Jarrell, TX planting calendar
- USDA zone
- 8b15 to 20 °F
- Last frost
- Mar 6avg, 32°F
- First frost
- Nov 24avg, 32°F
- Growing season
- 259days
Jarrell, Texas is in USDA plant hardiness zone 8b. Its average last spring frost is around March 6 and the first fall frost around November 24, giving a growing season of about 259 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.
Jarrell planting calendar
Each crop's windows are counted from Jarrell'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 9 – Jan 23 | Mar 13 – Mar 20 | May 12 – Jun 1 | — |
| Pepper | Very tender | Jan 1 – Jan 9 | Mar 20 – Mar 27 | May 19 – Jun 18 | — |
| Cucumber | Tender | Feb 6 – Feb 13 | Mar 13 – Mar 20 | May 2 – May 22 | — |
| Summer squash / zucchini | Tender | — | Mar 13 – Mar 20 | Apr 27 – May 12 | — |
| Bush bean | Tender | — | Mar 13 – Mar 20 | May 2 – May 12 | Sep 25 – Oct 5 |
| Sweet corn | Tender | — | Mar 6 – Mar 20 | May 5 – Jun 4 | — |
| Basil | Very tender | Jan 23 – Feb 6 | Mar 13 – Mar 20 | Apr 12 – Apr 27 | — |
| Lettuce | Half-hardy | Jan 23 – Feb 6 | Feb 6 – Feb 20 | Mar 23 – Apr 7 | Sep 11 – Sep 26 |
| Pea | Hardy | — | Jan 23 – Feb 6 | Mar 19 – Apr 3 | Sep 1 – Sep 16 |
| Spinach | Hardy | — | Jan 23 – Feb 6 | Mar 4 – Mar 14 | Sep 21 – Oct 1 |
| Carrot | Half-hardy | — | Feb 13 – Feb 20 | Apr 14 – May 4 | Aug 22 – Sep 11 |
| Broccoli | Half-hardy | Jan 9 – Jan 23 | Feb 6 – Feb 20 | Apr 2 – Apr 22 | Aug 27 – Sep 16 |
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 USC00413507. 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 22 | Apr 10 | Nov 13 | Dec 1 | 232 |
| 32°F (freeze) | Mar 6 | Mar 30 | Nov 24 | Dec 10 | 259 |
| 28°F | Feb 23 | Mar 16 | Dec 5 | Jan 1 | 288 |
| 24°F | Feb 3 | Mar 6 | Dec 22 | Jan 27 | 323 |
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) | 6,670 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 9,995 | cool-season crops (brassicas, greens) |
Hardiness zone 8b
Jarrell sits in USDA plant hardiness zone 8b on the 2023 map — meaning its average annual extreme minimum winter temperature is about 15 to 20 °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 8b, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Jarrell?
- Jarrell, Texas is in USDA plant hardiness zone 8b on the 2023 map (average annual extreme minimum temperature 15 to 20 °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 Jarrell?
- The average (median) last spring frost at 32°F is around March 6, 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 30, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Jarrell?
- The average first fall frost at 32°F is around November 24. That leaves a growing season of about 259 days between the average last spring and first fall frosts.
- When should I start tomatoes in Jarrell?
- Start tomato seeds indoors about Jan 9 – Jan 23 and transplant them outside about Mar 13 – Mar 20, once the danger of frost has passed. Estimated first harvest is around May 12 – Jun 1.
- How long is the growing season in Jarrell?
- About 259 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~March 6) and the average first fall frost (~November 24). 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 USC00413507 (Georgetown Lake, 7.3 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.