost: Santa Fe (United States) (October 26) and Flagstaff (October 21).

How	What	Where
plant cloves	Garlic	all
sow direct	Broad bean, peas, spinach, lettuce, radish, cabbage, broccoli, Swiss chard, beet, parsley, cilantro, arugula, chamomile, daikon, dill, kohlrabi, mustard greens	all
plant sets	Onion	all
plant bulbs	Crocus, daffodil, hyacinth, tulip	all

Compared with September: new — radish and daikon; no longer sown — chickpea and shallot.

Not starting in October: tomato (March, started indoors), bell pepper (March, started indoors), zucchini (April, started indoors) and green beans (June, sown direct) — dates for Santa Fe (United States).

Ready to harvest in October in Santa Fe (United States), if sown in the right month: zucchini (August), green beans (August), watermelon (July), pumpkin (June), sweet corn (July), basil (August), arugula (September) and bok choy (August).

How we work it out

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