Fountain Hills, AZ planting zone & frost dates
Fountain Hills is in USDA hardiness zone 9b. The last spring frost usually comes around January 6 and the first fall frost around December 28, for a growing season of about 356 days.
Planting calendar for Fountain Hills
Dates are counted from the average last spring frost (January 6) 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 11 – Nov 25 Transplant outdoors: Jan 13 – Jan 20 |
| Peppers | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Jan 20 – Jan 27 |
| Eggplant | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Jan 20 – Jan 27 |
| Broccoli | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Dec 9 – Dec 23 |
| Cabbage | Start seeds indoors: Oct 28 – Nov 11 Transplant outdoors: Dec 9 – Dec 23 |
| Onions (sets) | Plant outdoors: Dec 9 – Dec 23 |
| Peas | Sow outdoors: Nov 25 – Dec 9 |
| Spinach | Sow outdoors: Nov 25 – Dec 9 |
| Lettuce | Sow outdoors: Dec 9 – Dec 23 |
| Carrots | Sow outdoors: Dec 9 – Dec 23 |
| Potatoes | Plant outdoors: Dec 9 – Dec 23 |
| Beans | Sow outdoors: Jan 13 – Jan 20 |
| Sweet corn | Sow outdoors: Jan 13 – Jan 20 |
| Cucumbers | Sow outdoors: Jan 13 – Jan 20 |
| Squash & zucchini | Sow outdoors: Jan 13 – Jan 20 |
| Basil | Start seeds indoors: Nov 25 – Dec 9 Transplant outdoors: Jan 13 – Jan 20 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Nov 2 (8 weeks before the average first fall frost on Dec 28).
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 14 | Jan 6 | Feb 11 |
| First 32°F frost in fall is before | Jan 27 | Dec 28 | Dec 4 |
How to read it: in spring there is a 10% chance of a frost after February 11, so that is a safe date for tender plants. In fall there is a 10% chance of frost before December 4. A hard freeze (28°F) usually ends around January 9.
Hardiness zone by ZIP code in Fountain Hills
- 85268 zone 9b
- 85269 zone 9b
Nearby cities
- Scottsdale zone 10a, last frost Feb 13
- Mesa zone 9b, last frost Feb 13
- Paradise Valley zone 10a, last frost Jan 6
- Apache Junction zone 9b, last frost Feb 11
- Gilbert zone 9b, last frost Feb 13
- Tempe zone 10a, last frost Feb 13
- Tempe Junction zone 9b, last frost Feb 13
- Chandler zone 9b, last frost Feb 13
Questions
What growing zone is Fountain Hills, AZ?
Fountain Hills 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 Fountain Hills?
The average last spring frost (32°F) in Fountain Hills is January 6. There is still a 10% chance of frost until February 11.
When can I plant tomatoes in Fountain Hills?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Jan 13 – Jan 20. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Fountain Hills, AZ (USC00023190), 1.1 km (0.7 mi) from the city center, elevation 482 m, based on 21 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.