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 New Zealand - cool/mountain 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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20 Feb 25, Phillip (Australia - arid climate)
When do you plant sweet potatoes or potatoes in the Tara Queensland region
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31 Jan 25, Kieron McPherson (Australia - tropical climate)
Hello there in 2023 I bought 2 sweet potato pots from bunnings and we planted in our avocado orchard and just let it run wild for a few months, when it came time to harvest I got 100kg of sweet potatoes my question is why do you say- They will go for miles and you will get no tubers. Was I just lucky or is there more to it than that?
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29 Dec 24, Gordon EDWARD Bradberry (Australia - sub-tropical climate)
where do we get seedlings from
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05 Jan 25, (Australia - sub-tropical climate)
Best to use a piece of the vine (slip) from a growing plant about 450mm long. Plant in a shallow trench under the soil with the growing tip out of the soil. Keep well watered.
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24 Nov 24, Maree (Australia - tropical climate)
Can you sprout sweet potato seedlings from shop bought sweet potatoes?
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02 Dec 24, (Australia - sub-tropical climate)
Yes
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18 Nov 24, Care (USA - Zone 8b climate)
How to make light and airy soil for planting sweet potatoes?
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01 Nov 24, Dot Wise (New Zealand - sub-tropical climate)
Just planted 100 kumara slips (tipu). Hope to harvest by Waitangi weekend.
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25 Mar 24, Peter (New Zealand - temperate climate)
Planted 10 kumera slips in October 2023.... Harvested 50% of them 5 in March 2024....massive green foliage but sadly 6small (very small) finger sized harvest kumera is the only result...starting to get cooler but leaves still dark green....do I leave them in till the weather of leaves change. ( Auckland grower)
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07 Apr 24, Marc (New Zealand - temperate climate)
leave Kumara in the ground at least until mid April. Leaves start to die off or in Auckland slow down in growth. Make sure the edges of the bed are well mulched, this will keep the moisture in the ground and the top soil cool (cooler). I harvest the orange (Beaumont) ones first, followed by the red, then purple and gold as last. there is about a week between harvests. Allow the kumara to dry before storage other wise they will rot. Keep them well protected from rats, my first red kumara harvest was approx 20kg until the rats consumed them in 4 nights to 2 kg.
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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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This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. GardenGrow is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department. The information on this site is presented in good faith, but we take no responsibility as to the accuracy of the information provided.
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