Frost Dates for Ontario, OR 97914
Last spring frost May 6 · First fall frost October 2 · 149 frost-free days · USDA Zone 7a
ZIP 97914 has about 19,700 people.
Moderate season: 149 frost-free days. Spring frost risk spans April 16–May 31 (45 days). Fall frost risk spans September 15–October 18 (33 days).
Frost probability for 97914
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 31 | May 6 | April 16 |
| Fall (first frost) | September 15 | October 2 | October 18 |
Dates come from NOAA 1971–2000 freeze probabilities at PAYETTE (12.0 km away); the 50% date is the median year.
Which crops fit a 149-day season in Ontario
In Ontario (149 frost-free days, a moderate season), 34 of 56 planner crops fit outright, 21 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Apr 1 | May 20–May 27 | 107 | fits: 80 days to maturity, 107 available after May 20. | Jun 2 |
| Pepper | Mar 25 | May 20–May 27 | 107 | fits: 75 days to maturity, 107 available after May 20. | Jun 7 |
| Lettuce | Mar 11 | Apr 8–Apr 15 | 184 | two-plantings: Plant Apr 8 and again by Aug 11; both mature before Oct 9. | Aug 11 |
| Carrots | — | Apr 15–Apr 22 | 191 | fits: 70 days to maturity, 191 available after Apr 15. | Jul 31 |
| Cucumber | Apr 15 | May 20–May 27 | 121 | fits: 60 days to maturity, 121 available after May 20. | Jul 6 |
| Beans | — | May 13–May 27 | 135 | two-plantings: Plant May 13 and again by Jul 13; both mature before Sep 25. | Jul 13 |
| Peas | — | Mar 11–May 20 | 212 | fits: 65 days to maturity, 212 available after Mar 11. | Jul 22 |
| Zucchini | Apr 22 | May 20–May 27 | 121 | fits: 55 days to maturity, 121 available after May 20. | Jul 11 |
| Onion | Feb 11 | Apr 8–Apr 22 | 184 | fits: 100 days to maturity, 184 available after Apr 8. | — |
| Spinach | — | Mar 11–Apr 29 | 226 | two-plantings: Plant Mar 11 and again by Aug 30; both mature before Oct 23. | Aug 30 |
| Kale | Feb 25 | Apr 8–Apr 22 | 198 | two-plantings: Plant Apr 8 and again by Aug 15; both mature before Oct 23. | Aug 15 |
| Broccoli | Mar 11 | Apr 8–Apr 22 | 184 | fits: 80 days to maturity, 184 available after Apr 8. | Jul 7 |
| Cabbage | Mar 11 | Apr 8–Apr 22 | 198 | fits: 70 days to maturity, 198 available after Apr 8. | Jul 31 |
| Radish | — | Mar 11–Jun 3 | 212 | two-plantings: Plant Mar 11 and again by Aug 31; both mature before Oct 9. | Aug 31 |
| Beets | — | Mar 11–Jun 3 | 212 | two-plantings: Plant Mar 11 and again by Aug 1; both mature before Oct 9. | Aug 1 |
| Potatoes | — | Apr 22–Apr 29 | 170 | fits: 90 days to maturity, 170 available after Apr 22. | — |
| Garlic | — | Oct 2 | 254 | overwinter: Plant Oct 2 to Oct 23; harvest the following summer. | Oct 23 |
| Strawberry | — | Apr 1–May 27 | 205 | perennial: A perennial: plant Apr 1; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 8 | May 13–May 20 | 121 | fits: 75 days to maturity, 121 available after May 13. | Jun 14 |
| Pumpkin | Apr 22 | May 20–May 20 | 114 | fits: 100 days to maturity, 114 available after May 20. | — |
| Cauliflower | Mar 25 | Apr 29–May 13 | 163 | fits: 75 days to maturity, 163 available after Apr 29. | Jul 12 |
| Swiss Chard | Mar 11 | Apr 22–Apr 22 | 170 | two-plantings: Plant Apr 22 and again by Aug 1; both mature before Oct 9. | Aug 1 |
| Arugula | — | Mar 11–Jun 3 | 226 | two-plantings: Plant Mar 11 and again by Aug 30; both mature before Oct 23. | Aug 30 |
| Brussel Sprouts | Mar 11 | Apr 8–Apr 22 | 198 | fits: 100 days to maturity, 198 available after Apr 8. | Jul 1 |
| Butternut Squash | Apr 22 | May 20–May 27 | 114 | fits: 100 days to maturity, 114 available after May 20. | — |
| Eggplant | Mar 18 | May 20–May 27 | 107 | fits: 70 days to maturity, 107 available after May 20. | Jun 12 |
| Okra | Apr 8 | May 13–May 20 | 128 | two-plantings: Plant May 13 and again by Jul 11; both mature before Sep 18. | Jul 11 |
| Basil | Apr 1 | May 27–May 27 | 114 | fits: 60 days to maturity, 114 available after May 27. | Jul 6 |
| Cilantro | — | Apr 8–Apr 29 | 184 | two-plantings: Plant Apr 8 and again by Aug 6; both mature before Oct 9. | Aug 6 |
| Parsley | Feb 25 | May 13–May 20 | 149 | fits: 70 days to maturity, 149 available after May 13. | Jul 17 |
| Celery | Feb 25 | May 13–May 27 | 149 | fits: 120 days to maturity, 149 available after May 13. | May 28 |
| Scallions | Feb 25 | Apr 8–Apr 22 | 198 | two-plantings: Plant Apr 8 and again by Aug 10; both mature before Oct 23. | Aug 10 |
| Turnip | — | Apr 8–Apr 22 | 198 | two-plantings: Plant Apr 8 and again by Aug 20; both mature before Oct 23. | Aug 20 |
| Kohlrabi | — | Mar 25–Apr 8 | 212 | two-plantings: Plant Mar 25 and again by Aug 15; both mature before Oct 23. | Aug 15 |
| Bok Choy | Apr 8 | Apr 29–May 6 | 163 | two-plantings: Plant Apr 29 and again by Aug 11; both mature before Oct 9. | Aug 11 |
| Collards | Feb 25 | Apr 8–Apr 22 | 198 | two-plantings: Plant Apr 8 and again by Aug 10; both mature before Oct 23. | Aug 10 |
| Cantaloupe | Apr 22 | May 20–May 27 | 107 | fits: 85 days to maturity, 107 available after May 20. | May 28 |
| Chives | Feb 11 | May 13–May 20 | 163 | fits: 90 days to maturity, 163 available after May 13. | — |
| Dill | — | Mar 11–Jun 3 | 212 | two-plantings: Plant Mar 11 and again by Aug 1; both mature before Oct 9. | Aug 1 |
| Oregano | Feb 25 | May 13–May 20 | 163 | fits: 80 days to maturity, 163 available after May 13. | — |
| Rosemary | Feb 11 | May 13–May 20 | 149 | fits: 80 days to maturity, 149 available after May 13. | — |
| Sage | Mar 11 | May 13–May 20 | 163 | fits: 75 days to maturity, 163 available after May 13. | — |
| Thyme | Feb 25 | May 13–May 20 | 163 | fits: 90 days to maturity, 163 available after May 13. | — |
| Calendula | Mar 25 | Apr 22–May 6 | 170 | two-plantings: Plant Apr 22 and again by Aug 6; both mature before Oct 9. | Aug 6 |
| Cosmos | Apr 8 | May 6–May 20 | 135 | two-plantings: Plant May 6 and again by Jul 6; both mature before Sep 18. | Jul 6 |
| Lavender | Feb 11 | May 6–May 20 | 170 | fits: 90 days to maturity, 170 available after May 6. | — |
| Marigolds | Mar 25 | May 6–May 13 | 135 | two-plantings: Plant May 6 and again by Jul 16; both mature before Sep 18. | Jul 16 |
| Melons | Apr 22 | May 20–May 27 | 107 | fits: 85 days to maturity, 107 available after May 20. | May 28 |
| Mint | — | May 6–May 20 | 170 | fits: 90 days to maturity, 170 available after May 6. | — |
| Nasturtiums | Apr 8 | May 6–May 13 | 135 | two-plantings: Plant May 6 and again by Jul 11; both mature before Sep 18. | Jul 11 |
| Pole Beans | — | May 13–May 27 | 128 | fits: 65 days to maturity, 128 available after May 13. | Jul 1 |
| Spaghetti Squash | Apr 22 | May 20–May 27 | 114 | fits: 90 days to maturity, 114 available after May 20. | May 30 |
| Sunflowers | — | May 6–May 20 | 135 | fits: 70 days to maturity, 135 available after May 6. | Jun 26 |
| Tomatillos | Mar 11 | May 13–May 20 | 114 | fits: 75 days to maturity, 114 available after May 13. | Jun 7 |
| Watermelon | Apr 22 | May 13–May 20 | 114 | fits: 80 days to maturity, 114 available after May 13. | Jun 2 |
| Yellow Squash | Apr 22 | May 20–May 27 | 121 | fits: 55 days to maturity, 121 available after May 20. | Jul 11 |
| Zinnias | Apr 8 | May 6–May 20 | 135 | two-plantings: Plant May 6 and again by Jul 6; both mature before Sep 18. | Jul 6 |
Month by month in Ontario
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 11), Lavender (Feb 11), Onion (Feb 11), Rosemary (Feb 11), Celery (Feb 25), Collards (Feb 25), +5 more. |
| March | Start indoors: Broccoli (Mar 11), Brussel Sprouts (Mar 11), Cabbage (Mar 11), Lettuce (Mar 11), Sage (Mar 11), Swiss Chard (Mar 11), +6 more. Direct sow from: Arugula (Mar 11), Beets (Mar 11), Dill (Mar 11), Peas (Mar 11), Radish (Mar 11), Spinach (Mar 11), +1 more. |
| April | Start indoors: Basil (Apr 1), Tomato (Apr 1), Bok Choy (Apr 8), Corn (Apr 8), Cosmos (Apr 8), Nasturtiums (Apr 8), +11 more. Direct sow from: Cilantro (Apr 8), Turnip (Apr 8), Carrots (Apr 15), Potatoes (Apr 22). Transplant from: Broccoli (Apr 8), Brussel Sprouts (Apr 8), Cabbage (Apr 8), Collards (Apr 8), Kale (Apr 8), Lettuce (Apr 8), +6 more. Plant: Strawberry (Apr 1). |
| May | Direct sow from: Sunflowers (May 6), Beans (May 13), Pole Beans (May 13). Transplant from: Cosmos (May 6), Lavender (May 6), Marigolds (May 6), Mint (May 6), Nasturtiums (May 6), Zinnias (May 6), +23 more. Last frost around May 6. Last sowing dates: Cantaloupe (May 28), Celery (May 28), Melons (May 28), Spaghetti Squash (May 30). |
| June | Last sowing dates: Tomato (Jun 2), Watermelon (Jun 2), Pepper (Jun 7), Tomatillos (Jun 7), Eggplant (Jun 12), Corn (Jun 14), +1 more. |
| July | Last sowing dates: Brussel Sprouts (Jul 1), Pole Beans (Jul 1), Basil (Jul 6), Cosmos (Jul 6), Cucumber (Jul 6), Zinnias (Jul 6), +12 more. |
| August | Last sowing dates: Beets (Aug 1), Dill (Aug 1), Swiss Chard (Aug 1), Calendula (Aug 6), Cilantro (Aug 6), Collards (Aug 10), +9 more. |
| September | First fall frost approaching (around October 2). Transplant fall brassicas. Sow spinach, arugula, and radishes. |
| October | Direct sow from: Garlic (Oct 2). First frost around October 2. Last sowing dates: Garlic (Oct 23). |
| 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 Ontario, OR (ZIP 97914)?
The median last spring frost date for Ontario, OR (ZIP code 97914) is around May 6. 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 16; one in ten it runs past May 31.
What is the first fall frost date in Ontario, OR?
The median first fall frost date for Ontario, OR is around October 2. 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 15 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Ontario, OR?
The frost-free growing season in Ontario is about 149 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 Ontario (149 frost-free days, a moderate season), 34 of 56 planner crops fit outright, 21 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Ontario, OR?
Ontario, OR 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 Ontario, OR?
Start tomatoes indoors Apr 1 and plant out May 20 in Ontario. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Ontario?
Two: plant Apr 8 and again by Aug 11; both mature before Oct 9.
When do I plant garlic in Ontario?
Oct 2 to Oct 23; it overwinters and is ready the following summer.
Which nearby ZIP has a longer season?
Caldwell (ZIP 83607) has 165 frost-free days, 16 more than Ontario (ZIP 97914). See Caldwell ZIP 83607 frost dates
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- When to plant in OR
- When to plant Peppers in OR
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- When to plant Butternut Squash in OR
- When to plant Basil in OR
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