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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17 Nov 20, Henk Stengs (New Zealand - temperate climate)
I have experimented with kumara for several years in Greymouth with mixed success so last summer tried growing them in old car tyres. Their black colour absorbs heat thereby increasing soil temperature. Three sets of tyres were used, each stacked two high. These were placed inside our tunnel house on the surface in a sunny position and filled with soil, with one slip allowed to grow from each central position from late November. Harvesting took place in early April, producing a total yield of 9 kg, with about 60% of shop quality, my best result yet. When I harvested the tubers I saw that they were confined to centres of potential growth areas, with no root development at their circumferences inside the tyre rims. Therefore over half of the volume of soil in each pair of tyres was not utilised. This year I will plant 2 sllps per tyre pair, positioned diametrically opposite, with root ends inside the rims to see if this will give a better result. I am interested in hearing from anyone else who has tried growing kumara in tyres. .
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18 Nov 20, (New Zealand - temperate climate)
They grow sweet potato/kumara where I live (Qld Australia) by the thousands of acres. They hill the soil up into rows about .5m high with a base probably .7m wide. They take pieces of vine (called a slip) about .4m long, strip most of the leaves off. Keep the growing tip on it. They place the whole slip just under the soil horizontally with the growing tip sticking out of the soil. Where each set of leaves were on the slip, roots will grow and potatoes will form. Water each day for the first 2-3 weeks. Just a side issue, tires may not be the best thing to grow vegetables in. Rubber compound/chemicals could leach into the soil.
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20 Feb 21, Jay (New Zealand - cool/mountain climate)
Hi could you provide time of year for this method thanks
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23 Sep 20, Elizabeth Gower (USA - Zone 10b climate)
Where can I get Kumara in the USA? I live in Southern Ventura County, Southern California and would like to grow some.
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23 Sep 20, Liz (New Zealand - temperate climate)
You probably need to look for sweet potato
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13 Sep 20, Adrienne (New Zealand - cool/mountain climate)
Can you plant an whole kumera in a container and get a crop?
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14 Sep 20, Anonymous (Australia - cool/mountain climate)
Yes you can but you don't need a whole kumera, a piece of vine will do. A piece about 30-60cm long of the new vine growth. Place in a trench with the tip sticking out of the soil, water twice a day for the first 2-3 weeks.
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17 Sep 20, (Australia - sub-tropical climate)
Or depending on how big the spud is, cut it into several pieces and let them dry in the sun for a few days then plant them.
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31 Aug 20, ganaa (Canada - Zone 2b Sub-Arctic climate)
how can i plant in in the polar? (Gardenate ; Not recommended for growing in Canada - Zone 2b Sub-Arctic regions)
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10 Aug 20, Nicky Holmes (New Zealand - temperate climate)
Hi can you please tell me if Dunedin is the right temperature to grow Kumars outdoors or is it to cold? Thanks.
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Showing 61 - 70 of 316 comments
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Plant the tubers that you want to grow but in a separate bed. They will sprout lots of shoots which will also have roots near the base. When the shoots are 40 to 50 cm long put a fork under the tuber and gently lift it out. Separate the shoots and plant them in the bed you have prepared for them as indicated in the article above. Last year, before I knew this, I planted several tubers where I wanted them to grow but after learning the right method I dug up three and planted out about 50 slips. The slips can be left in water while you are waiting to plant them out and in a few days mine put out prolific roots where the base was under water. You can also start the sprouting inside, cutting the tops off tubers and putting the cut down in shallow water, then planting them out when they start to sprout. Roots will also start growing but later than the shoots. Look for the eyes in the tubers as they are where the shoots come from.

- Paul

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