Arizona · zones 5b–10a
When to plant broccoli in Arizona.
Sow or transplant between Dec 15 to Jan 12 in a typical year, keyed to Arizona's median last frost around Feb 5. A second, fall sowing fits Aug 1 to Sep 10. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Broccoli dates for a typical Arizona season.
1 · Start indoors
Nov 3 to Dec 1
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Dec 15 to Jan 12
Keyed to the ~Feb 5 last frost. Sow 0.5" deep, 18" apart.
Fall round
Aug 1 to Sep 10
Counted back from the ~Nov 15 first frost.
Harvest
~60 days later
~1.2 lb per plant over ~3 weeks.
Arizona spans more than one climate: Zone 9 is the most common zone, but the state runs 5b to 10a. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
In Arizona: watch for
The pests that find broccoli here.
With about 283 frost-free days, broccoli spends longer in the ground here than in most of the country, which widens the window in which cabbage worms & loopers can find it. Scout weekly from midseason and act on the first signs.
Green caterpillars chewing ragged holes; green droppings.
Organic fix: Handpick, cover with netting, spray Bt.
Gray-green clusters tucked into the leaf folds.
Organic fix: Blast with water, then insecticidal soap.
Tiny holes peppering the young leaves.
Organic fix: Row cover from day one; diatomaceous earth.
Black rot
Yellow V-shaped wedges cutting in from the leaf edge, veins blackening inside.
Organic fix: Pull infected plants, water at the base, keep brassicas out of that bed 3 years.
Seedlings wilt, yellow and stall for no reason; white maggots tunnel the roots.
Organic fix: Row cover before the flies are up, when yellow rocket blooms; rotate the bed.
Your season math: Arizona gives broccoli about 283 frost-free days, and it needs roughly 60 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting broccoli in Arizona: questions
When should I plant broccoli in Arizona?+
In a typical Arizona year, sow broccoli or set out transplants between Dec 15 to Jan 12, keyed to the state's median last frost around Feb 5. There's also a fall window: Aug 1 to Sep 10. Your exact dates shift with your ZIP code and microclimate.
When do I start broccoli seeds indoors in Arizona?+
Start seeds inside about 6 weeks before set-out: roughly Nov 3 to Dec 1 for a typical Arizona season.
What USDA zone is Arizona?+
Arizona spans zones 5b–10a, mostly zone 9. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many broccoli plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.