When to Plant Broccoli in Arizona
Published: April 21, 2026
Arizona gardeners in Zone 9b enjoy an extended 50-week growing season for broccoli. Cool-season crops like broccoli do best in fall, winter, and early spring in Arizona — the hot summers bolt these plants before they can be harvested. This guide gives exact dates for Arizona based on your local frost calendar.
Broccoli Planting Dates for Arizona
| Start seeds indoors | December 4–11 |
| Last frost (average) | January 15 |
| Transplant outdoors | December 18–28 |
| Direct sow outdoors | December 18–28 |
| Expect first harvest | February 16 – March 8 |
| Fall crop start | October 22–November 1 |
| Fall harvest | December 21 |
| First fall frost (average) | December 31 |
Dates above assume Zone 9b, the most common zone in Arizona. Gardeners in cooler San Tan Valley (Zone 7b) plant 1–2 weeks later; warmer Tucson (Zone 9a) can plant 1–2 weeks earlier.
Growing Broccoli in Arizona's Climate
Arizona's warm Zone 9b climate makes broccoli a fall, winter, and early spring crop rather than a summer one. The cool-season window runs roughly October through April in Arizona — plant outside this window and the broccoli will bolt (send up a flower stalk and turn bitter) before it produces a harvestable crop.
Succession planting stretches the broccoli harvest window. Sow small amounts every two weeks from October through February — you will have staggered harvests rather than a single wave to process all at once. Bolt-resistant varieties extend the usable window an extra three to four weeks into warming weather.
Common broccoli pests to watch for in Arizona include Cabbage Worm and Cabbage Looper. The first line of defense is companion planting: Onion and Garlic planted nearby discourage several of these pests by confusing host-plant identification or repelling adults before they can lay eggs. Weekly garden walks in the early morning catch problems when they're still manageable.
Broccoli Garden Calendar for Arizona
| Month | Task | Notes |
|---|---|---|
| January | Harden off seedlings | Set seedlings outdoors 1–2 hours daily, increasing gradually |
| February | First harvest window opens | Broccoli begins producing 60–80 days after transplant |
| March | — | Off-season |
| April | — | Off-season |
| May ← | Watch for bolting | Harvest promptly; spring heat arrives quickly |
| June | — | Off-season |
| July | — | Off-season |
| August | — | Off-season |
| September | — | Off-season |
| October | Fall crop planting | Transplant or direct sow for fall harvest before frost |
| November | — | Off-season |
| December | Transplant outdoors | Soil temp must be 40°F+; nighttime lows above 50°F |
Broccoli Growing Tips for Arizona Gardeners
- •For spring: start indoors 6 weeks before last frost and transplant outdoors 4 weeks before last frost.
- •For fall: start indoors in summer — count 10 weeks back from your first fall frost date.
- •Arizona's cool-season broccoli plants best in October, November, and December for winter and early spring harvest. Spring plantings bolt before producing a harvestable crop.
- •Harvest heads before any yellow flowers open — once flowers show, flavor declines quickly.
Companion Planting for Broccoli in Arizona
In Arizona's warm climate, planting broccoli with Onion and Garlic helps deter pests and improve soil. Avoid planting near Tomato and Pepper, which inhibit broccoli growth through root chemistry or shared pest pressure. See the full broccoli companion planting guide for the complete list.
Broccoli Planting Dates by City in Arizona
Top cities in Arizona — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant broccoli in Arizona?
In Arizona (Zone 9b), start broccoli seeds indoors around December 4–11 and transplant outdoors around December 18–28 — 4 weeks before the state's average last frost of January 15.
What is the last frost date in Arizona?
Arizona's average last frost date is January 15 in the state's most common Zone 9b. Frost dates vary by city — higher elevations and northern counties run 1 to 3 weeks later than the state average. See the city list below for city-level frost dates.
Can I grow broccoli year-round in Arizona?
broccoli is a cool-season crop in Arizona, with spring and fall windows. Summer heat bolts the plants before they can produce a harvestable crop. Succession planting every 2–3 weeks stretches the harvest window.
What broccoli varieties grow best in Arizona?
For Arizona's Zone 9b, Calabrese and Packman resist bolting in brief warm spells during the cool-season window.
When do I start broccoli seeds indoors in Arizona?
Start broccoli seeds indoors in Arizona around December 4–11, which is 6 weeks before the state's average last frost of January 15. Use grow lights and keep soil temperatures at 70–75°F for fastest germination.