Walla Walla, WA planting zone & frost dates
Walla Walla is in USDA hardiness zone 7a. The last spring frost usually comes around March 27 and the first fall frost around October 31, for a growing season of about 219 days.
Planting calendar for Walla Walla
Dates are counted from the average last spring frost (March 27) 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: Jan 30 – Feb 13 Transplant outdoors: Apr 3 – Apr 10 |
| Peppers | Start seeds indoors: Jan 16 – Jan 30 Transplant outdoors: Apr 10 – Apr 17 |
| Eggplant | Start seeds indoors: Jan 16 – Jan 30 Transplant outdoors: Apr 10 – Apr 17 |
| Broccoli | Start seeds indoors: Jan 16 – Jan 30 Transplant outdoors: Feb 27 – Mar 13 |
| Cabbage | Start seeds indoors: Jan 16 – Jan 30 Transplant outdoors: Feb 27 – Mar 13 |
| Onions (sets) | Plant outdoors: Feb 27 – Mar 13 |
| Peas | Sow outdoors: Feb 13 – Feb 27 |
| Spinach | Sow outdoors: Feb 13 – Feb 27 |
| Lettuce | Sow outdoors: Feb 27 – Mar 13 |
| Carrots | Sow outdoors: Feb 27 – Mar 13 |
| Potatoes | Plant outdoors: Feb 27 – Mar 13 |
| Beans | Sow outdoors: Apr 3 – Apr 10 |
| Sweet corn | Sow outdoors: Apr 3 – Apr 10 |
| Cucumbers | Sow outdoors: Apr 3 – Apr 10 |
| Squash & zucchini | Sow outdoors: Apr 3 – Apr 10 |
| Basil | Start seeds indoors: Feb 13 – Feb 27 Transplant outdoors: Apr 3 – Apr 10 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 5 (8 weeks before the average first fall frost on Oct 31).
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 | Mar 3 | Mar 27 | Apr 22 |
| First 32°F frost in fall is before | Nov 17 | Oct 31 | Oct 15 |
How to read it: in spring there is a 10% chance of a frost after April 22, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 15. A hard freeze (28°F) usually ends around March 4.
Hardiness zone by ZIP code in Walla Walla
- 99362 zone 7a
Nearby cities
- Pasco zone 7b, last frost Mar 28
- Kennewick zone 7b, last frost Mar 28
- Richland zone 7b, last frost Apr 6
- West Richland zone 7b, last frost Apr 6
- Pullman zone 6b, last frost May 6
- Moses Lake zone 7a, last frost Apr 27
- Grandview zone 7b, last frost May 1
- Cheney zone 6b, last frost May 30
Questions
What growing zone is Walla Walla, WA?
Walla Walla 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 Walla Walla?
The average last spring frost (32°F) in Walla Walla is March 27. There is still a 10% chance of frost until April 22.
When can I plant tomatoes in Walla Walla?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 3 – Apr 10. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Walla Walla Rgnl Ap, WA (USW00024160), 5.5 km (3.4 mi) from the city center, elevation 355 m, based on 25 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.