When to Plant Marigolds in Arizona
The ultimate companion plant. Marigolds repel pests, attract pollinators, and add cheerful color all season long.
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 |
Marigolds 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 Marigolds in Arizona
Marigolds in Arizona's Climate
Marigolds can struggle in peak subtropical summer humidity — root rot and fungal diseases are more common than in drier climates. Plant during the cooler months (October through April) for best results. Their nematode-suppressing properties are extremely valuable in Florida's nematode-heavy sandy soils.
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 marigolds 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. Marigolds 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 marigolds — transplant timing shifts by several weeks across the state.
Growing Tips
French marigolds are best for pest control in vegetable gardens. Deadhead spent flowers to keep them blooming until frost.
Companion Planting
Plant marigolds alongside these companions for better growth:
The Bottom Line
Last reviewed: March 29, 2026