Frost Dates for Hermiston, OR 97838
Last spring frost April 8 · First fall frost October 21 · 196 frost-free days · USDA Zone 7b
ZIP 97838 has about 28,500 people.
Long season: 196 frost-free days. Spring frost risk spans March 18–April 29 (42 days). Fall frost risk spans October 5–November 6 (32 days).
Frost probability for 97838
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | April 29 | April 8 | March 18 |
| Fall (first frost) | October 5 | October 21 | November 6 |
Dates come from NOAA 1971–2000 freeze probabilities at KENNEWICK (42.4 km away); the 50% date is the median year.
Which crops fit a 196-day season in Hermiston
In Hermiston (196 frost-free days, a long season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 4 | Apr 22–Apr 29 | 154 | fits: 80 days to maturity, 154 available after Apr 22. | Jun 21 |
| Pepper | Feb 25 | Apr 22–Apr 29 | 154 | fits: 75 days to maturity, 154 available after Apr 22. | Jun 26 |
| Lettuce | Feb 11 | Mar 11–Mar 18 | 231 | two-plantings: Plant Mar 11 and again by Aug 30; both mature before Oct 28. | Aug 30 |
| Carrots | — | Mar 18–Mar 25 | 238 | fits: 70 days to maturity, 238 available after Mar 18. | Aug 19 |
| Cucumber | Mar 18 | Apr 22–Apr 29 | 168 | two-plantings: Plant Apr 22 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Beans | — | Apr 15–Apr 29 | 182 | two-plantings: Plant Apr 15 and again by Aug 1; both mature before Oct 14. | Aug 1 |
| Peas | — | Feb 11–Apr 22 | 259 | fits: 65 days to maturity, 259 available after Feb 11. | Aug 10 |
| Zucchini | Mar 25 | Apr 22–Apr 29 | 168 | two-plantings: Plant Apr 22 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Onion | Jan 14 | Mar 11–Mar 25 | 231 | fits: 100 days to maturity, 231 available after Mar 11. | — |
| Spinach | — | Feb 11–Apr 1 | 273 | two-plantings: Plant Feb 11 and again by Sep 18; both mature before Nov 11. | Sep 18 |
| Kale | Jan 28 | Mar 11–Mar 25 | 245 | two-plantings: Plant Mar 11 and again by Sep 3; both mature before Nov 11. | Sep 3 |
| Broccoli | Feb 11 | Mar 11–Mar 25 | 231 | fits: 80 days to maturity, 231 available after Mar 11. | Jul 26 |
| Cabbage | Feb 11 | Mar 11–Mar 25 | 245 | fits: 70 days to maturity, 245 available after Mar 11. | Aug 19 |
| Radish | — | Feb 11–May 6 | 259 | two-plantings: Plant Feb 11 and again by Sep 19; both mature before Oct 28. | Sep 19 |
| Beets | — | Feb 11–May 6 | 259 | two-plantings: Plant Feb 11 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Potatoes | — | Mar 25–Apr 1 | 217 | fits: 90 days to maturity, 217 available after Mar 25. | — |
| Garlic | — | Oct 21 | 301 | overwinter: Plant Oct 21 to Nov 11; harvest the following summer. | Nov 11 |
| Strawberry | — | Mar 4–Apr 29 | 252 | perennial: A perennial: plant Mar 4; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 11 | Apr 15–Apr 22 | 168 | fits: 75 days to maturity, 168 available after Apr 15. | Jul 3 |
| Pumpkin | Mar 25 | Apr 22–Apr 22 | 161 | fits: 100 days to maturity, 161 available after Apr 22. | Jun 8 |
| Cauliflower | Feb 25 | Apr 1–Apr 15 | 210 | fits: 75 days to maturity, 210 available after Apr 1. | Jul 31 |
| Swiss Chard | Feb 11 | Mar 25–Mar 25 | 217 | two-plantings: Plant Mar 25 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Arugula | — | Feb 11–May 6 | 273 | two-plantings: Plant Feb 11 and again by Sep 18; both mature before Nov 11. | Sep 18 |
| Brussel Sprouts | Feb 11 | Mar 11–Mar 25 | 245 | fits: 100 days to maturity, 245 available after Mar 11. | Jul 20 |
| Butternut Squash | Mar 25 | Apr 22–Apr 29 | 161 | fits: 100 days to maturity, 161 available after Apr 22. | Jun 8 |
| Eggplant | Feb 18 | Apr 22–Apr 29 | 154 | fits: 70 days to maturity, 154 available after Apr 22. | Jul 1 |
| Okra | Mar 11 | Apr 15–Apr 22 | 175 | two-plantings: Plant Apr 15 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Basil | Mar 4 | Apr 29–Apr 29 | 161 | two-plantings: Plant Apr 29 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Cilantro | — | Mar 11–Apr 1 | 231 | two-plantings: Plant Mar 11 and again by Aug 25; both mature before Oct 28. | Aug 25 |
| Parsley | Jan 28 | Apr 15–Apr 22 | 196 | fits: 70 days to maturity, 196 available after Apr 15. | Aug 5 |
| Celery | Jan 28 | Apr 15–Apr 29 | 196 | fits: 120 days to maturity, 196 available after Apr 15. | Jun 16 |
| Scallions | Jan 28 | Mar 11–Mar 25 | 245 | two-plantings: Plant Mar 11 and again by Aug 29; both mature before Nov 11. | Aug 29 |
| Turnip | — | Mar 11–Mar 25 | 245 | two-plantings: Plant Mar 11 and again by Sep 8; both mature before Nov 11. | Sep 8 |
| Kohlrabi | — | Feb 25–Mar 11 | 259 | two-plantings: Plant Feb 25 and again by Sep 3; both mature before Nov 11. | Sep 3 |
| Bok Choy | Mar 11 | Apr 1–Apr 8 | 210 | two-plantings: Plant Apr 1 and again by Aug 30; both mature before Oct 28. | Aug 30 |
| Collards | Jan 28 | Mar 11–Mar 25 | 245 | two-plantings: Plant Mar 11 and again by Aug 29; both mature before Nov 11. | Aug 29 |
| Cantaloupe | Mar 25 | Apr 22–Apr 29 | 154 | fits: 85 days to maturity, 154 available after Apr 22. | Jun 16 |
| Chives | Jan 14 | Apr 15–Apr 22 | 210 | fits: 90 days to maturity, 210 available after Apr 15. | — |
| Dill | — | Feb 11–May 6 | 259 | two-plantings: Plant Feb 11 and again by Aug 20; both mature before Oct 28. | Aug 20 |
| Oregano | Jan 28 | Apr 15–Apr 22 | 210 | fits: 80 days to maturity, 210 available after Apr 15. | — |
| Rosemary | Jan 14 | Apr 15–Apr 22 | 196 | fits: 80 days to maturity, 196 available after Apr 15. | — |
| Sage | Feb 11 | Apr 15–Apr 22 | 210 | fits: 75 days to maturity, 210 available after Apr 15. | — |
| Thyme | Jan 28 | Apr 15–Apr 22 | 210 | fits: 90 days to maturity, 210 available after Apr 15. | — |
| Calendula | Feb 25 | Mar 25–Apr 8 | 217 | two-plantings: Plant Mar 25 and again by Aug 25; both mature before Oct 28. | Aug 25 |
| Cosmos | Mar 11 | Apr 8–Apr 22 | 182 | two-plantings: Plant Apr 8 and again by Jul 25; both mature before Oct 7. | Jul 25 |
| Lavender | Jan 14 | Apr 8–Apr 22 | 217 | fits: 90 days to maturity, 217 available after Apr 8. | — |
| Marigolds | Feb 25 | Apr 8–Apr 15 | 182 | two-plantings: Plant Apr 8 and again by Aug 4; both mature before Oct 7. | Aug 4 |
| Melons | Mar 25 | Apr 22–Apr 29 | 154 | fits: 85 days to maturity, 154 available after Apr 22. | Jun 16 |
| Mint | — | Apr 8–Apr 22 | 217 | fits: 90 days to maturity, 217 available after Apr 8. | — |
| Nasturtiums | Mar 11 | Apr 8–Apr 15 | 182 | two-plantings: Plant Apr 8 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Pole Beans | — | Apr 15–Apr 29 | 175 | fits: 65 days to maturity, 175 available after Apr 15. | Jul 20 |
| Spaghetti Squash | Mar 25 | Apr 22–Apr 29 | 161 | fits: 90 days to maturity, 161 available after Apr 22. | Jun 18 |
| Sunflowers | — | Apr 8–Apr 22 | 182 | fits: 70 days to maturity, 182 available after Apr 8. | Jul 15 |
| Tomatillos | Feb 11 | Apr 15–Apr 22 | 161 | fits: 75 days to maturity, 161 available after Apr 15. | Jun 26 |
| Watermelon | Mar 25 | Apr 15–Apr 22 | 161 | fits: 80 days to maturity, 161 available after Apr 15. | Jun 21 |
| Yellow Squash | Mar 25 | Apr 22–Apr 29 | 168 | two-plantings: Plant Apr 22 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Zinnias | Mar 11 | Apr 8–Apr 22 | 182 | two-plantings: Plant Apr 8 and again by Jul 25; both mature before Oct 7. | Jul 25 |
Month by month in Hermiston
| Month | What to do |
|---|---|
| January | Start indoors: Chives (Jan 14), Lavender (Jan 14), Onion (Jan 14), Rosemary (Jan 14), Celery (Jan 28), Collards (Jan 28), +5 more. |
| February | Start indoors: Broccoli (Feb 11), Brussel Sprouts (Feb 11), Cabbage (Feb 11), Lettuce (Feb 11), Sage (Feb 11), Swiss Chard (Feb 11), +6 more. Direct sow from: Arugula (Feb 11), Beets (Feb 11), Dill (Feb 11), Peas (Feb 11), Radish (Feb 11), Spinach (Feb 11), +1 more. |
| March | Start indoors: Basil (Mar 4), Tomato (Mar 4), Bok Choy (Mar 11), Corn (Mar 11), Cosmos (Mar 11), Nasturtiums (Mar 11), +11 more. Direct sow from: Cilantro (Mar 11), Turnip (Mar 11), Carrots (Mar 18), Potatoes (Mar 25). Transplant from: Broccoli (Mar 11), Brussel Sprouts (Mar 11), Cabbage (Mar 11), Collards (Mar 11), Kale (Mar 11), Lettuce (Mar 11), +4 more. Plant: Strawberry (Mar 4). |
| April | Direct sow from: Sunflowers (Apr 8), Beans (Apr 15), Pole Beans (Apr 15). Transplant from: Bok Choy (Apr 1), Cauliflower (Apr 1), Cosmos (Apr 8), Lavender (Apr 8), Marigolds (Apr 8), Mint (Apr 8), +25 more. Last frost around April 8. |
| May | Frost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini. |
| June | Last sowing dates: Butternut Squash (Jun 8), Pumpkin (Jun 8), Cantaloupe (Jun 16), Celery (Jun 16), Melons (Jun 16), Spaghetti Squash (Jun 18), +4 more. |
| July | Last sowing dates: Eggplant (Jul 1), Corn (Jul 3), Sunflowers (Jul 15), Brussel Sprouts (Jul 20), Pole Beans (Jul 20), Basil (Jul 25), +9 more. |
| August | Last sowing dates: Beans (Aug 1), Marigolds (Aug 4), Parsley (Aug 5), Peas (Aug 10), Cabbage (Aug 19), Carrots (Aug 19), +9 more. |
| September | Last sowing dates: Kale (Sep 3), Kohlrabi (Sep 3), Turnip (Sep 8), Arugula (Sep 18), Spinach (Sep 18), Radish (Sep 19). |
| October | Direct sow from: Garlic (Oct 21). First frost around October 21. |
| November | Last sowing dates: Garlic (Nov 11). |
| 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 Hermiston, OR (ZIP 97838)?
The median last spring frost date for Hermiston, OR (ZIP code 97838) is around April 8. 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 March 18; one in ten it runs past April 29.
What is the first fall frost date in Hermiston, OR?
The median first fall frost date for Hermiston, OR is around October 21. 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 October 5 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Hermiston, OR?
The frost-free growing season in Hermiston is about 196 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 Hermiston (196 frost-free days, a long season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Hermiston, OR?
Hermiston, OR is in USDA hardiness zone 7b (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 Hermiston, OR?
Start tomatoes indoors Mar 4 and plant out Apr 22 in Hermiston. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Hermiston?
Two: plant Mar 11 and again by Aug 30; both mature before Oct 28.
When do I plant garlic in Hermiston?
Oct 21 to Nov 11; it overwinters and is ready the following summer.
Can I get two tomato crops in Hermiston?
Yes: plant out Apr 22 for a summer crop, and set out a second round of transplants by Jun 21 for a fall crop.
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