Coolidge, AZ planting zone & frost dates
Coolidge is in USDA hardiness zone 9a. The last spring frost usually comes around February 17 and the first fall frost around November 29, for a growing season of about 284 days.
Planting calendar for Coolidge
Dates are counted from the average last spring frost (February 17) 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: Dec 23 – Jan 6 Transplant outdoors: Feb 24 – Mar 3 |
| Peppers | Start seeds indoors: Dec 9 – Dec 23 Transplant outdoors: Mar 3 – Mar 10 |
| Eggplant | Start seeds indoors: Dec 9 – Dec 23 Transplant outdoors: Mar 3 – Mar 10 |
| Broccoli | Start seeds indoors: Dec 9 – Dec 23 Transplant outdoors: Jan 20 – Feb 3 |
| Cabbage | Start seeds indoors: Dec 9 – Dec 23 Transplant outdoors: Jan 20 – Feb 3 |
| Onions (sets) | Plant outdoors: Jan 20 – Feb 3 |
| Peas | Sow outdoors: Jan 6 – Jan 20 |
| Spinach | Sow outdoors: Jan 6 – Jan 20 |
| Lettuce | Sow outdoors: Jan 20 – Feb 3 |
| Carrots | Sow outdoors: Jan 20 – Feb 3 |
| Potatoes | Plant outdoors: Jan 20 – Feb 3 |
| Beans | Sow outdoors: Feb 24 – Mar 3 |
| Sweet corn | Sow outdoors: Feb 24 – Mar 3 |
| Cucumbers | Sow outdoors: Feb 24 – Mar 3 |
| Squash & zucchini | Sow outdoors: Feb 24 – Mar 3 |
| Basil | Start seeds indoors: Jan 6 – Jan 20 Transplant outdoors: Feb 24 – Mar 3 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 4 (8 weeks before the average first fall frost on Nov 29).
Useful for zone 9a 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 | Jan 22 | Feb 17 | Mar 8 |
| First 32°F frost in fall is before | Dec 15 | Nov 29 | Nov 12 |
How to read it: in spring there is a 10% chance of a frost after March 8, so that is a safe date for tender plants. In fall there is a 10% chance of frost before November 12. A hard freeze (28°F) usually ends around January 26.
Hardiness zone by ZIP code in Coolidge
- 85128 zone 9a
Nearby cities
- Florence zone 9a, last frost Jan 30
- San Tan Valley zone 9b, last frost Feb 1
- Eloy zone 9a, last frost Feb 24
- Casa Grande zone 9a, last frost Feb 5
- Arizona City zone 9a, last frost Feb 28
- Queen Creek zone 9b, last frost Feb 1
- Gold Camp zone 9b, last frost Jan 18
- Gold Canyon zone 9b, last frost Feb 11
Questions
What growing zone is Coolidge, AZ?
Coolidge is in USDA Plant Hardiness Zone 9a (average extreme winter low 20°F to 25°F), according to the USDA 2023 map.
When is the last frost in Coolidge?
The average last spring frost (32°F) in Coolidge is February 17. There is still a 10% chance of frost until March 8.
When can I plant tomatoes in Coolidge?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Feb 24 – Mar 3. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Casa Grande Nm, AZ (USC00021314), 2.6 km (1.6 mi) from the city center, elevation 432 m, based on 26 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.