Growing sweet potatoes: timing, spacing and costs by zone

When to plant

Sweet potatoes: warm-season, will not take a frost. Plant when soil reaches 75–90°F. Dates below are averages worked out from each zone's frost dates — check your own field.

• Zone 6b (Boone NC): set out May 8 – May 29. First picking around August 23 – September 20.
• Zone 7b (Raleigh): set out April 22 – May 13. First picking around August 7 – September 4.
• Zone 8b (Charleston SC): set out March 29 – April 19. First picking around July 14 – August 11.
• Zone 9a (Gainesville FL): set out March 11 – April 1. First picking around June 26 – July 24.

Setting it up

Grow as transplants, started about 6 weeks before last frost. Space plants 12 inches apart in rows 42 inches apart, about 4 inch deep. Expect roughly 100 days to first harvest.

Field notes

Set slips on 6–8 inch hills for better tuber shape. Cure at 85°F and 85% humidity for 7–10 days after harvest.

How it fits each zone

• Zone 6b: challenging — Sweet potatoes needs a long season and this zone averages just 167 frost-free days. Start early, use black plastic, and plan for row cover on shoulder-season frosts.
• Zone 7b: excellent — Sweet potatoes is well suited to Zone 7b. Standard planting dates work with minor adjustments for microclimates.
• Zone 8b: excellent — Sweet potatoes is well suited to Zone 8b. Standard planting dates work with minor adjustments for microclimates.
• Zone 9a: excellent — Sweet potatoes is well suited to Zone 9a. Standard planting dates work with minor adjustments for microclimates.

What it costs per acre

• Sweetpotato — 2025 (NC State Extension — Agricultural & Resource Economics, 2025): about $2,746 per acre in transcribed costs.

These are published budgets, not your costs. Plug your own numbers into the breakeven calculator before you commit ground.

Before you plant

Line up who will buy it and at what price before seed goes in the ground. See the planting calendar for your exact zone.