How to Grow Sweet Potatoes: Slips, Care & Harvest

Quick answer

Plant slips 1–2 weeks after last frost (UNH) after soil warms to about 65°F (UMD). Bedding roots to planting takes about 6 weeks — start slips about last frost −5 to −4. Space about 12 inches in the row and 40 inches between rows on ridges (UMD). Dig before frost; if vines freeze, dig immediately.

Sweet potato storage roots (Ipomoea batatas)
Kostka Martin, CC0, via Wikimedia Commons · source · license

Sweet potato at a glance

PlantStart slips: 5–4 wk before last frost; Plant slips: 1–2 wk after last frost
SpacingUMD: about 12 inches between plants in the row and 40 inches between rows.
Days to harvest85–120 days (UMD)
-6-5-4-3-2-1LF+1+2+3
■ Start indoors   ■ Plant out   ■ Harvest
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Updated

Planting dates for your ZIP: the ZIP planting planner counts each window from your local frost dates.

Organic pests and diseases: see also organic pest control. Use any product as the label directs.

Sweet potato (Ipomoea batatas) — not a true yam (Dioscorea). Very tender warm-season storage-root crop.

Sweet potato storage roots
Sweet potato storage roots. Photo: Kostka Martin, Wikimedia Commons, CC0 (resized).

Planting timing

UNH: plant slips in the garden 1–2 weeks after last frost. (UNH) UMD: plant sprouted shoots (slips) after soil warms to about 65°F / after frost danger; “the process from bedding to planting takes six weeks.” (UMD) Planner: Plant slips last frost +1 to +2; Start slips (bed roots) last frost −5 to −4. Slip bedding takes about 6 weeks from bedding to planting (UMD).

Depth and spacing

UMD: about 12 inches between plants in the row and 40 inches between rows. Plant on ridges for warmer soil, drainage, and easier harvest. Keep freshly planted slips well watered.

Sun, soil and water

UMD: best in light sandy soils; clay OK with organic matter. Medium fertility — compost before planting; omit fertilizer product rates. Uniform moisture; drought-sensitive the first 50–60 days; do not keep saturated (rot).

Care

Hand weed until vines shade the bed. Organic mulch where weed pressure is high (UMD). Rotate crops (NC State).

Harvest and curing

UMD: about 85–120 days; check size after 80–85 days; harvest before frost. If vines are frost-killed, dig immediately (decay moves into roots). Cure about 1 week in a warm porch/garage, then store cool and dry. Commercial cure is warmer/humid; home partial cure is OK.

Pests and diseases (organic)

Voles: cultural exclusion / habitat reduction (UMD). Scurf: certified stock; wash purchased roots; sanitation. Flea beetles / thrips: rotate each year (NC State).

Related: ZIP planner · organic pest control · all grow guides

Frequently asked questions

When do I plant sweet potato slips?

Last frost +1 to +2 (UNH); soil ~65°F / after frost (UMD).

How long to grow slips?

About 6 weeks from bedding to plant-out (UMD) → bed at last frost −5 to −4.

Frost hit the vines — what now?

Dig roots immediately (UMD).

More grow guides: All grow guides

Sources