When to Plant in Arizona

Arizona's desert climate turns the traditional gardening calendar on its head. In the low desert around Phoenix and Tucson, the prime growing season is fall through spring — summer temperatures above 110°F make most vegetable gardening impossible.

Northern Arizona around Flagstaff and Prescott has a completely different climate with cold winters and a short summer growing season similar to northern states. The key to success in Arizona is knowing your specific elevation and microclimate.

Common Mistakes

Trying to garden in Phoenix during July and August — 110°F heat kills most vegetables regardless of watering.
Not taking advantage of the mild winter growing season in the low desert — October through March is prime time.
Underwatering in the desert — daily watering may be necessary during hot, dry periods.
Assuming Flagstaff and Phoenix have similar climates — they're in completely different growing zones.

FAQ

What is the last frost date?

The last frost date is the typical date in spring when your area has its final frost. In the low desert, frost is rare. In northern Arizona, last frost can be as late as mid-June.

When should I start tomatoes indoors in Arizona?

In the low desert, start tomato seeds in December or January for a spring harvest. In northern Arizona, start seeds indoors in March or April depending on elevation.

Can I plant before the last frost?

Yes — cool-season crops like lettuce, peas, spinach, and broccoli can handle light frost. In the low desert, these are actually winter crops planted in September or October.

Why does timing vary so much within Arizona?

Arizona's elevation ranges from 100 feet near Yuma to over 12,000 feet in the mountains. Phoenix at 1,100 feet and Flagstaff at 7,000 feet are essentially different climate zones.

What if I live in a frost-free area?

Parts of the low desert around Phoenix and Yuma rarely freeze. Focus on the fall-through-spring season and use shade cloth in the hottest months. Enter your zip code for personalized timing.

How does Plan My Garden create my schedule?

You enter your zip code, and we look up your local frost dates. Then based on the crops you pick, we calculate when to start seeds, transplant, and harvest — personalized to your location.