When to Plant Onions in South Carolina
In South Carolina, the time to plant onions outside runs from Jan 7 – Jan 21 in Charleston to Mar 23 – Apr 6 in Gaffney. In Charleston, it's Jan 7 – Jan 21. The average last spring frost differs by about 11 weeks across the state (Feb 4 in Charleston, Apr 20 in Gaffney), so use the dates for the town nearest you.
Onions are cold-hardy. Plant sets or transplants early so they grow leaves before long summer days trigger bulbing.
- Start indoors: 10–12 weeks before the last frost.
- Plant outside: 2–4 weeks before the last frost.
Onions planting dates in South Carolina by city
| City | Zone | Start indoors | Plant outside |
|---|---|---|---|
| Aiken | 8b | Dec 25 – Jan 8 | Feb 19 – Mar 5 |
| Anderson | 8a | Dec 29 – Jan 12 | Feb 23 – Mar 9 |
| Beaufort | 9a | Dec 6 – Dec 20 | Jan 31 – Feb 14 |
| Bluffton | 9a | Dec 8 – Dec 22 | Feb 2 – Feb 16 |
| Cayce | 8b | Dec 19 – Jan 2 | Feb 13 – Feb 27 |
| Charleston | 9a | Nov 12 – Nov 26 | Jan 7 – Jan 21 |
| Clemson | 8a | Jan 7 – Jan 21 | Mar 4 – Mar 18 |
| Columbia | 8b | Dec 28 – Jan 11 | Feb 22 – Mar 8 |
| Conway | 8b | Dec 21 – Jan 4 | Feb 15 – Mar 1 |
| Easley | 8a | Jan 7 – Jan 21 | Mar 4 – Mar 18 |
| Florence | 8b | Dec 25 – Jan 8 | Feb 19 – Mar 5 |
| Fort Mill | 8a | Jan 6 – Jan 20 | Mar 3 – Mar 17 |
| Fountain Inn | 8a | Jan 4 – Jan 18 | Mar 1 – Mar 15 |
| Gaffney | 8a | Jan 26 – Feb 9 | Mar 23 – Apr 6 |
| Goose Creek | 8b | Dec 13 – Dec 27 | Feb 7 – Feb 21 |
| Greenville | 8a | Jan 3 – Jan 17 | Feb 28 – Mar 14 |
| Greenwood | 8a | Jan 1 – Jan 15 | Feb 26 – Mar 12 |
| Greer | 8a | Jan 3 – Jan 17 | Feb 28 – Mar 14 |
| Hanahan | 9a | Dec 13 – Dec 27 | Feb 7 – Feb 21 |
| Hardeeville | 9a | Dec 8 – Dec 22 | Feb 2 – Feb 16 |
| Hilton Head Island | 9b | Dec 9 – Dec 23 | Feb 3 – Feb 17 |
| Irmo | 8b | Jan 16 – Jan 30 | Mar 13 – Mar 27 |
| James Island | 9a | Nov 12 – Nov 26 | Jan 7 – Jan 21 |
| Lexington | 8b | Dec 31 – Jan 14 | Feb 25 – Mar 11 |
| Mauldin | 8a | Jan 3 – Jan 17 | Feb 28 – Mar 14 |
| Moncks Corner | 8b | Dec 16 – Dec 30 | Feb 10 – Feb 24 |
| Mount Pleasant | 9a | Dec 19 – Jan 2 | Feb 13 – Feb 27 |
| Myrtle Beach | 8b | Dec 27 – Jan 10 | Feb 21 – Mar 7 |
| North Augusta | 8b | Dec 5 – Dec 19 | Jan 30 – Feb 13 |
| North Charleston | 9a | Dec 13 – Dec 27 | Feb 7 – Feb 21 |
| North Myrtle Beach | 8b | Dec 19 – Jan 2 | Feb 13 – Feb 27 |
| Orangeburg | 8b | Dec 19 – Jan 2 | Feb 13 – Feb 27 |
| Port Royal | 9a | Dec 9 – Dec 23 | Feb 3 – Feb 17 |
| Rock Hill | 8a | Jan 2 – Jan 16 | Feb 27 – Mar 13 |
| Simpsonville | 8a | Jan 4 – Jan 18 | Mar 1 – Mar 15 |
| Spartanburg | 8a | Jan 14 – Jan 28 | Mar 11 – Mar 25 |
| Summerville | 8b | Dec 28 – Jan 11 | Feb 22 – Mar 8 |
| Sumter | 8b | Dec 30 – Jan 13 | Feb 24 – Mar 10 |
| Tega Cay | 8a | Jan 6 – Jan 20 | Mar 3 – Mar 17 |
| West Columbia | 8b | Dec 31 – Jan 14 | Feb 25 – Mar 11 |
Calculated from each town's average (50%) frost dates, from the nearest NOAA station (1991–2020). Typical dates for the 2027 planting season, based on NOAA's 1991–2020 averages. They are long-term odds, not a forecast: always check your local forecast before planting. Zones: 2023 USDA Plant Hardiness Zone Map (USDA-ARS and Oregon State University). Not the official map; see planthardiness.ars.usda.gov.
See all frost dates in South Carolina, or the general guide to when to plant onions.
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