How to Grow Sweet Potatoes

What slips are and how to get them

Sweet potatoes are not grown from seed or from cut seed pieces like regular potatoes. They are grown from 'slips,' which are leafy sprouts that grow from a sprouting sweet potato root, each with the start of its own roots.

You can buy slips or make your own. Utah State Extension describes placing roots about an inch apart in a warm bed and covering with 2 inches of sand or light soil, holding a soil temperature of 70 to 80°F; the slips are ready in about 6 weeks, once they are rooted and 6 to 8 inches tall. Twist or snap the slips off the mother root and plant them.

This warm start is why sweet potatoes feel exotic to grow in cool regions. If you are short on a warm early season, the slips do most of the waiting for you indoors while the garden warms up.

Warmth, ridges, and a long season

Sweet potatoes are tropical and heat-loving. They need about 4 to 5 months of warm days and warm nights to size up, and plants can be damaged by temperatures below 50°F, so plant slips only after all danger of frost has passed and the soil has warmed.

Plant on raised ridges. Utah State recommends forming ridges 8 to 10 inches tall and setting slips 12 inches apart in rows 36 to 48 inches apart. A ridge drains better and, importantly, warms earlier and stays warmer than flat ground, which suits a heat-lover. Black plastic mulch can push early growth by trapping soil heat.

From there they largely take care of themselves, sending out sprawling vines. Depending on variety, expect roughly 90 to 135 days to maturity. For exact planting dates and in-row spacing, see the sweet potato calculators.

Harvest before frost — then cure

Time the harvest to the end of the warm season. Dig when the foliage starts to turn yellow or after the first frost damages the leaves, but get the roots out before the soil freezes, since frozen soil ruins them. Dig carefully with a fork well away from the crown, because the skins are thin and bruise easily at harvest.

Sweet potatoes out of the ground are firm and starchy, not yet sweet. That is normal. Handle them gently and set them aside for curing, which is what converts starch to sugar and heals the skin for storage.

Curing is a distinct step done warm and humid, and then long-term storage is kept cool and dry. Because it is easy to get wrong, it has its own guide, linked below.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

• Utah State University Extension — How to Grow Sweet Potatoes in Your Garden — Sweet potatoes are grown from slips (sprouts from the root); start slips by placing roots about 1 inch apart in a bed covered with 2 inches of sand or light soil at 70-80°F, ready in about 6 weeks when rooted and 6-8 inches tall; the crop needs about 4-5 months of warm conditions; plant slips after danger of frost, spacing 12 inches apart in rows 36-48 inches apart on 8-10 inch raised ridges; varieties range 90-135 days; harvest when foliage turns yellow or after the first frost damages leaves but before the soil freezes; roots are cured 1-2 weeks at 80°F then stored cool (50-55°F).
• Illinois Extension — Sweet Potato (Home Vegetable Gardening) and Good Growing — Sweet potatoes are a tropical plant grown from slips and usually need four to five months of warm day and night temperatures for optimal growth; plants can be damaged by temperatures below 50°F; set plants 12 to 18 inches apart on a wide raised ridge about 8 inches high, which dries and warms earlier than flat ground; black plastic mulch can speed early-season growth by warming the soil.

Keep going