Mapleton, OR planting calendar
- USDA zone
- 9a20 to 25 °F
- Last frost
- Feb 15avg, 32°F
- First frost
- Dec 9avg, 32°F
- Growing season
- 306days
Mapleton, Oregon is in USDA plant hardiness zone 9a. Its average last spring frost is around February 15 and the first fall frost around December 9, giving a growing season of about 306 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.
Mapleton planting calendar
Each crop's windows are counted from Mapleton'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 1 – Jan 4 | Feb 22 – Mar 1 | Apr 23 – May 13 | — |
| Pepper | Very tender | Jan 1 | Mar 1 – Mar 8 | Apr 30 – May 30 | — |
| Cucumber | Tender | Jan 18 – Jan 25 | Feb 22 – Mar 1 | Apr 13 – May 3 | — |
| Summer squash / zucchini | Tender | — | Feb 22 – Mar 1 | Apr 8 – Apr 23 | — |
| Bush bean | Tender | — | Feb 22 – Mar 1 | Apr 13 – Apr 23 | Oct 10 – Oct 20 |
| Sweet corn | Tender | — | Feb 15 – Mar 1 | Apr 16 – May 16 | — |
| Basil | Very tender | Jan 4 – Jan 18 | Feb 22 – Mar 1 | Mar 24 – Apr 8 | — |
| Lettuce | Half-hardy | Jan 4 – Jan 18 | Jan 18 – Feb 1 | Mar 4 – Mar 19 | Sep 26 – Oct 11 |
| Pea | Hardy | — | Jan 4 – Jan 18 | Feb 28 – Mar 15 | Sep 16 – Oct 1 |
| Spinach | Hardy | — | Jan 4 – Jan 18 | Feb 13 – Feb 23 | Oct 6 – Oct 16 |
| Carrot | Half-hardy | — | Jan 25 – Feb 1 | Mar 26 – Apr 15 | Sep 6 – Sep 26 |
| Broccoli | Half-hardy | Jan 1 – Jan 4 | Jan 18 – Feb 1 | Mar 14 – Apr 3 | Sep 11 – Oct 1 |
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 USC00355204. 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 | Mar 30 | Apr 29 | Nov 16 | Dec 11 | 231 |
| 32°F (freeze) | Feb 15 | Mar 19 | Dec 9 | Jan 24 | 306 |
| 28°F | Jan 6 | Feb 19 | Dec 25 | Feb 11 | 365 |
| 24°F | Dec 24 | Jan 15 | Dec 22 | Jan 13 | 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) | 2,599 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 5,748 | cool-season crops (brassicas, greens) |
Hardiness zone 9a
Mapleton 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 Mapleton?
- Mapleton, 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 Mapleton?
- The average (median) last spring frost at 32°F is around February 15, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as March 19, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Mapleton?
- The average first fall frost at 32°F is around December 9. That leaves a growing season of about 306 days between the average last spring and first fall frosts.
- When should I start tomatoes in Mapleton?
- Start tomato seeds indoors about Jan 1 – Jan 4 and transplant them outside about Feb 22 – Mar 1, once the danger of frost has passed. Estimated first harvest is around Apr 23 – May 13.
- How long is the growing season in Mapleton?
- About 306 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~February 15) and the average first fall frost (~December 9). 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 USC00355204 (Mapleton, 10.5 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.