Clemson, SC 29634 planting calendar
- USDA zone
- 8b15 to 20 °F
- Last frost
- Apr 1avg, 32°F
- First frost
- Nov 3avg, 32°F
- Growing season
- 217days
Clemson, South Carolina is in USDA plant hardiness zone 8b. Its average last spring frost is around April 1 and the first fall frost around November 3, giving a growing season of about 217 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.
Clemson planting calendar
Each crop's windows are counted from Clemson'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 | Feb 4 – Feb 18 | Apr 8 – Apr 15 | Jun 7 – Jun 27 | — |
| Pepper | Very tender | Jan 21 – Feb 4 | Apr 15 – Apr 22 | Jun 14 – Jul 14 | — |
| Cucumber | Tender | Mar 4 – Mar 11 | Apr 8 – Apr 15 | May 28 – Jun 17 | — |
| Summer squash / zucchini | Tender | — | Apr 8 – Apr 15 | May 23 – Jun 7 | — |
| Bush bean | Tender | — | Apr 8 – Apr 15 | May 28 – Jun 7 | Sep 4 – Sep 14 |
| Sweet corn | Tender | — | Apr 1 – Apr 15 | May 31 – Jun 30 | — |
| Basil | Very tender | Feb 18 – Mar 4 | Apr 8 – Apr 15 | May 8 – May 23 | — |
| Lettuce | Half-hardy | Feb 18 – Mar 4 | Mar 4 – Mar 18 | Apr 18 – May 3 | Aug 21 – Sep 5 |
| Pea | Hardy | — | Feb 18 – Mar 4 | Apr 14 – Apr 29 | Aug 11 – Aug 26 |
| Spinach | Hardy | — | Feb 18 – Mar 4 | Mar 30 – Apr 9 | Aug 31 – Sep 10 |
| Carrot | Half-hardy | — | Mar 11 – Mar 18 | May 10 – May 30 | Aug 1 – Aug 21 |
| Broccoli | Half-hardy | Feb 4 – Feb 18 | Mar 4 – Mar 18 | Apr 28 – May 18 | Aug 6 – Aug 26 |
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 USC00381770. 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 14 | Apr 30 | Oct 25 | Nov 6 | 195 |
| 32°F (freeze) | Apr 1 | Apr 18 | Nov 3 | Nov 17 | 217 |
| 28°F | Mar 19 | Apr 6 | Nov 13 | Dec 3 | 241 |
| 24°F | Mar 4 | Mar 24 | Nov 29 | Dec 27 | 269 |
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) | 5,008 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 8,032 | cool-season crops (brassicas, greens) |
Hardiness zone 8b
Clemson 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 Clemson?
- Clemson, South Carolina 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 Clemson?
- The average (median) last spring frost at 32°F is around April 1, 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 18, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Clemson?
- The average first fall frost at 32°F is around November 3. That leaves a growing season of about 217 days between the average last spring and first fall frosts.
- When should I start tomatoes in Clemson?
- Start tomato seeds indoors about Feb 4 – Feb 18 and transplant them outside about Apr 8 – Apr 15, once the danger of frost has passed. Estimated first harvest is around Jun 7 – Jun 27.
- How long is the growing season in Clemson?
- About 217 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~April 1) and the average first fall frost (~November 3). 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 USC00381770 (Clemson Univ, 2 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.