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Sweet potato, a crop that grows well in cool climates

Sweet potato

From the tropics, sweet potato thrives in temperate climates when they get enough water and warmth.

Key sweet potato facts:

Name: Ipomoea batatas
Family: Convolvulaceae
Type: annual tuber plant

Height: 8 inches (roughly 20 cm)
Exposure: sun
Soil: rich, light, and well-draining

Bloom: from July to September  –  Harvest: September and October.

This plant, part of the Convolvulaceae family (just like bindweed), grows low to the ground, boasts densely packed, occasionally colorful leaves, and flowers that remind us of other ipomoea species.

Discover how to cultivate this veggie with sprawling stems; you can harvest its tubers in September and October.

Planting Sweet Potato

A perennial in tropical areas, from which it originates, the sweet potato grows as an annual in our latitudes.

You don’t sow sweet potato; you plant it like regular potato, straight from another tuber.

Where to plant it?

Sweet potato thrives in deep, humus-rich soil that’s permeable, well-draining, and on the light side.

How to plant sweet potatoIt absolutely needs full sunlight and a temperature of at least 68 to 77°F (20 to 25 °C) to grow its tubers. Hence, planting in open ground is meant for warm summer regions.

Elsewhere, container growing or greenhouse planting still works great. Anyhow, with seasons turning warmer as time passes, we might just get to grow sweet potato in places further and further north (or south, in the Southern hemisphere).

When to plant?

In mild climates, sweet potato tubers are planted in open ground in April or May. Temperature must hit that sweet spot of 68°F (20 °C). Tubers germinate from mid-February to mid-March.

How to plant?

It’s already possible to buy sweet potatoes seedlings in pots or mini-clumps from garden stores, and transplant them to the open ground from May.

For those with a green thumb craving more control over germination: get your hands on tubers or even tuber fragments with at least one eye:

  • Fill pots (at least 12 inches in diameter, or 30 cm) three-quarters full with soil mix. Or use seed trays or a mini-greenhouse.
  • Plant whole tubers (or fragments) atop the soil horizontally, embedding just a third in the substrate.
  • Keep the substrate moist and place the pots in a very bright room with temperatures of at least 68°F (20 °C), with 77°F (25 °C) being ideal.

After about two weeks, the seedlings should be around four inches tall. That’s when to transplant them to open ground or a greenhouse. Whether in open soil or in a greenhouse:

  • Work the soil deep to fluff it up nicely.
  • Add compost for enrichment.
  • Draw furrows, spaced 32 inches apart (80 cm) and 6 to 8 inches (15 to 20 cm) deep.
  • Position the seedlings, allowing for 12 inches (30 cm) space between them.
  • Fill with soil and press down gently.
  • Water abundantly.

Sweet potato care

Diseases and pests on sweet potato

It’s rare to find pests on sweet potato, but the occasional caterpillar worms its way around at times.

  • Water regularly, keep that soil cool at all times in summer! Lessen the watering a tad before harvest time. Got a drip irrigation system? Sweet potato loves it!
  • Weed and till right after planting. Once started, you won’t have weeds growing anymore.
  • Hill up soil around the plants once they show some growth spurts. Tubers will form on buried stems.
  • Mulch it up! Abundantly, of course. Treat your soil well; it deserves cover too, at least until the sweet potato leaves block out the sun.

Sweet potato care

Sweet potato harvest

Harvest season kicks off in September or October. Leaves turning a soft yellow hue is your cue. If it doesn’t freeze yet, keep them in the ground until November.

How to harvest sweet potato and when Got a garden fork? Use it to uproot those tubers (a spading fork is great, too). Let them bask in the sun for a day for them to cure, but not for too long, and bring them in if it rains so they don’t get wet.

Wait a fortnight before munching, turning starch into sugars takes time. Store them in a cool, dry place away from frost. They’ve got a pretty long shelf life which you can greatly extend by keeping them in a veggie silo, not as long as regular potato, but they’re worth every bite!

Sweet potato in cooking

Cooking a sweet potato? It’s pretty much like prepping regular spuds. Thanks to its hint of sweetness, it is also delicious in desserts too. Sweet potato isn’t just about taste; it’s full of potassium, vitamin A, and antioxidants.

Images: 123RF: Sergiy Akhundov, Piyaset Sutthiwanjampa; Pixabay: George, Isa, Chang Min Shin

Written by Pascale Bigay | Writing is woven into Pascale's life, the threads of which also include nature, botany, gardening... That's why her words share such an immersive experience, a fascination with the simple discoveries of garden life, wonderful ornamental plants, tasty veggie-patch fresh recipes and the occasional squabble with her chickens...
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