Pullman, WA planting zone & frost dates
Pullman is in USDA hardiness zone 6b. The last spring frost usually comes around May 6 and the first fall frost around September 29, for a growing season of about 143 days.
Planting calendar for Pullman
Dates are counted from the average last spring frost (May 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: Mar 11 – Mar 25 Transplant outdoors: May 13 – May 20 |
| Peppers | Start seeds indoors: Feb 25 – Mar 11 Transplant outdoors: May 20 – May 27 |
| Eggplant | Start seeds indoors: Feb 25 – Mar 11 Transplant outdoors: May 20 – May 27 |
| Broccoli | Start seeds indoors: Feb 25 – Mar 11 Transplant outdoors: Apr 8 – Apr 22 |
| Cabbage | Start seeds indoors: Feb 25 – Mar 11 Transplant outdoors: Apr 8 – Apr 22 |
| Onions (sets) | Plant outdoors: Apr 8 – Apr 22 |
| Peas | Sow outdoors: Mar 25 – Apr 8 |
| Spinach | Sow outdoors: Mar 25 – Apr 8 |
| Lettuce | Sow outdoors: Apr 8 – Apr 22 |
| Carrots | Sow outdoors: Apr 8 – Apr 22 |
| Potatoes | Plant outdoors: Apr 8 – Apr 22 |
| Beans | Sow outdoors: May 13 – May 20 |
| Sweet corn | Sow outdoors: May 13 – May 20 |
| Cucumbers | Sow outdoors: May 13 – May 20 |
| Squash & zucchini | Sow outdoors: May 13 – May 20 |
| Basil | Start seeds indoors: Mar 25 – Apr 8 Transplant outdoors: May 13 – May 20 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 4 (8 weeks before the average first fall frost on Sep 29).
Useful for zone 6b 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
- Cold frame / mini greenhouse — adds weeks to a short season
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 22 | May 6 | May 25 |
| First 32°F frost in fall is before | Oct 15 | Sep 29 | Sep 9 |
How to read it: in spring there is a 10% chance of a frost after May 25, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 9. A hard freeze (28°F) usually ends around April 19.
Hardiness zone by ZIP code in Pullman
- 99163 zone 6b
Nearby cities
- Cheney zone 6b, last frost May 30
- Spokane Valley zone 7a, last frost Apr 26
- Spokane zone 7a, last frost Apr 26
- Walla Walla zone 7a, last frost Mar 27
- Pasco zone 7b, last frost Mar 28
- Kennewick zone 7b, last frost Mar 28
- Moses Lake zone 7a, last frost Apr 27
- Richland zone 7b, last frost Apr 6
Questions
What growing zone is Pullman, WA?
Pullman is in USDA Plant Hardiness Zone 6b (average extreme winter low -5°F to 0°F), according to the USDA 2023 map.
When is the last frost in Pullman?
The average last spring frost (32°F) in Pullman is May 6. There is still a 10% chance of frost until May 25.
When can I plant tomatoes in Pullman?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 13 – May 20. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Pullman 2 Nw, WA (USC00456789), 3.3 km (2.0 mi) from the city center, elevation 767 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.