When to Plant Basil in Arizona
The king of herbs. Basil and tomatoes are best friends in the garden and in the kitchen.
The Short Answer
Arizona Frost Dates
Your planting dates depend on which part of Arizona you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern Arizona (Flagstaff) | 4b, 5a, 5b, 6a | May 15 - Jun 5 | Sep 15 - Oct 10 |
| Central Arizona (Phoenix) | 9a, 9b, 10a | Jan 15 - Feb 10 | Dec 1 - Dec 20 |
| Southern Arizona (Tucson) | 8b, 9a, 9b | Feb 1 - Feb 25 | Nov 20 - Dec 15 |
Basil Planting Schedule for Arizona
Northern Arizona (Flagstaff) (Zones 4b, 5a, 5b, 6a)
Average last frost: May 15 - Jun 5 · Average first frost: Sep 15 - Oct 10
Central Arizona (Phoenix) (Zones 9a, 9b, 10a)
Average last frost: Jan 15 - Feb 10 · Average first frost: Dec 1 - Dec 20
Southern Arizona (Tucson) (Zones 8b, 9a, 9b)
Average last frost: Feb 1 - Feb 25 · Average first frost: Nov 20 - Dec 15
Growing Basil in Arizona
Basil in Arizona's Climate
Basil grows nearly year-round in subtropical zones. The challenge isn't cold but humidity — downy mildew thrives in warm, wet conditions. Choose resistant varieties and provide good air circulation. In south Florida and Hawaii, basil is perennial — plants survive winter and continue producing for years.
Soil Considerations for Arizona
Alkaline, mineral-rich desert soils. Low organic matter. Heavy amendment with compost essential. Caliche layers may need to be broken. Make sure soil has warmed to at least 60°F before planting basil outside.
Arizona Climate & Growing Season
Extreme heat in summer lowlands. Two planting seasons in Phoenix — spring and fall (summer is too hot). High elevation has traditional cold-climate seasons. Basil cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.
Growing season length varies across Arizona: Northern Arizona (Flagstaff) (4b, 5a, 5b, 6a) has a last frost around May 15 - Jun 5, while Southern Arizona (Tucson) (8b, 9a, 9b) sees frost end around Feb 1 - Feb 25. This difference matters for basil — transplant timing shifts by several weeks across the state.
Growing Tips
Pinch off flower buds to keep leaves producing. Harvest from the top down, cutting just above a leaf pair. Succession plant for season-long supply.
Companion Planting
Plant basil alongside these companions for better growth:
Keep basil away from:
The Bottom Line
Last reviewed: March 29, 2026