Sweet potatoes do not like weed competition, so lightly till the bed once or twice starting 2 weeks prior to planting. The slips may be planted directly in the ground or in raised ridges of soil 8” high to help them warm up faster and to improve drainage.
Plant after the danger of frost has passed, when the soil is as least 65°F. Place slips 3” deep, spaced 12” apart. For vining varieties (the most common), rows should be about at least 3’-4’ apart. Rows can be closer for bush varieties. Slips will often arrive wilted or show significant transplant shock. Don’t worry! Plant as normal and after a week or so they’ll perk up.
Sweet potatoes can be slow starters so keep the field weeded until the plants begin to spread. Otherwise, leave them alone. Extra fertilizer tends to promote leaf growth but not increased root yields.
Greens can be harvested throughout the season with light clipping from each plant. Stop watering 3 weeks prior to root harvest to keep mature tubers from splitting. Dig up potatoes where the slip was originally planted. Harvest can begin in early fall until no later than first frost.
Curing and Storage
Sweet potatoes should be cured to convert the starch to sugar and to toughen the outer skin for long-term storage. Store them in a warm room at 80°F to 85°F with high humidity for 10 days. Afterwards, keep them in a dark, cool location in a ventilated mouse-proof container.
Deer and groundhogs enjoy eating the young greens while wireworms and nematodes can affect the tubers. Rotating crop location can reduce soil-borne pests.