Frost Dates for Saint Helena Island, SC 29920
Last spring frost March 9 · First fall frost December 7 · 273 frost-free days · USDA Zone 9b
ZIP 29920 has about 10,600 people.
Very long season: 273 frost-free days. Spring frost risk spans February 13–April 3 (49 days). Fall frost risk spans November 10–January 4 (55 days).
Frost probability for 29920
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | April 3 | March 9 | February 13 |
| Fall (first frost) | November 10 | December 7 | January 4 |
Dates come from NOAA 1971–2000 freeze probabilities at EDISTO BEACH SP (28.6 km away); the 50% date is the median year.
Which crops fit a 273-day season in Saint Helena Island
In Saint Helena Island (273 frost-free days, a very long season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Feb 2 | Mar 23–Mar 30 | 231 | fits: 80 days to maturity, 231 available after Mar 23. | Aug 7 |
| Pepper | Jan 26 | Mar 23–Mar 30 | 231 | fits: 75 days to maturity, 231 available after Mar 23. | Aug 12 |
| Lettuce | Jan 12 | Feb 9–Feb 16 | 308 | two-plantings: Plant Feb 9 and again by Oct 16; both mature before Dec 14. | Oct 16 |
| Carrots | — | Feb 16–Feb 23 | 315 | fits: 70 days to maturity, 315 available after Feb 16. | Oct 5 |
| Cucumber | Feb 16 | Mar 23–Mar 30 | 245 | two-plantings: Plant Mar 23 and again by Sep 10; both mature before Nov 23. | Sep 10 |
| Beans | — | Mar 16–Mar 30 | 259 | two-plantings: Plant Mar 16 and again by Sep 17; both mature before Nov 30. | Sep 17 |
| Peas | — | Jan 12–Mar 23 | 336 | fits: 65 days to maturity, 336 available after Jan 12. | Sep 26 |
| Zucchini | Feb 23 | Mar 23–Mar 30 | 245 | two-plantings: Plant Mar 23 and again by Sep 15; both mature before Nov 23. | Sep 15 |
| Onion | Dec 15 | Feb 9–Feb 23 | 308 | fits: 100 days to maturity, 308 available after Feb 9. | — |
| Spinach | — | Jan 12–Mar 2 | 350 | two-plantings: Plant Jan 12 and again by Nov 4; both mature before Dec 28. | Nov 4 |
| Kale | Dec 29 | Feb 9–Feb 23 | 322 | two-plantings: Plant Feb 9 and again by Oct 20; both mature before Dec 28. | Oct 20 |
| Broccoli | Jan 12 | Feb 9–Feb 23 | 308 | fits: 80 days to maturity, 308 available after Feb 9. | Sep 11 |
| Cabbage | Jan 12 | Feb 9–Feb 23 | 322 | fits: 70 days to maturity, 322 available after Feb 9. | Oct 5 |
| Radish | — | Jan 12–Apr 6 | 336 | two-plantings: Plant Jan 12 and again by Nov 5; both mature before Dec 14. | Nov 5 |
| Beets | — | Jan 12–Apr 6 | 336 | two-plantings: Plant Jan 12 and again by Oct 6; both mature before Dec 14. | Oct 6 |
| Potatoes | — | Feb 23–Mar 2 | 294 | fits: 90 days to maturity, 294 available after Feb 23. | — |
| Garlic | — | Dec 7 | 378 | overwinter: Plant Dec 7 to Dec 28; harvest the following summer. | Dec 28 |
| Strawberry | — | Feb 2–Mar 30 | 329 | perennial: A perennial: plant Feb 2; it fruits from the following year and keeps producing for several years. | — |
| Corn | Feb 9 | Mar 16–Mar 23 | 245 | fits: 75 days to maturity, 245 available after Mar 16. | Aug 19 |
| Pumpkin | Feb 23 | Mar 23–Mar 23 | 238 | fits: 100 days to maturity, 238 available after Mar 23. | Jul 25 |
| Cauliflower | Jan 26 | Mar 2–Mar 16 | 287 | fits: 75 days to maturity, 287 available after Mar 2. | Sep 16 |
| Swiss Chard | Jan 12 | Feb 23–Feb 23 | 294 | two-plantings: Plant Feb 23 and again by Oct 6; both mature before Dec 14. | Oct 6 |
| Arugula | — | Jan 12–Apr 6 | 350 | two-plantings: Plant Jan 12 and again by Nov 4; both mature before Dec 28. | Nov 4 |
| Brussel Sprouts | Jan 12 | Feb 9–Feb 23 | 322 | fits: 100 days to maturity, 322 available after Feb 9. | Sep 5 |
| Butternut Squash | Feb 23 | Mar 23–Mar 30 | 238 | fits: 100 days to maturity, 238 available after Mar 23. | Jul 25 |
| Eggplant | Jan 19 | Mar 23–Mar 30 | 231 | fits: 70 days to maturity, 231 available after Mar 23. | Aug 17 |
| Okra | Feb 9 | Mar 16–Mar 23 | 252 | two-plantings: Plant Mar 16 and again by Sep 15; both mature before Nov 23. | Sep 15 |
| Basil | Feb 2 | Mar 30–Mar 30 | 238 | two-plantings: Plant Mar 30 and again by Sep 10; both mature before Nov 23. | Sep 10 |
| Cilantro | — | Feb 9–Mar 2 | 308 | two-plantings: Plant Feb 9 and again by Oct 11; both mature before Dec 14. | Oct 11 |
| Parsley | Dec 29 | Mar 16–Mar 23 | 273 | fits: 70 days to maturity, 273 available after Mar 16. | Sep 21 |
| Celery | Dec 29 | Mar 16–Mar 30 | 273 | fits: 120 days to maturity, 273 available after Mar 16. | Aug 2 |
| Scallions | Dec 29 | Feb 9–Feb 23 | 322 | two-plantings: Plant Feb 9 and again by Oct 15; both mature before Dec 28. | Oct 15 |
| Turnip | — | Feb 9–Feb 23 | 322 | two-plantings: Plant Feb 9 and again by Oct 25; both mature before Dec 28. | Oct 25 |
| Kohlrabi | — | Jan 26–Feb 9 | 336 | two-plantings: Plant Jan 26 and again by Oct 20; both mature before Dec 28. | Oct 20 |
| Bok Choy | Feb 9 | Mar 2–Mar 9 | 287 | two-plantings: Plant Mar 2 and again by Oct 16; both mature before Dec 14. | Oct 16 |
| Collards | Dec 29 | Feb 9–Feb 23 | 322 | two-plantings: Plant Feb 9 and again by Oct 15; both mature before Dec 28. | Oct 15 |
| Cantaloupe | Feb 23 | Mar 23–Mar 30 | 231 | fits: 85 days to maturity, 231 available after Mar 23. | Aug 2 |
| Chives | Dec 15 | Mar 16–Mar 23 | 287 | fits: 90 days to maturity, 287 available after Mar 16. | — |
| Dill | — | Jan 12–Apr 6 | 336 | two-plantings: Plant Jan 12 and again by Oct 6; both mature before Dec 14. | Oct 6 |
| Oregano | Dec 29 | Mar 16–Mar 23 | 287 | fits: 80 days to maturity, 287 available after Mar 16. | — |
| Rosemary | Dec 15 | Mar 16–Mar 23 | 273 | fits: 80 days to maturity, 273 available after Mar 16. | — |
| Sage | Jan 12 | Mar 16–Mar 23 | 287 | fits: 75 days to maturity, 287 available after Mar 16. | — |
| Thyme | Dec 29 | Mar 16–Mar 23 | 287 | fits: 90 days to maturity, 287 available after Mar 16. | — |
| Calendula | Jan 26 | Feb 23–Mar 9 | 294 | two-plantings: Plant Feb 23 and again by Oct 11; both mature before Dec 14. | Oct 11 |
| Cosmos | Feb 9 | Mar 9–Mar 23 | 259 | two-plantings: Plant Mar 9 and again by Sep 10; both mature before Nov 23. | Sep 10 |
| Lavender | Dec 15 | Mar 9–Mar 23 | 294 | fits: 90 days to maturity, 294 available after Mar 9. | — |
| Marigolds | Jan 26 | Mar 9–Mar 16 | 259 | two-plantings: Plant Mar 9 and again by Sep 20; both mature before Nov 23. | Sep 20 |
| Melons | Feb 23 | Mar 23–Mar 30 | 231 | fits: 85 days to maturity, 231 available after Mar 23. | Aug 2 |
| Mint | — | Mar 9–Mar 23 | 294 | fits: 90 days to maturity, 294 available after Mar 9. | — |
| Nasturtiums | Feb 9 | Mar 9–Mar 16 | 259 | two-plantings: Plant Mar 9 and again by Sep 15; both mature before Nov 23. | Sep 15 |
| Pole Beans | — | Mar 16–Mar 30 | 252 | fits: 65 days to maturity, 252 available after Mar 16. | Sep 5 |
| Spaghetti Squash | Feb 23 | Mar 23–Mar 30 | 238 | fits: 90 days to maturity, 238 available after Mar 23. | Aug 4 |
| Sunflowers | — | Mar 9–Mar 23 | 259 | fits: 70 days to maturity, 259 available after Mar 9. | Aug 31 |
| Tomatillos | Jan 12 | Mar 16–Mar 23 | 238 | fits: 75 days to maturity, 238 available after Mar 16. | Aug 12 |
| Watermelon | Feb 23 | Mar 16–Mar 23 | 238 | fits: 80 days to maturity, 238 available after Mar 16. | Aug 7 |
| Yellow Squash | Feb 23 | Mar 23–Mar 30 | 245 | two-plantings: Plant Mar 23 and again by Sep 15; both mature before Nov 23. | Sep 15 |
| Zinnias | Feb 9 | Mar 9–Mar 23 | 259 | two-plantings: Plant Mar 9 and again by Sep 10; both mature before Nov 23. | Sep 10 |
Month by month in Saint Helena Island
| Month | What to do |
|---|---|
| January | Start indoors: Broccoli (Jan 12), Brussel Sprouts (Jan 12), Cabbage (Jan 12), Lettuce (Jan 12), Sage (Jan 12), Swiss Chard (Jan 12), +6 more. Direct sow from: Arugula (Jan 12), Beets (Jan 12), Dill (Jan 12), Peas (Jan 12), Radish (Jan 12), Spinach (Jan 12), +1 more. |
| February | Start indoors: Basil (Feb 2), Tomato (Feb 2), Bok Choy (Feb 9), Corn (Feb 9), Cosmos (Feb 9), Nasturtiums (Feb 9), +11 more. Direct sow from: Cilantro (Feb 9), Turnip (Feb 9), Carrots (Feb 16), Potatoes (Feb 23). Transplant from: Broccoli (Feb 9), Brussel Sprouts (Feb 9), Cabbage (Feb 9), Collards (Feb 9), Kale (Feb 9), Lettuce (Feb 9), +4 more. Plant: Strawberry (Feb 2). |
| March | Direct sow from: Sunflowers (Mar 9), Beans (Mar 16), Pole Beans (Mar 16). Transplant from: Bok Choy (Mar 2), Cauliflower (Mar 2), Cosmos (Mar 9), Lavender (Mar 9), Marigolds (Mar 9), Mint (Mar 9), +25 more. Last frost around March 9. |
| April | Frost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini. |
| May | Succession plant lettuce and greens. Keep beds weeded and watered consistently. |
| June | Harvest regularly to encourage production. Monitor for pests and disease. |
| July | Last sowing dates: Butternut Squash (Jul 25), Pumpkin (Jul 25). |
| August | Last sowing dates: Cantaloupe (Aug 2), Celery (Aug 2), Melons (Aug 2), Spaghetti Squash (Aug 4), Tomato (Aug 7), Watermelon (Aug 7), +5 more. |
| September | Last sowing dates: Brussel Sprouts (Sep 5), Pole Beans (Sep 5), Basil (Sep 10), Cosmos (Sep 10), Cucumber (Sep 10), Zinnias (Sep 10), +10 more. |
| October | Last sowing dates: Cabbage (Oct 5), Carrots (Oct 5), Beets (Oct 6), Dill (Oct 6), Swiss Chard (Oct 6), Calendula (Oct 11), +8 more. |
| November | Last sowing dates: Arugula (Nov 4), Spinach (Nov 4), Radish (Nov 5). |
| December | Start indoors: Chives (Dec 15), Lavender (Dec 15), Onion (Dec 15), Rosemary (Dec 15), Celery (Dec 29), Collards (Dec 29), +5 more. Direct sow from: Garlic (Dec 7). First frost around December 7. Last sowing dates: Garlic (Dec 28). |
Frequently Asked Questions
What is the last frost date for Saint Helena Island, SC (ZIP 29920)?
The median last spring frost date for Saint Helena Island, SC (ZIP code 29920) is around March 9. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before February 13; one in ten it runs past April 3.
What is the first fall frost date in Saint Helena Island, SC?
The median first fall frost date for Saint Helena Island, SC is around December 7. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around November 10 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Saint Helena Island, SC?
The frost-free growing season in Saint Helena Island is about 273 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Saint Helena Island (273 frost-free days, a very long season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Saint Helena Island, SC?
Saint Helena Island, SC is in USDA hardiness zone 9b (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Saint Helena Island, SC?
Start tomatoes indoors Feb 2 and plant out Mar 23 in Saint Helena Island. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Saint Helena Island?
Two: plant Feb 9 and again by Oct 16; both mature before Dec 14.
When do I plant garlic in Saint Helena Island?
Dec 7 to Dec 28; it overwinters and is ready the following summer.
Can I get two tomato crops in Saint Helena Island?
Yes: plant out Mar 23 for a summer crop, and set out a second round of transplants by Aug 7 for a fall crop.
Nearby and related
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- Frost dates for Okatie, SC 29909 (17.9 mi)
- Frost dates for Bluffton, SC 29910 (21.8 mi)
- Frost dates for Ridgeland, SC 29936 (25.7 mi)
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