Jasper, TX planting calendar
- USDA zone
- 9a20 to 25 °F
- Last frost
- Feb 24avg, 32°F
- First frost
- Dec 1avg, 32°F
- Growing season
- 280days
Jasper, Texas is in USDA plant hardiness zone 9a. Its average last spring frost is around February 24 and the first fall frost around December 1, giving a growing season of about 280 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.
Jasper planting calendar
Each crop's windows are counted from Jasper'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 13 | Mar 3 – Mar 10 | May 2 – May 22 | — |
| Pepper | Very tender | Jan 1 | Mar 10 – Mar 17 | May 9 – Jun 8 | — |
| Cucumber | Tender | Jan 27 – Feb 3 | Mar 3 – Mar 10 | Apr 22 – May 12 | — |
| Summer squash / zucchini | Tender | — | Mar 3 – Mar 10 | Apr 17 – May 2 | — |
| Bush bean | Tender | — | Mar 3 – Mar 10 | Apr 22 – May 2 | Oct 2 – Oct 12 |
| Sweet corn | Tender | — | Feb 24 – Mar 10 | Apr 25 – May 25 | — |
| Basil | Very tender | Jan 13 – Jan 27 | Mar 3 – Mar 10 | Apr 2 – Apr 17 | — |
| Lettuce | Half-hardy | Jan 13 – Jan 27 | Jan 27 – Feb 10 | Mar 13 – Mar 28 | Sep 18 – Oct 3 |
| Pea | Hardy | — | Jan 13 – Jan 27 | Mar 9 – Mar 24 | Sep 8 – Sep 23 |
| Spinach | Hardy | — | Jan 13 – Jan 27 | Feb 22 – Mar 4 | Sep 28 – Oct 8 |
| Carrot | Half-hardy | — | Feb 3 – Feb 10 | Apr 4 – Apr 24 | Aug 29 – Sep 18 |
| Broccoli | Half-hardy | Jan 1 – Jan 13 | Jan 27 – Feb 10 | Mar 23 – Apr 12 | Sep 3 – Sep 23 |
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 USC00417936. 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 13 | Apr 4 | Nov 19 | Dec 6 | 249 |
| 32°F (freeze) | Feb 24 | Mar 23 | Dec 1 | Dec 27 | 280 |
| 28°F | Feb 3 | Mar 5 | Dec 22 | Jan 21 | 317 |
| 24°F | Jan 23 | Feb 24 | Jan 5 | Feb 4 | 353 |
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) | 7,086 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 10,475 | cool-season crops (brassicas, greens) |
Hardiness zone 9a
Jasper 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 Jasper?
- Jasper, Texas 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 Jasper?
- The average (median) last spring frost at 32°F is around February 24, 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 23, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Jasper?
- The average first fall frost at 32°F is around December 1. That leaves a growing season of about 280 days between the average last spring and first fall frosts.
- When should I start tomatoes in Jasper?
- Start tomato seeds indoors about Jan 1 – Jan 13 and transplant them outside about Mar 3 – Mar 10, once the danger of frost has passed. Estimated first harvest is around May 2 – May 22.
- How long is the growing season in Jasper?
- About 280 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~February 24) and the average first fall frost (~December 1). 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 USC00417936 (Sam Rayburn Dam, 10.8 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.