Arizona · zones 5b–10a
When to plant basil in Arizona.
Sow or transplant between Feb 26 to May 14 in a typical year, keyed to Arizona's median last frost around Feb 5. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Basil dates for a typical Arizona season.
1 · Start indoors
Jan 15 to Apr 2
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Feb 26 to May 14
Keyed to the ~Feb 5 last frost. Sow 0.25" deep, 8" apart.
Harvest
~40 days later
~0.5 lb per plant over ~12 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 basil here.
With about 283 frost-free days, basil spends longer in the ground here than in most of the country, which widens the window in which aphids can find it. Scout weekly from midseason and act on the first signs.
Fine webbing and pale stippling in hot, dry spells.
Organic fix: Spray the undersides with water, then insecticidal soap or neem.
Yellowing with gray fuzz underneath, or white powder on top.
Organic fix: Space for airflow, water at the base, spray neem.
Your season math: Arizona gives basil about 283 frost-free days, and it needs roughly 40 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting basil in Arizona: questions
When should I plant basil in Arizona?+
In a typical Arizona year, sow basil or set out transplants between Feb 26 to May 14, keyed to the state's median last frost around Feb 5. Your exact dates shift with your ZIP code and microclimate.
When do I start basil seeds indoors in Arizona?+
Start seeds inside about 6 weeks before set-out: roughly Jan 15 to Apr 2 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 basil 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.