Growing Sweet Potato, also Kumara

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 20cm (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

14 Mar 22, Malcolm (New Zealand - sub-tropical climate)
I have grown a large bed of kumara in a school garden. The entire bed is covered in healthy top growth. But I can't feel any tubers when I lift up a section of top growth. I'm interested in the comments on pulling up runners, although I may be too late now, in mid-March. Do I just hack away at the long vines, cutting them back to where they enter the soil. Or am I wasting my time, since we are about a month from harvest?
09 Apr 22, Will (New Zealand - cool/mountain climate)
No, you are not wasting your time growing them. Even if there are no tubers, the top leaves can be harvested. They are commonly harvested & eaten in the Philippines. Steam them. They commonly used them with raw tomatoes, in their summer.
15 Mar 22, Mike Logan (Australia - sub-tropical climate)
In sub tropical Australia where I live, they grow them in rows. The rows are hilled up about 1/2m high and the slips are planted in the top of the hill. A slip is the last 200-300mm of the vine when they are about 10 weeks old. Plant the slip with the top part out of the ground, Keep soil moist until they start to grow. Your problem is you probably have over fertilised with nitrogen. Go by the time to harvest guide here if you don't have a crop by say 4mths then you probably won't. The potatoes will be around where you planted the tube or runner not along the vines.
04 Dec 20, Brian (New Zealand - sub-tropical climate)
My first attempt of growing Kumara was in heavy duty cardboard box, with a rigid base to stop the runner escaping. 1.5 kg tuber was harvested from one slip, I was impressed. Second year was in an old bath in full sun, 5 slips, harvest revealed a lot of small tubers. 3 kg. This year, 2020, I will combine my efforts in cardboard boxes again and the another bath. Layers of cardboard in the bottom of bath with mixture of compost, vermicast, gritty sand, soil and pea straw to preserve the slips from being removed by Wekas and or Pukekos. Liqiud fertilizer will be added to the new beds before planting, Intend to harvest before May 2012.
21 Nov 20, Len Lind (New Zealand - temperate climate)
I would like to try growing kumera here on Stewart Island in a tunnelhouse. Is there anywhere I can buy sprouts, slips?
18 Nov 20, Aitaua (New Zealand - sub-tropical climate)
Hi.. Can these sweet potatoes useful for planting here in Samoa?
19 Nov 20, (New Zealand - temperate climate)
They should be.
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. .
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.
20 Feb 21, Jay (New Zealand - cool/mountain climate)
Hi could you provide time of year for this method thanks
Showing 1 - 10 of 53 comments

I ate kumara everyday when visiting NZ and loved it! Because it was less sweet than USA sweet potatoes. I am craving it and need to find out how and if I can get seeds and grow it in Virginia? Would love your help on this!

- Kim Davies

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