Growing Sweet Potato, also Kumara

Ipomoea batatas : Convolvulaceae / the morning glory family

Jan F M A M J J A S O N Dec

Not recommended for growing in USA - Zone 5a regions

  • Plant shoots or cuttings (Slips). Best planted at soil temperatures between 63°F and 95°F. (Show °C/cm)
  • Space plants: 16 - 24 inches apart
  • Harvest in 15-17 weeks.
  • Compatible with (can grow beside): Best in Separate bed
  • New shoots on Kumara
  • Well grown Kumara

Sweet Potatoes require a long warm growing season. Plant in free draining loose soil. Fertilise before planting but no more when the plants are growing as it will encourage vine growth. They will go for miles and you will get no tubers. If they do start spreading, lift the vines off the ground to prevent them rooting.

Mound up the soil about 20 cm (8 in) before planting. Let the plants die down, (leaves die or turn yellow) before harvesting the tubers. Dry them in the sun for a few days. then store in a cool dry place for up to five months.

Culinary hints - cooking and eating Sweet Potato

Use mashed, boiled, roasted, baked or fried. Or use in soups, pies, casseroles, curries and salads.

Your comments and tips

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28 Nov 23, Theresa Tyree (USA - Zone 8a climate)
I am an eight a and now they are calling at 8B. I’ve grown sweet potatoes, very successfully in the ground the past two years, Your greenhouse if it is heat controlled should grow them very well but maybe not in December January February because they like the heat check out traditions on YouTube they did it. But I think they fertilized too much. Lots of leaves no tubers. Good luck.
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30 Nov 23, (USA - Zone 3a climate)
Too much leaf is too much nitrogen.
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15 Oct 23, Angi (Canada - Zone 8a Mild Temperate climate)
Has anyone successfully grown sweet potaotes year round in a greenhouse? This year I did an experiment with one slip from an organic sweet potato, it grew, and grew in a pot and now i have tubers! I would like to try and grow these year round with lights and heat?
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10 Aug 23, Frankie (USA - Zone 9b climate)
Trying to grow in my apartment.. any advice welcomed.. what kind of soil should I buy? How often should I water? I don’t get direct sunlight how long should I leave outside on my patio?
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01 Jul 23, Peter (USA - Zone 10a climate)
Can you just plant a sweet potato in the ground and sprout a vine?
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28 Oct 24, Geri (USA - Zone 10a climate)
No. Start sweet potatoes in a jar with water. They will sprout. Pick the rooted sprouts off and that is what you plant.
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04 Jul 23, (USA - Zone 4b climate)
A slip is a piece of vine about 400-500mm long. Dig a trench 50-70mm deep. Lay the slip in the trench and cover the slip over with soil. Leave the growing tip sticking out of the soil. Strip most of the leaves off the slip - not the growing tip part. Water well for the first week or two.
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02 Jul 23, (USA - Zone 10a climate)
Sweet potatoes are not planted as whole tubers like regular potatoes. Instead, they are grown from sweet potato slips, which are sprouts taken from mature sweet potatoes. Just twist off the slips, root them in water, and then plant them to grow sweet potatoes
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20 May 23, Mireya (USA - Zone 7a climate)
What kind/type of sweet potato can I grow in Northern Virginia (zone 7A)?
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01 Jun 23, (USA - Zone 3b climate)
Probably any type.
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Showing 1 - 10 of 35 comments
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I talked to a commercial grower yesterday. Fertilise the ground before you plant. What fertiliser you use depends on how fertile your soil is. You would need a soil test to really find that out. But fertiliser with a reasonable amount of N, good P and high K. Mix this through the soil profile. If you cut off slips, make them about .4m long, strip off most of the leaves but leave the growing head part. Dig a furrow 50-75mm deep and place the slip in the furrow (place the slip level in the soil). Cover the slip over with soil but leave the growing bit sticking out of the soil. You could put the slips in a jar of water for a week or so to start the roots growing. Once you have planted the slip make sure it is watered for the next week, lIke each day. The soil around the slip has to be wet for the roots to shoot and grow. After a week or so you should notice the plant growing. The slip will produce sweet potatoes from where you stripped the leaves off giving a higher yield of crop. If the vines grow really long then I believe too high N, but I was told they need plenty of N. I was mainly asking about the placement of the slip but will ask more about the fertiliser next time.

- anon

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