Powers, OR 97466 planting calendar
- USDA zone
- 9a20 to 25 °F
- Last frost
- Mar 21avg, 32°F
- First frost
- Nov 14avg, 32°F
- Growing season
- 241days
Powers, Oregon is in USDA plant hardiness zone 9a. Its average last spring frost is around March 21 and the first fall frost around November 14, giving a growing season of about 241 days (NOAA 1991–2020 normals, 32°F, median). Start tender crops like tomatoes and peppers indoors weeks before the last frost and set them out afterward; sow hardy crops such as peas, spinach, and lettuce before it. The planner below turns those frost dates into a printable per-crop planting calendar.
Powers planting calendar
Each crop's windows are counted from Powers's average frost dates. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees.
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting |
|---|---|---|---|---|---|
| Tomato | Tender | Jan 24 – Feb 7 | Mar 28 – Apr 4 | May 27 – Jun 16 | — |
| Pepper | Very tender | Jan 10 – Jan 24 | Apr 4 – Apr 11 | Jun 3 – Jul 3 | — |
| Cucumber | Tender | Feb 21 – Feb 28 | Mar 28 – Apr 4 | May 17 – Jun 6 | — |
| Summer squash / zucchini | Tender | — | Mar 28 – Apr 4 | May 12 – May 27 | — |
| Bush bean | Tender | — | Mar 28 – Apr 4 | May 17 – May 27 | Sep 15 – Sep 25 |
| Sweet corn | Tender | — | Mar 21 – Apr 4 | May 20 – Jun 19 | — |
| Basil | Very tender | Feb 7 – Feb 21 | Mar 28 – Apr 4 | Apr 27 – May 12 | — |
| Lettuce | Half-hardy | Feb 7 – Feb 21 | Feb 21 – Mar 7 | Apr 7 – Apr 22 | Sep 1 – Sep 16 |
| Pea | Hardy | — | Feb 7 – Feb 21 | Apr 3 – Apr 18 | Aug 22 – Sep 6 |
| Spinach | Hardy | — | Feb 7 – Feb 21 | Mar 19 – Mar 29 | Sep 11 – Sep 21 |
| Carrot | Half-hardy | — | Feb 28 – Mar 7 | Apr 29 – May 19 | Aug 12 – Sep 1 |
| Broccoli | Half-hardy | Jan 24 – Feb 7 | Feb 21 – Mar 7 | Apr 17 – May 7 | Aug 17 – Sep 6 |
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Frost & freeze dates
From NOAA's 1991–2020 Climate Normals at station USC00356820. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 (p10 for spring, p90 for fall) — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | Apr 20 | May 9 | Oct 22 | Nov 14 | 183 |
| 32°F (freeze) | Mar 21 | Apr 12 | Nov 14 | Dec 14 | 241 |
| 28°F | Feb 6 | Mar 18 | Dec 9 | Jan 30 | 310 |
| 24°F | Jan 1 | Feb 12 | Dec 20 | Feb 1 | 365 |
32°F is the standard "freeze" line that damages tender crops; lighter 36°F frost can nip the most cold-sensitive plants, while hardy crops shrug off light frost down toward 28°F. Use the threshold that matches what you are protecting.
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. Warm-season crops need a long, warm GDD total; a short, cool GDD total favors greens and brassicas.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 2,467 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 5,477 | cool-season crops (brassicas, greens) |
Hardiness zone 9a
Powers sits in USDA plant hardiness zone 9a on the 2023 map — meaning its average annual extreme minimum winter temperature is about 20 to 25 °F. That number tells you which perennials, shrubs, and trees reliably survive an average winter here; it does not set your planting dates, which come from the frost calendar above.
Explore more places in zone 9a, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Powers?
- Powers, Oregon is in USDA plant hardiness zone 9a on the 2023 map (average annual extreme minimum temperature 20 to 25 °F) — from the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. See the methodology page for sources.
- When is the last frost in Powers?
- The average (median) last spring frost at 32°F is around March 21, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as April 12, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Powers?
- The average first fall frost at 32°F is around November 14. That leaves a growing season of about 241 days between the average last spring and first fall frosts.
- When should I start tomatoes in Powers?
- Start tomato seeds indoors about Jan 24 – Feb 7 and transplant them outside about Mar 28 – Apr 4, once the danger of frost has passed. Estimated first harvest is around May 27 – Jun 16.
- How long is the growing season in Powers?
- About 241 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~March 21) and the average first fall frost (~November 14). Cold-hardy crops extend usable time at both ends; frost-tender crops fit inside it.
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020 for station USC00356820 (Powers, 4.6 km away). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.