New Zealand - sub-tropical zone

Growing Sweet Potato/Kumara

(Ipomoea batatas)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
                P P P  

(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

28 Nov 15 George Washington-Raleigh (New Zealand - sub-tropical climate)
When growing kumara from slips, it is not even necessary that they have grown roots before planting them - just keep the soil evenly moist for the first few days after planting, and in that time they will have grown plenty of roots. Commercial growers of kumara up here in Northland use this method always, as it ensures more that diseases are less likely to transmit from parent tuber to the slips, through the slips' roots.
20 Dec 15 Tristan Melling (New Zealand - sub-tropical climate)
Anna Holmberg, if the tubers are eaten straight away, the sugars have not had time to develop. They need to be left a couple of weeks or so before eating for best flavour
02 Jan 16 jenny (New Zealand - sub-tropical climate)
is it too late to plant kumera north auckland and best planting method and care please
26 Jan 16 Graeme Hawley (New Zealand - temperate climate)
I have a kumera with shoots.Is it too late to plant out? I live in Levin
01 Feb 16 Clarkee (New Zealand - sub-tropical climate)
What is the latest you have planted Kumara shoots and been successful? Mine keep sprouting in the cupboard and i'd love to give them a go if there is a chance of success :-)
15 Feb 16 Mj (New Zealand - sub-tropical climate)
is there a english name for the Kumara? I live in Australia and want to grow our kumara from back home but no one here knows what kumara is except that its a sweet potato. any help will help Ta
05 Aug 16 Beau (New Zealand - sub-tropical climate)
How do I grow kumara in black sand. Location Kawhia. Cheers
08 Oct 16 Kathryn (New Zealand - temperate climate)
Hi I live in Canterbury. My Grandfather used to grow purple Kumara near Staveley and they did well (no hothouse). I am wondering if I could grow orange kumara in a raised garden here in Christchurch please?
23 Nov 16 Gabi (New Zealand - sub-tropical climate)
I have been planting out my shoots, mounds of sand and compost etc, only to find something is taking them, even those covered by bird netting and cut out milk bottle (like a fence around the plant). Even those established ones from 2 weeks ago are now gone, over night, soil is quite disturbed. Any ideas? Its not rats, the trap beside the plot is empty.
29 Nov 16 Brian Harding (New Zealand - sub-tropical climate)
I have grown many kumara, and find that if the soil is light ie, peat, sandy/ loam, the best varieties to grow there are Toka-Toka gold (white/gold Kumara) or beauregard (orange), if you have heavier clay like soil, alluvial, the Red kumara can also be grown there, I calculate a period of 126 frost free days to grow kumara, if you can cover your plants, it is better to do that at the planting end of the season, rather then the harvest end . Make sure your soil is dry when you plant the slips(cut slip 25 mm above ground level from parent root) after planting (asap) water, they only require approximately 400 ml water, then another watering in the evening of about 300-400 ml if it is a warm day . In northland you can plant into the first week or two of January . Happy planting .

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