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

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)
24 Feb 24, Gerry (New Zealand - temperate climate)
Hello can I grow sweet potatoes in Clyde Central Otago?
18 Mar 24, Lex (New Zealand - temperate climate)
We have grown them successfully in Balclutha 2021/22 2022/23. This years crop 2023/24 Was slow getting going but perked up in December. The tops havn't grown as much as the previous 2 years but we are hopeful of getting a worth while crop when we dig them up. I would say just have a go. Because we have a shorter season it is tempting to put them in early like 1/11 but we think it is better to wait until the ground has warmed up. cheers Lex
14 Jan 23, Anonymous (New Zealand - temperate climate)
Has anyone planted Kumara in a Vegepod?
23 Jan 23, Anonymous (Australia - sub-tropical climate)
Why would you - they need a lot of soil around them.
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?
Showing 1 - 10 of 58 comments

Ask around nurseries or produce/farming depots /supply companies or phone some of them.

- Mike

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