Sweet potatoes are a warm-weather crop. They require a long, hot growing season.
- Sweet potatoes are grown from rooted cuttings, called “slips” or “draws”. Slips are best started indoors from sweet potato tubers. Slips stated indoors take about 12 weeks to reach transplant size.
- Transplant sweet potato slips into the garden after all danger of frost is past in spring. Sweet potato tubers form over a long, frost-free growing season—about 150 to 175 days from starting slips.
Sweet Potato Sowing and Planting Tips:
- Grow sweet potatoes from slips or cutting (also called “draws” or “seed roots”). To grow slips, begin about 12 weeks before they will be transplanted outdoors. Set a sweet potato in a glass jar half-filled with water, submerging one-third of the tuber. Place the tuber in a warm, sunny location until it sprouts. When sprouts are 6 inches (15 cm) long, pull them off the potato and set them in water or damp sand until they root.
- Slips can be planted out in the garden 2 to 4 weeks after the last frost in spring after the soil and nighttime temperatures are greater than 60°F (16°C).
- Sweet potatoes require a growing season of 120 frost-free days once they are in the garden. They cannot tolerate frost.
- Set the cutting 2 to 3 inches (5-7.5 cm) deep. With a rake make a ridge of soil 6 to 10 inches (15-20 cm) wide. Plant slips into the ridge about 12 inches (30 cm) apart. Set slips so that only the stem tips and leaves are exposed.
- Keep the soil moist—not wet–until newly set slips begin to grow.
- Grow sweet potatoes in well-drained, light, sandy loam amended with aged compost.
- Add fish emulsion to the soil at planting time. Too much nitrogen produces leafy growth at the expense of tubers.
- Sweet potatoes prefer a soil pH between 5.0 and 6.5.
- Grow sweet potatoes in a sunny location.
- Common pest enemies are aphids, flea beetles, leafhoppers, and wireworms.
Container Growing Sweet Potatoes: Semi-trailing sweet potato varieties can be grown in containers draping over the edges. Use a container 30 inches (76 cm) deep and 20 inches (51 cm) across.
Sweet Potato Planting Calendar
- 12-10 weeks before the last frost in spring: start slips or draws indoors.
- 2-4 weeks after the last frost in spring: transplant rooted cutting or slips to the garden.
Recommended Sweet Potato Varieties
There are two classes of sweet potatoes:
- Soft, sugary yellow-orange flesh: varieties include ‘Allgood’. ‘Beauregard’, ‘Centennial’, ‘Jewel’, ‘Vardamen’.
- Firm, dry, whitish flesh: ‘Onokeo’, ‘Waimanalo Red’, ‘Yellow Jersey’.
Botanical Name: Ipomea batatas
Sweet potatoes are a member of the Convolvulaceae or morning glory family.
