Nampa, ID planting zone & frost dates
Nampa is in USDA hardiness zone 7a. The last spring frost usually comes around April 29 and the first fall frost around October 13, for a growing season of about 164 days.
Planting calendar for Nampa
Dates are counted from the average last spring frost (April 29) 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: Mar 4 – Mar 18 Transplant outdoors: May 6 – May 13 |
| Peppers | Start seeds indoors: Feb 18 – Mar 4 Transplant outdoors: May 13 – May 20 |
| Eggplant | Start seeds indoors: Feb 18 – Mar 4 Transplant outdoors: May 13 – May 20 |
| Broccoli | Start seeds indoors: Feb 18 – Mar 4 Transplant outdoors: Apr 1 – Apr 15 |
| Cabbage | Start seeds indoors: Feb 18 – Mar 4 Transplant outdoors: Apr 1 – Apr 15 |
| Onions (sets) | Plant outdoors: Apr 1 – Apr 15 |
| Peas | Sow outdoors: Mar 18 – Apr 1 |
| Spinach | Sow outdoors: Mar 18 – Apr 1 |
| Lettuce | Sow outdoors: Apr 1 – Apr 15 |
| Carrots | Sow outdoors: Apr 1 – Apr 15 |
| Potatoes | Plant outdoors: Apr 1 – Apr 15 |
| Beans | Sow outdoors: May 6 – May 13 |
| Sweet corn | Sow outdoors: May 6 – May 13 |
| Cucumbers | Sow outdoors: May 6 – May 13 |
| Squash & zucchini | Sow outdoors: May 6 – May 13 |
| Basil | Start seeds indoors: Mar 18 – Apr 1 Transplant outdoors: May 6 – May 13 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 18 (8 weeks before the average first fall frost on Oct 13).
Useful for zone 7a 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
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 15 | Apr 29 | May 18 |
| First 32°F frost in fall is before | Oct 28 | Oct 13 | Sep 29 |
How to read it: in spring there is a 10% chance of a frost after May 18, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 29. A hard freeze (28°F) usually ends around April 11.
Hardiness zone by ZIP code in Nampa
- 83651 zone 7a
- 83652 zone 7a
- 83653 zone 7a
- 83686 zone 7a
- 83687 zone 7a
Nearby cities
- Kuna zone 7a, last frost Apr 24
- Caldwell zone 7a, last frost Apr 23
- Meridian zone 7a, last frost Apr 24
- Eagle zone 7a, last frost Apr 24
- Eagle Foothills zone 7a, last frost Apr 30
- Garden City zone 7a, last frost Apr 24
- Boise zone 7a, last frost Apr 24
- Jerome zone 6b, last frost May 2
Questions
What growing zone is Nampa, ID?
Nampa is in USDA Plant Hardiness Zone 7a (average extreme winter low 0°F to 5°F), according to the USDA 2023 map.
When is the last frost in Nampa?
The average last spring frost (32°F) in Nampa is April 29. There is still a 10% chance of frost until May 18.
When can I plant tomatoes in Nampa?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 6 – May 13. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Nampa Sugar Factory, ID (USC00106305), 7.1 km (4.4 mi) from the city center, elevation 753 m, based on 22 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.