GreenlyWhat to plant in August in the Southwest
Worked out for 8 cities from their own weather and frost dates, by zone.
What to sow and plant in August in the Southwest, by zone: frost-free, highs of 72–82 °F (Santa Fe (United States) and Flagstaff): zucchini, green beans, basil, bok choy and borage.
In the Southwest, August is summer.
Frost-free, highs above 82 °F: Phoenix, Las Vegas, Albuquerque, Tucson and 2 more
In August, on average, these cities have highs of 91 to 108 °F and lows of 66 to 83 °F, 0.2 to 1.8 in of rain on 2 to 7 days; the day lasts 13 h 21 min to 13 h 34 min (on the 15th).
No frost in August 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, watermelon, pumpkin, sweet corn, basil, bok choy, borage, chayote, corn, Florence fennel, kiwano, luffa, moringa, Napa cabbage, okra, peanut, soybean | Albuquerque and Las Cruces |
| start indoors, plant out in September | Cucumber | Albuquerque and Las Cruces |
Compared with July: no longer sown — melon and achocha.
Not starting in August: 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 August in Tucson, if sown in the right month: chayote (March).
Frost-free, highs of 72–82 °F: Santa Fe (United States) and Flagstaff
In August, on average, these cities have highs of 82 °F and lows of 60 °F, 1.3 to 2.0 in of rain on 7 to 10 days; the day lasts 13 h 30 min to 13 h 32 min (on the 15th).
No frost in August 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 |
Compared with July: no longer sown — cucumber, watermelon, pumpkin, sweet corn, chayote, corn, Florence fennel, kiwano and 6 more.
Not starting in August: tomato (March, started indoors), bell pepper (March, started indoors), lettuce (September, started indoors), peas (September, sown direct) and spinach (September, started indoors) — dates for Santa Fe (United States).
Ready to harvest in August in Santa Fe (United States), if sown in the right month: zucchini (June), green beans (June), sweet corn (May), basil (June), bok choy (June), borage (June), corn (May) and Florence fennel (May).
How we work it out
For each city we use its average weather in August 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 August 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.
- Moon planting calendar for August 2027
- What to plant in August: all climates
- Gardening in the United States: guide by region
