New Zealand - sub-tropical zone

Growing Sweet Potato/Kumara

(Ipomoea batatas)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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(Best months for planting Sweet Potato/Kumara in New Zealand - sub-tropical regions)


  • Harvest in 105-120 days
  • Shoots or cuttings (Slips). Sow seed at a depth approximately three times the diameter of the seed.
  • Best planted at soil temperatures between 17°C and 35°C.
  • Space plants: 40-60cm

Frost tender 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’ll 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/Kumara

Use mashed, boiled, roasted, baked or fried. Or use in soups, pies, casseroles, curries and salads.

Your comments and tips

23 Sep 14 Paul (New Zealand - cool/mountain climate)
Is it possible to grow kumara on the westcoast south island?
31 Oct 14 Maihi shortland (New Zealand - sub-tropical climate)
I live Perth do you no where I can get Kumara seeds from thanks
05 Nov 14 Anne (New Zealand - temperate climate)
Tips for Hamish. Buy some kumera (sweet potato in Melbourne, although I think you can only buy the yellow ones. Put in a glass jar which is big enough to just hold it in the neck of the jar without completely submerging it. Fill jar with water up to the top of the bottom third of the kumera. It will start sprouting in about 14 days and you can, then, pull off the sprouts and plant them out. Good luck.
17 Nov 14 Alfredo P Hernandez (New Zealand - sub-tropical climate)
I live just outside Port Moresby, PNG and our compound sits on a landfill, as this is a newly-developed subdivision for expats. There's no original top soil around our compound because of this landfill, so we try to make do with the kind of soil we got here to grow veggies - pak choy, cukes, sweet potato, bitter melon, snake beans, chinese cabbage, and all those that we could use from Yates. our first problem is germinating the seeds as we don't have the right type of soil available, that's why most of our seedlings look stunted, or the roots have not developed as they should... they couldnt even fill up the 1.5 inch seed pots that i use to grow them. i am trying to develop compost from grass removed from our backyard, which serves as our food garden, so we could have something to grow our veggies with in future... any comment on black soil from landfills we have here, which we thought could grow our veggies... thanks for any ideas.
31 Jan 15 Amy (New Zealand - sub-tropical climate)
Hi to get any variety of Kumar you should go to the farmers markets, scope out any moari potatoes and kumra, eat one see if you like it, if so simply place a few older runnier ones in a cardboard box and place in garage, when theres no chance of frost, simply cut into quarters be carful of shoots and simply plant, I like wine barrels, start with old leaves, then maybe old twigs and peat moss if you have it, I use coconut liners too, plant 3-5 in a circle only filling barrel 1/4th, when we'll established plant another 3-5, cover with potting mix and seaweed or sheep pellets, about 1 litter, then repeat till you have around 1-2 bags potting mix, 2-3 whole Kumar and potatoes cut x4= 12-16 Kumar/ potatoe plants, 2-6 litters sheep pellets or seaweed, and about 3-6 litters coconut liners old leaves twigs to cover bottom, in 3 months the barrel will be filled with 10-30 and you can pick when you eat, no waste, remember to save a few and repeat . No cost of buying anything than your first meal, and you enjoy 10-20 meals as a result of plsnting already sprouted plants!! Plant 1 barrel of spuds 1 kumara , I musclin and rocket mix in a few spring onions from the ends of your old ones, and through in a few parcell, you will not be disappointed I promise!
01 Mar 15 Bruce Gare (New Zealand - cool/mountain climate)
can anybody tell me if you can grow kumara in Canterbury South island
10 Mar 15 Olmec Sinclair (New Zealand - temperate climate)
Bruce, I know kumara were grown in Kaikoura by Maori (no tech.) and my mother-in-law has attempted some there this season.... the plants look good. Might depend on where you are, what tricks you can employ to make it work. Maori had some techniques for raising soil temperatures like adding charcoal to make soil darker, absorb more solar. I am interested in trying here in north canterbury
06 Apr 15 Lorna Warrington (New Zealand - sub-tropical climate)
We have a barrel compost bin and threw a kumara in it with the potato peelings. The Kumara has grown but we don't know when to pull it up. The foliage is still growing quite well and shows no sign of stopping. When do we pull it up to see if we have any produce please?
23 Apr 15 Maxine Stewart (New Zealand - sub-tropical climate)
There is a type of kumara called "Rubicon" which I would love to source if that's possible. It's dark purple, both the skin and the flesh, and has a rich and delicious flavour. Does anyone know of it please?
02 May 15 Toni Paton (New Zealand - temperate climate)
I have just harvested my first crop of kumara {in Hamilton} and have found that I have lifted them a little early. I did some research and they are much like potatoes in that the foliage either dies off or turns yellow when they are ready. While we got some decent sized ones there were a lot of small ones. I suggest leave them as long as possible. We got some seedlings started from peelings that sprouted in the compost, and from some that had grown on the tuber we bought from the supermarket, so once you buy a kumara you have the potential to grow them. I lived in the Gold Coast and tried growing them in a bucket with potting mix. They were growing fine but I returned to NZ and have no idea how they turned out.

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