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

Your comments and tips

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25 Mar 18, Julie Casidy (New Zealand - temperate climate)
When should I dig up Kumara? I didn't get them into the ground until late in spring. Should I do so before the first frost? I live in Wellington and never grown them. Yours thankfully Julie
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30 Mar 18, Prakash Chandra (New Zealand - sub-tropical climate)
You can dig out Kumasi when you see the end of vines and the leaves are turning yellow or just take a hand fork and dig around one plant carefully and see but do not dig the plant outright
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21 Mar 18, Kathy charles (Australia - temperate climate)
I planted 3 tubers of yellow and 1 purple sweet potato in October 2017 now March have picked first purple one but cannot find even a little yellow tuber. Healthy looking plants but WHY no s/potato. Thank you in advance
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23 Mar 18, Mike (Australia - sub-tropical climate)
Cut off some runners/vine and plant them - better than tubers. About 18
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10 Mar 18, Greg (Australia - sub-tropical climate)
I'm in Ipswich , SE QLD. I planted five purple sweet potato slips back at the beginning of August (2017). They have been in the ground seven months. They have grown well but have not flowered or died back at all, unlike the normal orange ones i grew the previous year. I've had a little bit of a dig around but have not found any tubers at all. Has anyone grown these before in my climate and should i be expecting to find tubers by now? Perhaps they went in at the wrong time of year? If i could upload a photo here, i would. Thanks for your help!
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11 Mar 18, Mike (Australia - sub-tropical climate)
I planted the orange ones one summer and they produced heaps. The next year nearly nothing. I talked to a farmer a few months ago and they plant slips. That is they go onto an existing growing crop about 6-8 weeks old and they take slips/runners/vine
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13 Mar 18, Mike (Australia - sub-tropical climate)
They cut this off from my post. You need a slip about 18
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04 Mar 18, Sue Ussher (New Zealand - cool/mountain climate)
I live in Fairlie South Canterbury and want to know if I could grow Kumara here and what month should I be planting them
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25 Feb 18, Chloe (New Zealand - sub-tropical climate)
I have two furiously shooting kumara that have been growing in the pantry (!) Whilst I was overseas. I'm located in a very sunny spot in Auckland, is there any point in attempting to grow them now? (End Feb)
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27 Feb 18, Mike (Australia - sub-tropical climate)
Give it a go.
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Showing 131 - 140 of 316 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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