Sweet potato · last checked 2026-09-27
When to harvest sweet potatoes: first frost, curing, slips
Sweet potatoes are grown from rooted sprouts called slips and need a long, warm season. The roots are dug in fall and cured before storage.
Each line names the Extension service it comes from and links to their page. Where the two services give different spacing, both are shown.
When to plant
- Illinois Extension says slips go out as soon as the soil has warmed after the last frost, to give the longest warm season. Sweet Potato (Home Vegetable Gardening) · checked 2026-09-27
- Clemson Cooperative Extension says sweet potatoes are planted well after the last chance of frost; homegrown slips take about two weeks to sprout and about ten more days to root. Sweetpotato (HGIC fact sheet) · checked 2026-09-27
Soil temperature
- Clemson Cooperative Extension says to wait until the soil is above 65 °F before planting. Sweetpotato (HGIC fact sheet) · checked 2026-09-27
State planting dates
| Who says | Region | Planting window | Source |
|---|---|---|---|
| Clemson Cooperative Extension says | South Carolina, Piedmont counties | Spring: May 1 to June 15. Fall planting not recommended. | Sweetpotato (HGIC fact sheet) · checked 2026-09-27 |
| Clemson Cooperative Extension says | South Carolina, Coastal counties | Spring: April 15 to June 15. Fall planting not recommended. | Sweetpotato (HGIC fact sheet) · checked 2026-09-27 |
Spacing
- Illinois Extension says slips are set 12 to 18 inches apart, ideally on a wide raised ridge about 8 inches high. Sweet Potato (Home Vegetable Gardening) · checked 2026-09-27
- Clemson Cooperative Extension says rows are 3 feet apart with 8 to 12 inches between slips, planted 3 to 4 inches deep. Sweetpotato (HGIC fact sheet) · checked 2026-09-27
Harvest
- Illinois Extension says the main crop is dug around the first fall frost; stop watering in the last three to four weeks, and cure the roots at about 85 °F and high humidity for 10 to 14 days, then store near 55 °F. Sweet Potato (Home Vegetable Gardening) · checked 2026-09-27
- Illinois Extension says if frost hits the vines, cut them away from the roots right away and dig as soon as you can. Sweet Potato (Home Vegetable Gardening) · checked 2026-09-27
- Clemson Cooperative Extension says common varieties are listed at roughly 90 to 135 days to maturity; Beauregard, at 90 to 100 days, is named as the quickest. Sweetpotato (HGIC fact sheet) · checked 2026-09-27
Unless a line says otherwise, weeks are counted from the average last spring frost where you live. Find that date through your state’s Extension service. See how these pages are put together.
Other crops: Blueberry, Broccoli, Garlic, Okra, Potato, Pumpkin, Strawberry, Tomato.