Frost Dates for Walla Walla, WA 99362
Last spring frost April 27 · First fall frost October 10 · 166 frost-free days · USDA Zone 7a
ZIP 99362 has about 42,900 people.
Moderate season: 166 frost-free days. Spring frost risk spans April 6–May 19 (43 days). Fall frost risk spans September 25–October 24 (29 days).
Frost probability for 99362
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 19 | April 27 | April 6 |
| Fall (first frost) | September 25 | October 10 | October 24 |
Dates come from NOAA 1971–2000 freeze probabilities at DAYTON 1 WSW (34.8 km away); the 50% date is the median year.
Which crops fit a 166-day season in Walla Walla
In Walla Walla (166 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 23 | May 11–May 18 | 124 | fits: 80 days to maturity, 124 available after May 11. | Jun 10 |
| Pepper | Mar 16 | May 11–May 18 | 124 | fits: 75 days to maturity, 124 available after May 11. | Jun 15 |
| Lettuce | Mar 2 | Mar 30–Apr 6 | 201 | two-plantings: Plant Mar 30 and again by Aug 19; both mature before Oct 17. | Aug 19 |
| Carrots | — | Apr 6–Apr 13 | 208 | fits: 70 days to maturity, 208 available after Apr 6. | Aug 8 |
| Cucumber | Apr 6 | May 11–May 18 | 138 | two-plantings: Plant May 11 and again by Jul 14; both mature before Sep 26. | Jul 14 |
| Beans | — | May 4–May 18 | 152 | two-plantings: Plant May 4 and again by Jul 21; both mature before Oct 3. | Jul 21 |
| Peas | — | Mar 2–May 11 | 229 | fits: 65 days to maturity, 229 available after Mar 2. | Jul 30 |
| Zucchini | Apr 13 | May 11–May 18 | 138 | two-plantings: Plant May 11 and again by Jul 19; both mature before Sep 26. | Jul 19 |
| Onion | Feb 2 | Mar 30–Apr 13 | 201 | fits: 100 days to maturity, 201 available after Mar 30. | — |
| Spinach | — | Mar 2–Apr 20 | 243 | two-plantings: Plant Mar 2 and again by Sep 7; both mature before Oct 31. | Sep 7 |
| Kale | Feb 16 | Mar 30–Apr 13 | 215 | two-plantings: Plant Mar 30 and again by Aug 23; both mature before Oct 31. | Aug 23 |
| Broccoli | Mar 2 | Mar 30–Apr 13 | 201 | fits: 80 days to maturity, 201 available after Mar 30. | Jul 15 |
| Cabbage | Mar 2 | Mar 30–Apr 13 | 215 | fits: 70 days to maturity, 215 available after Mar 30. | Aug 8 |
| Radish | — | Mar 2–May 25 | 229 | two-plantings: Plant Mar 2 and again by Sep 8; both mature before Oct 17. | Sep 8 |
| Beets | — | Mar 2–May 25 | 229 | two-plantings: Plant Mar 2 and again by Aug 9; both mature before Oct 17. | Aug 9 |
| Potatoes | — | Apr 13–Apr 20 | 187 | fits: 90 days to maturity, 187 available after Apr 13. | — |
| Garlic | — | Oct 10 | 271 | overwinter: Plant Oct 10 to Oct 31; harvest the following summer. | Oct 31 |
| Strawberry | — | Mar 23–May 18 | 222 | perennial: A perennial: plant Mar 23; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 30 | May 4–May 11 | 138 | fits: 75 days to maturity, 138 available after May 4. | Jun 22 |
| Pumpkin | Apr 13 | May 11–May 11 | 131 | fits: 100 days to maturity, 131 available after May 11. | May 28 |
| Cauliflower | Mar 16 | Apr 20–May 4 | 180 | fits: 75 days to maturity, 180 available after Apr 20. | Jul 20 |
| Swiss Chard | Mar 2 | Apr 13–Apr 13 | 187 | two-plantings: Plant Apr 13 and again by Aug 9; both mature before Oct 17. | Aug 9 |
| Arugula | — | Mar 2–May 25 | 243 | two-plantings: Plant Mar 2 and again by Sep 7; both mature before Oct 31. | Sep 7 |
| Brussel Sprouts | Mar 2 | Mar 30–Apr 13 | 215 | fits: 100 days to maturity, 215 available after Mar 30. | Jul 9 |
| Butternut Squash | Apr 13 | May 11–May 18 | 131 | fits: 100 days to maturity, 131 available after May 11. | May 28 |
| Eggplant | Mar 9 | May 11–May 18 | 124 | fits: 70 days to maturity, 124 available after May 11. | Jun 20 |
| Okra | Mar 30 | May 4–May 11 | 145 | two-plantings: Plant May 4 and again by Jul 19; both mature before Sep 26. | Jul 19 |
| Basil | Mar 23 | May 18–May 18 | 131 | fits: 60 days to maturity, 131 available after May 18. | Jul 14 |
| Cilantro | — | Mar 30–Apr 20 | 201 | two-plantings: Plant Mar 30 and again by Aug 14; both mature before Oct 17. | Aug 14 |
| Parsley | Feb 16 | May 4–May 11 | 166 | fits: 70 days to maturity, 166 available after May 4. | Jul 25 |
| Celery | Feb 16 | May 4–May 18 | 166 | fits: 120 days to maturity, 166 available after May 4. | Jun 5 |
| Scallions | Feb 16 | Mar 30–Apr 13 | 215 | two-plantings: Plant Mar 30 and again by Aug 18; both mature before Oct 31. | Aug 18 |
| Turnip | — | Mar 30–Apr 13 | 215 | two-plantings: Plant Mar 30 and again by Aug 28; both mature before Oct 31. | Aug 28 |
| Kohlrabi | — | Mar 16–Mar 30 | 229 | two-plantings: Plant Mar 16 and again by Aug 23; both mature before Oct 31. | Aug 23 |
| Bok Choy | Mar 30 | Apr 20–Apr 27 | 180 | two-plantings: Plant Apr 20 and again by Aug 19; both mature before Oct 17. | Aug 19 |
| Collards | Feb 16 | Mar 30–Apr 13 | 215 | two-plantings: Plant Mar 30 and again by Aug 18; both mature before Oct 31. | Aug 18 |
| Cantaloupe | Apr 13 | May 11–May 18 | 124 | fits: 85 days to maturity, 124 available after May 11. | Jun 5 |
| Chives | Feb 2 | May 4–May 11 | 180 | fits: 90 days to maturity, 180 available after May 4. | — |
| Dill | — | Mar 2–May 25 | 229 | two-plantings: Plant Mar 2 and again by Aug 9; both mature before Oct 17. | Aug 9 |
| Oregano | Feb 16 | May 4–May 11 | 180 | fits: 80 days to maturity, 180 available after May 4. | — |
| Rosemary | Feb 2 | May 4–May 11 | 166 | fits: 80 days to maturity, 166 available after May 4. | — |
| Sage | Mar 2 | May 4–May 11 | 180 | fits: 75 days to maturity, 180 available after May 4. | — |
| Thyme | Feb 16 | May 4–May 11 | 180 | fits: 90 days to maturity, 180 available after May 4. | — |
| Calendula | Mar 16 | Apr 13–Apr 27 | 187 | two-plantings: Plant Apr 13 and again by Aug 14; both mature before Oct 17. | Aug 14 |
| Cosmos | Mar 30 | Apr 27–May 11 | 152 | two-plantings: Plant Apr 27 and again by Jul 14; both mature before Sep 26. | Jul 14 |
| Lavender | Feb 2 | Apr 27–May 11 | 187 | fits: 90 days to maturity, 187 available after Apr 27. | — |
| Marigolds | Mar 16 | Apr 27–May 4 | 152 | two-plantings: Plant Apr 27 and again by Jul 24; both mature before Sep 26. | Jul 24 |
| Melons | Apr 13 | May 11–May 18 | 124 | fits: 85 days to maturity, 124 available after May 11. | Jun 5 |
| Mint | — | Apr 27–May 11 | 187 | fits: 90 days to maturity, 187 available after Apr 27. | — |
| Nasturtiums | Mar 30 | Apr 27–May 4 | 152 | two-plantings: Plant Apr 27 and again by Jul 19; both mature before Sep 26. | Jul 19 |
| Pole Beans | — | May 4–May 18 | 145 | fits: 65 days to maturity, 145 available after May 4. | Jul 9 |
| Spaghetti Squash | Apr 13 | May 11–May 18 | 131 | fits: 90 days to maturity, 131 available after May 11. | Jun 7 |
| Sunflowers | — | Apr 27–May 11 | 152 | fits: 70 days to maturity, 152 available after Apr 27. | Jul 4 |
| Tomatillos | Mar 2 | May 4–May 11 | 131 | fits: 75 days to maturity, 131 available after May 4. | Jun 15 |
| Watermelon | Apr 13 | May 4–May 11 | 131 | fits: 80 days to maturity, 131 available after May 4. | Jun 10 |
| Yellow Squash | Apr 13 | May 11–May 18 | 138 | two-plantings: Plant May 11 and again by Jul 19; both mature before Sep 26. | Jul 19 |
| Zinnias | Mar 30 | Apr 27–May 11 | 152 | two-plantings: Plant Apr 27 and again by Jul 14; both mature before Sep 26. | Jul 14 |
Month by month in Walla Walla
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 2), Lavender (Feb 2), Onion (Feb 2), Rosemary (Feb 2), Celery (Feb 16), Collards (Feb 16), +5 more. |
| March | Start indoors: Broccoli (Mar 2), Brussel Sprouts (Mar 2), Cabbage (Mar 2), Lettuce (Mar 2), Sage (Mar 2), Swiss Chard (Mar 2), +14 more. Direct sow from: Arugula (Mar 2), Beets (Mar 2), Dill (Mar 2), Peas (Mar 2), Radish (Mar 2), Spinach (Mar 2), +3 more. Transplant from: Broccoli (Mar 30), Brussel Sprouts (Mar 30), Cabbage (Mar 30), Collards (Mar 30), Kale (Mar 30), Lettuce (Mar 30), +2 more. Plant: Strawberry (Mar 23). |
| April | Start indoors: Cucumber (Apr 6), Butternut Squash (Apr 13), Cantaloupe (Apr 13), Melons (Apr 13), Pumpkin (Apr 13), Spaghetti Squash (Apr 13), +3 more. Direct sow from: Carrots (Apr 6), Potatoes (Apr 13), Sunflowers (Apr 27). Transplant from: Calendula (Apr 13), Swiss Chard (Apr 13), Bok Choy (Apr 20), Cauliflower (Apr 20), Cosmos (Apr 27), Lavender (Apr 27), +4 more. Last frost around April 27. |
| May | Direct sow from: Beans (May 4), Pole Beans (May 4). Transplant from: Celery (May 4), Chives (May 4), Corn (May 4), Okra (May 4), Oregano (May 4), Parsley (May 4), +17 more. Last sowing dates: Butternut Squash (May 28), Pumpkin (May 28). |
| June | Last sowing dates: Cantaloupe (Jun 5), Celery (Jun 5), Melons (Jun 5), Spaghetti Squash (Jun 7), Tomato (Jun 10), Watermelon (Jun 10), +4 more. |
| July | Last sowing dates: Sunflowers (Jul 4), Brussel Sprouts (Jul 9), Pole Beans (Jul 9), Basil (Jul 14), Cosmos (Jul 14), Cucumber (Jul 14), +11 more. |
| August | Last sowing dates: Cabbage (Aug 8), Carrots (Aug 8), Beets (Aug 9), Dill (Aug 9), Swiss Chard (Aug 9), Calendula (Aug 14), +8 more. |
| September | Last sowing dates: Arugula (Sep 7), Spinach (Sep 7), Radish (Sep 8). |
| October | Direct sow from: Garlic (Oct 10). First frost around October 10. Last sowing dates: Garlic (Oct 31). |
| November | Harvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year. |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Walla Walla, WA (ZIP 99362)?
The median last spring frost date for Walla Walla, WA (ZIP code 99362) is around April 27. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before April 6; one in ten it runs past May 19.
What is the first fall frost date in Walla Walla, WA?
The median first fall frost date for Walla Walla, WA is around October 10. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around September 25 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Walla Walla, WA?
The frost-free growing season in Walla Walla is about 166 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Walla Walla (166 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Walla Walla, WA?
Walla Walla, WA is in USDA hardiness zone 7a (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Walla Walla, WA?
Start tomatoes indoors Mar 23 and plant out May 11 in Walla Walla. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Walla Walla?
Two: plant Mar 30 and again by Aug 19; both mature before Oct 17.
When do I plant garlic in Walla Walla?
Oct 10 to Oct 31; it overwinters and is ready the following summer.
Which nearby ZIP has a longer season?
Pasco (ZIP 99301) has 191 frost-free days, 25 more than Walla Walla (ZIP 99362). See Pasco ZIP 99301 frost dates
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