Sweet Potato Plant Starting Tips -- Harvest to Table

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.

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Sweet potato cutting rooted in water — Sweet potato cutting or slip roots in water.

Plant sweet potato sprouts (called “slips”) in the garden 2 to 3 weeks after the last frost. Night temperatures must stay warmer than 60°F (16°C) and the soil temperature should be at least 65°F (18°C) for sweet potatoes to thrive.

Start purchased slips or sprouts on your own about 6 to 8 weeks before setting sprouts in the garden. Short-season gardeners can start earlier and protect plants from late frosts.

Sweet potatoes grow best in long-season regions (150 to 160 days of frost-free weather) where summers are hot but not excessively rainy. The optimal temperature range for best growth is 70°to 85°F (21°-29°C).

Sweet potatoes can take as many as 170 days to reach maturity, but some varieties can be harvested in about 100 days. Sweet potato tubers often double in size in the final month. Tubers of good quality can be harvested immaturely. Harvest mature tuber immediately after the first frost.

Table of Contents

How to start slips

Young sweet potato plants are called slips. You can start slips by setting a whole sweet potato tuber in a moist rooting medium. Keep the tubers warm. Sprouts will grow from the tuber and root. When they are 4 to 8 inches (10-20cm) tall, gently pull them from the mother tuber. You can grow them in individual pots until it is warm enough to plant them in the garden.

Slips or “seedlings” growing from a mother tuber

Planting sweet potatoes in the garden

To plant sweet potato slips in the garden create a furrow 2 inches (5cm) deep and 12 inches (30cm) wide and fill it with aged compost or commercial planting mix. Ridge soil 10 inches (25cm) high over the furrow. Insert the slips into the soil 2 to 5 inches (5-12cm) deep spaced 15 inches (38cm) apart along the ridge.

Sweet Potato planting details

Planting depth: Set slips 4 to 8 inches deep
Space between plants: 15 inches
Days to harvest: 100 to 170
Storage period: 4-6 months
Suggested varieties: Allgood, Beauregard, Centennial, Jewel, Vardamen

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

10-12 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.

Sweet potatoes require a growing season of 120 frost-free days once they are in the garden. They cannot tolerate frost.

Sweet potato planting dates

(These dates are for the Northern Hemisphere)

Average date of the last frost	Planting dates
Jan. 30	Feb. 15-May 15
Feb. 8	Mar. 1-May 15
Feb. 18	Mar. 20-June 1
Feb. 28	Apr. 1-June 1
Mar. 10	Apr. 10-June 1
Mar. 20	Apr. 20-June 1
Mar. 30	May 1-June 1
Apr. 10	May 10-June 10
Apr. 20	May 20-June 10
Apr. 30	Season is too short
May 10	Season is too short
May 20	Season is too short
May 30	Season is too short
June 10	Season is too short

Sweet potato recommended 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.

More tips: How to Grow Sweet Potatoes

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