How to Grow Sweet Potatoes: From Slips to Harvest

Sweet potatoes are one of the most rewarding crops you can grow at home. A single planting of these vigorous, sprawling vines can produce a generous haul of nutritious tubers that store for months — and the lush, heart-shaped foliage looks beautiful tumbling out of a bed or container along the way. They're also remarkably low-maintenance once established. Here's everything you need to know to grow your own, from slips to harvest.

Sweet potatoes are not potatoes

Despite the name, sweet potatoes (*Ipomoea batatas*) aren't related to ordinary potatoes at all — they belong to the morning glory family. That matters for how you grow them: instead of planting tubers or seed, you grow sweet potatoes from slips, which are rooted sprouts grown from a mature tuber. They also love heat far more than regular potatoes do, making them a true warm-season crop.

Climate and timing: warmth is everything

Sweet potatoes need a long, warm growing season — typically 90–120 frost-free days — and they thrive in heat that would stress many other vegetables. Soil temperature is the key trigger.

Northern Hemisphere: plant slips in late spring to early summer, once soil has warmed to at least 18°C (65°F) and all frost risk has passed. In late May and June, much of the temperate Northern Hemisphere is reaching that point.

Southern Hemisphere: plant from mid to late spring into early summer (roughly October–December).

Warm climates (USDA zones 9–11 / subtropical and Mediterranean areas): an easy, long season — you can plant earlier and harvest a big crop.

Cooler climates (USDA zones 5–7 / cooler temperate areas): choose short-season varieties, warm the soil with black plastic mulch, and consider growing in containers you can place in the warmest, sunniest spot.

Always confirm your local last-frost date — slips set out into cold soil simply stall.

Growing your own slips

You can buy slips from a garden supplier, or grow your own from an organic sweet potato (conventional ones are sometimes treated to resist sprouting).

1. Suspend a healthy tuber half-submerged in a jar of water using toothpicks, or lay it in a tray of moist potting mix. 2. Keep it warm and bright. In a few weeks, leafy sprouts will emerge. 3. When each sprout is 15–20 cm (6–8 in) long, twist it off and stand it in water for a few days until roots form. 4. Once well-rooted, your slips are ready to plant.

Start this process 6–8 weeks before your intended planting date.

Soil and bed preparation

Sweet potatoes form their tubers in the soil, so loose, well-draining ground gives the best results.

Soil type: light, sandy-to-loamy soil is ideal. Heavy clay produces stunted or oddly shaped tubers — if that's what you have, grow in raised beds or large containers instead.

pH: slightly acidic, around 5.5–6.5.

Fertility: moderate. Avoid heavy nitrogen, which drives leafy vine growth at the expense of tubers. Work in some compost, but go easy.

Mounds: plant into ridges or mounds about 20–25 cm (8–10 in) high. This warms the soil, improves drainage, and gives tubers room to develop.

Planting your slips

Set slips 30 cm (12 in) apart, in rows 90 cm (3 ft) apart, planting them deep enough to bury the lower stem with only the top leaves showing. Water them in well. They may wilt for a day or two — this is normal, and they'll perk up as roots take hold.

Growing in containers

Sweet potatoes adapt beautifully to containers, which is great for cooler climates and small spaces. Use a large pot or grow bag of at least 40 litres (10 gallons) per plant, fill with a free-draining mix, and place it in full sun. The trailing vines look ornamental spilling over the edge.

Care through the season

Sun: full sun, at least 6–8 hours a day.

Water: keep soil consistently moist while plants establish and during tuber formation, roughly 2.5 cm (1 in) per week. Ease off watering in the last 3–4 weeks before harvest to firm up the tubers and improve storage life.

Weeding: weed early on; once the vines spread, they form a dense canopy that smothers most weeds.

Vines: if vines root at the leaf nodes where they touch the soil, lift them occasionally so the plant channels energy into the main tubers rather than scattering small ones.

Pests and problems

Sweet potatoes are relatively trouble-free, but watch for:

Sweet potato weevils: the main pest in warm regions. Use certified slips, rotate crops, and harvest promptly.

Voles and rodents: can nibble tubers underground; container growing sidesteps this.

Scurf or rots: usually linked to poorly drained soil — raised mounds and good drainage prevent most issues.

Harvesting

Tubers are usually ready 90–120 days after planting, often signalled by yellowing leaves. Harvest before the first frost, since cold damages the tubers.

1. Cut back the vines, then loosen the soil gently with a fork well away from the centre of the plant to avoid spearing tubers. 2. Lift carefully by hand — the skins are delicate when freshly dug. 3. Brush off soil but don't wash them yet.

Curing for sweetness and storage

This step is what transforms a freshly dug sweet potato into the sweet, mellow vegetable you want. Curing heals the skin and converts starches to sugars.

Keep the tubers somewhere warm and humid — ideally 27–32°C (80–90°F) at high humidity — for about 7–10 days. A warm spot covered loosely to hold humidity works for home growers.

After curing, store at a cool room temperature of around 13–15°C (55–60°F). Never refrigerate raw sweet potatoes, which causes a hard core and off flavours.

Properly cured, sweet potatoes keep for several months — and actually taste better after a few weeks in storage.

Share the abundance

A handful of slips can yield far more sweet potatoes than one household can use, and they store so well that you'll have plenty to spare through autumn and winter. That makes them a perfect crop for swapping and sharing — a basket of homegrown sweet potatoes is a genuinely generous gift to a neighbour.

Want to share your harvest and connect with growers nearby? Join Locavori today and become part of a community that grows, swaps, and shares fresh food together.