Fort Smith, AR planting calendar
- USDA zone
- 8a10 to 15 °F
- Last frost
- Mar 25avg, 32°F
- First frost
- Nov 6avg, 32°F
- Growing season
- 224days
Fort Smith, Arkansas is in USDA plant hardiness zone 8a. Its average last spring frost is around March 25 and the first fall frost around November 6, giving a growing season of about 224 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.
Fort Smith planting calendar
Each crop's windows are counted from Fort Smith'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 28 – Feb 11 | Apr 1 – Apr 8 | May 31 – Jun 20 | — |
| Pepper | Very tender | Jan 14 – Jan 28 | Apr 8 – Apr 15 | Jun 7 – Jul 7 | — |
| Cucumber | Tender | Feb 25 – Mar 4 | Apr 1 – Apr 8 | May 21 – Jun 10 | — |
| Summer squash / zucchini | Tender | — | Apr 1 – Apr 8 | May 16 – May 31 | — |
| Bush bean | Tender | — | Apr 1 – Apr 8 | May 21 – May 31 | Sep 7 – Sep 17 |
| Sweet corn | Tender | — | Mar 25 – Apr 8 | May 24 – Jun 23 | — |
| Basil | Very tender | Feb 11 – Feb 25 | Apr 1 – Apr 8 | May 1 – May 16 | — |
| Lettuce | Half-hardy | Feb 11 – Feb 25 | Feb 25 – Mar 11 | Apr 11 – Apr 26 | Aug 24 – Sep 8 |
| Pea | Hardy | — | Feb 11 – Feb 25 | Apr 7 – Apr 22 | Aug 14 – Aug 29 |
| Spinach | Hardy | — | Feb 11 – Feb 25 | Mar 23 – Apr 2 | Sep 3 – Sep 13 |
| Carrot | Half-hardy | — | Mar 4 – Mar 11 | May 3 – May 23 | Aug 4 – Aug 24 |
| Broccoli | Half-hardy | Jan 28 – Feb 11 | Feb 25 – Mar 11 | Apr 21 – May 11 | Aug 9 – Aug 29 |
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 USW00013964. 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 8 | Apr 25 | Oct 28 | Nov 11 | 203 |
| 32°F (freeze) | Mar 25 | Apr 11 | Nov 6 | Nov 21 | 224 |
| 28°F | Mar 11 | Apr 2 | Nov 17 | Dec 4 | 250 |
| 24°F | Feb 27 | Mar 18 | Nov 30 | Dec 21 | 275 |
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) | 5,500 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 8,457 | cool-season crops (brassicas, greens) |
Hardiness zone 8a
Fort Smith sits in USDA plant hardiness zone 8a on the 2023 map — meaning its average annual extreme minimum winter temperature is about 10 to 15 °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 8a, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Fort Smith?
- Fort Smith, Arkansas is in USDA plant hardiness zone 8a on the 2023 map (average annual extreme minimum temperature 10 to 15 °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 Fort Smith?
- The average (median) last spring frost at 32°F is around March 25, 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 11, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Fort Smith?
- The average first fall frost at 32°F is around November 6. That leaves a growing season of about 224 days between the average last spring and first fall frosts.
- When should I start tomatoes in Fort Smith?
- Start tomato seeds indoors about Jan 28 – Feb 11 and transplant them outside about Apr 1 – Apr 8, once the danger of frost has passed. Estimated first harvest is around May 31 – Jun 20.
- How long is the growing season in Fort Smith?
- About 224 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~March 25) and the average first fall frost (~November 6). 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 USW00013964 (Ft Smith Rgnl Ap, 2.4 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.