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Sweet potato

Ipomoea batatas

A heat-loving vine grown for sweet roots and edible leaves. Despite the name, it isn't a potato: it's in the morning glory family, not the nightshade family. It grows well in sandy Southern soils with little care.

Growing facts

Scientific name
Ipomoea batatas
Origin
Central and South America
Plant size
Sprawling vines 6–15 ft long, a few inches to 1 ft tall; bush types are compact
Growth rate
Fast
Sun
Full sun
Soil
Loose, sandy, well-drained soil; heavy soil and too much nitrogen give few, misshapen roots
Soil pH
5.5–6.5
Pollination
Not needed; grown from slips (sprouts) for the roots
Cold hardiness
Killed by frost; roots are damaged below 50°F
USDA zones
Grown as a warm-season annual; perennial in 10–11
Harvest
90–120 days from planting slips
When to plant (zones 9–11)
Mar–Jun
When to plant (zones 5–8)
May–Jun
Water
About every 5 days once established, without rain; more in heat, in pots and while young
Feeding
About every 45 days
Taste
Sweet and earthy; orange types are moist, white and purple types drier and starchier
Nutrition
Orange types are very rich in beta-carotene (vitamin A), with fiber and potassium

Is sweet potato safe to eat? Edible and toxic parts

What you can eat

  • Roots, cooked
  • Young leaves and shoot tips, cooked as greens

Toxic parts and cautions

  • Good to know: It isn't a potato. Unlike potato and tomato leaves, sweet potato leaves are a safe, common cooked green.
  • Good to know: Ornamental sweet potato vines from garden centers are bred for leaf color and may have been sprayed with products not meant for food crops; don't eat them.

Pets: Cooked, plain sweet potato is a common treat for dogs. Raw chunks are hard to digest and can be a choking hazard.

How to eat and enjoy sweet potato

  • Baked, roasted or mashed
  • Sweet potato pie
  • Fries and chips
  • Stir-fried leaves with garlic (Southeast Asia, Africa)
  • Steamed purple sweet potatoes (Okinawa, Hawaii)

When it's ripe

Dig when the leaves start to yellow, or by the variety's days to harvest; dig carefully, as the skin bruises easily. Cure the roots in a warm (80–85°F), humid spot for a week or two; this turns starch to sugar and heals scrapes.

Storing it

After curing, store in a cool, dry spot around 55–60°F for months. Don't refrigerate raw roots; cold makes the centers hard and off-tasting.

Sweet potato varieties (6)

  • Beauregard

    The most widely grown sweet potato in the U.S.: copper skin, deep orange flesh.

    Origin: Louisiana · Taste: Sweet, moist

    Productive and dependable.

  • Covington

    A rose-skinned, orange-fleshed sweet potato with uniform roots.

    Origin: North Carolina · Taste: Sweet, moist

    Stores well.

  • Georgia Jet

    A fast-maturing, red-skinned, orange-fleshed sweet potato.

    A good choice for short seasons in the North.

  • Murasaki · also Murasaki-29

    A purple-skinned sweet potato with white flesh.

    Taste: Dry, nutty, chestnut-like

  • O'Henry · also OHenry

    A cream-fleshed sweet potato with tan skin.

    Taste: Mild, dry, less sweet

  • Vardaman

    A bush-type sweet potato with short vines and dark-purple young leaves.

    Origin: Mississippi

    Good for small gardens and containers.

Pests and diseases to watch for

  • Scale insects

    Small bumps, waxy or shell-like, on stems and leaf veins; sticky honeydew and black sooty mold below.

    What to do: Scrub small colonies off with a soft brush.

  • Mealybugs

    White cottony clusters in leaf joints, under leaves and on fruit stems; honeydew and sooty mold.

    What to do: Blast off with a strong spray of water.

  • Aphids

    Clusters of tiny soft insects on new shoots; leaves curl and get sticky.

    What to do: Spray off with water.

  • Sooty mold

    Black, papery film on leaves and fruit that wipes off; it grows on honeydew.

    What to do: Control the insects making honeydew; the mold then weathers away.

  • Spider mites

    Fine pale speckling on leaves, dusty undersides and fine webbing; leaves bronze and drop.

    What to do: Hose the undersides of leaves.

Growing sweet potatoes? Let Gardyn keep track.

Gardyn tells you when your sweet potato needs water based on your local weather, reminds you to feed and prune in season, and keeps every harvest and photo.

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General guidance, not medical or veterinary advice. Poison Control (US): 1-800-222-1222. ASPCA Animal Poison Control: (888) 426-4435.