El Mirage, AZ planting zone & frost dates
El Mirage is in USDA hardiness zone 9b. The last spring frost usually comes around January 20 and the first fall frost around December 15, for a growing season of about 331 days.
Planting calendar for El Mirage
Dates are counted from the average last spring frost (January 20) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Nov 25 – Dec 9 Transplant outdoors: Jan 27 – Feb 3 |
| Peppers | Start seeds indoors: Nov 11 – Nov 25 Transplant outdoors: Feb 3 – Feb 10 |
| Eggplant | Start seeds indoors: Nov 11 – Nov 25 Transplant outdoors: Feb 3 – Feb 10 |
| Broccoli | Start seeds indoors: Nov 11 – Nov 25 Transplant outdoors: Dec 23 – Jan 6 |
| Cabbage | Start seeds indoors: Nov 11 – Nov 25 Transplant outdoors: Dec 23 – Jan 6 |
| Onions (sets) | Plant outdoors: Dec 23 – Jan 6 |
| Peas | Sow outdoors: Dec 9 – Dec 23 |
| Spinach | Sow outdoors: Dec 9 – Dec 23 |
| Lettuce | Sow outdoors: Dec 23 – Jan 6 |
| Carrots | Sow outdoors: Dec 23 – Jan 6 |
| Potatoes | Plant outdoors: Dec 23 – Jan 6 |
| Beans | Sow outdoors: Jan 27 – Feb 3 |
| Sweet corn | Sow outdoors: Jan 27 – Feb 3 |
| Cucumbers | Sow outdoors: Jan 27 – Feb 3 |
| Squash & zucchini | Sow outdoors: Jan 27 – Feb 3 |
| Basil | Start seeds indoors: Dec 9 – Dec 23 Transplant outdoors: Jan 27 – Feb 3 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 20 (8 weeks before the average first fall frost on Dec 15).
Useful for zone 9b gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Shade cloth — for hot summers
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Dec 23 | Jan 20 | Feb 18 |
| First 32°F frost in fall is before | Jan 7 | Dec 15 | Nov 28 |
How to read it: in spring there is a 10% chance of a frost after February 18, so that is a safe date for tender plants. In fall there is a 10% chance of frost before November 28. A hard freeze (28°F) usually ends around January 3.
Hardiness zone by ZIP code in El Mirage
- 85335 zone 9b
Nearby cities
Questions
What growing zone is El Mirage, AZ?
El Mirage is in USDA Plant Hardiness Zone 9b (average extreme winter low 25°F to 30°F), according to the USDA 2023 map.
When is the last frost in El Mirage?
The average last spring frost (32°F) in El Mirage is January 20. There is still a 10% chance of frost until February 18.
When can I plant tomatoes in El Mirage?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Jan 27 – Feb 3. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Youngtown, AZ (USC00029634), 2.9 km (1.8 mi) from the city center, elevation 346 m, based on 29 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.