Portland, TX planting calendar
- USDA zone
- 10a30 to 35 °F
- Last frost
- Jan 28avg, 32°F
- First frost
- Dec 21avg, 32°F
- Growing season
- 331days
Portland, Texas is in USDA plant hardiness zone 10a. Its average last spring frost is around January 28 and the first fall frost around December 21, giving a growing season of about 331 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.
Portland planting calendar
Each crop's windows are counted from Portland'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 | Feb 4 – Feb 11 | Apr 5 – Apr 25 | — |
| Pepper | Very tender | Jan 1 | Feb 11 – Feb 18 | Apr 12 – May 12 | — |
| Cucumber | Tender | Jan 1 – Jan 7 | Feb 4 – Feb 11 | Mar 26 – Apr 15 | — |
| Summer squash / zucchini | Tender | — | Feb 4 – Feb 11 | Mar 21 – Apr 5 | — |
| Bush bean | Tender | — | Feb 4 – Feb 11 | Mar 26 – Apr 5 | Oct 22 – Nov 1 |
| Sweet corn | Tender | — | Jan 28 – Feb 11 | Mar 29 – Apr 28 | — |
| Basil | Very tender | Jan 1 | Feb 4 – Feb 11 | Mar 6 – Mar 21 | — |
| Lettuce | Half-hardy | Jan 1 | Jan 1 – Jan 14 | Feb 15 – Mar 2 | Oct 8 – Oct 23 |
| Pea | Hardy | — | Jan 1 | Feb 25 – Mar 12 | Sep 28 – Oct 13 |
| Spinach | Hardy | — | Jan 1 | Feb 10 – Feb 20 | Oct 18 – Oct 28 |
| Carrot | Half-hardy | — | Jan 7 – Jan 14 | Mar 8 – Mar 28 | Sep 18 – Oct 8 |
| Broccoli | Half-hardy | Jan 1 | Jan 1 – Jan 14 | Feb 25 – Mar 17 | Sep 23 – Oct 13 |
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 USW00012924. 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 | Feb 16 | Mar 11 | Dec 5 | Jan 3 | 294 |
| 32°F (freeze) | Jan 28 | Feb 28 | Dec 21 | Jan 26 | 331 |
| 28°F | Jan 8 | Feb 16 | Dec 30 | Feb 4 | 363 |
| 24°F | Jan 2 | Feb 5 | Jan 1 | Feb 5 | 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) | 8,481 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 12,066 | cool-season crops (brassicas, greens) |
Hardiness zone 10a
Portland sits in USDA plant hardiness zone 10a on the 2023 map — meaning its average annual extreme minimum winter temperature is about 30 to 35 °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 10a, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Portland?
- Portland, Texas is in USDA plant hardiness zone 10a on the 2023 map (average annual extreme minimum temperature 30 to 35 °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 Portland?
- The average (median) last spring frost at 32°F is around January 28, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as February 28, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Portland?
- The average first fall frost at 32°F is around December 21. That leaves a growing season of about 331 days between the average last spring and first fall frosts.
- When should I start tomatoes in Portland?
- Start tomato seeds indoors about Jan 1 and transplant them outside about Feb 4 – Feb 11, once the danger of frost has passed. Estimated first harvest is around Apr 5 – Apr 25.
- How long is the growing season in Portland?
- About 331 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~January 28) and the average first fall frost (~December 21). 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 USW00012924 (Corpus Christi, 6.7 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.