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

02 Jan 14 GEORGE (New Zealand - temperate climate)
I've recently(Dec 2013 ) planted kumara shoots in greenhouse located at MOSGIEL as experiment.,look forward to see what happens
05 Jan 14 (New Zealand - sub-tropical climate)
Hi, I was given some slips a week ago and I'm unclear, do I hump them and build up the soil like growing potatoes? Thanks
12 Jan 14 kendyl (New Zealand - sub-tropical climate)
I have started growing sweet potato slips from a cutting of sweet potato. I will see if any potatoes grow from the cutting as well as plant the slips and see the difference in growth. Check out my video for more info on how to grow your slips.https://www.youtube.com/watch?v=jAn9jpAkTlw
26 Mar 14 growgoodnz (New Zealand - sub-tropical climate)
Kumara - I am growing kumara in a hot house in Wellington. Can anyone tell me if i should pinch off the growing tips? They are up to a metre long.
06 Apr 14 steve (New Zealand - temperate climate)
Just harvested my first kumara in my port hills garden. it is a good size and look forward to trying it tomorrow for tea. next year I will try again and give them more care, they didn't get enough water but still seemed OK.
26 Apr 14 Evelyn (New Zealand - sub-tropical climate)
I now live in Queensland Aust, and thankfully Kumera is available here.It grows well in our sandy soil, with good rich compost added, then mulched. Just buy the vegetable and cut an end piece off (with buds starting) and place in soil, they're away!! So easy and delicious. try making stuffing for roasted chicken with them! Yumm!
04 May 14 Diane (New Zealand - temperate climate)
What causes the kumara to have holes in when they are harvested and how can this be stopped
25 May 14 Nand (New Zealand - sub-tropical climate)
I planted a row of kumara last spring on a trial and harvested them this weekend.The harvest was very good and big sizes. The problem was some of them were infested and had borer holes,but no insect inside. can some on advise me please what to so I can improve this next season.
26 May 14 Holey Kumara Tips (New Zealand - sub-tropical climate)
Tips for Diane and Nand: If borer are the cause of the holes, take a look around your garden. Are there any old borer infested weather boards or posts nearby? If so, remove those because when the borer hatch from them (they generally emerge in spring or when the weather begins to warm and are in flight season until late autumn) they'll be off in search of new woody habitats for their young (such as perhaps the cool damp underground tubers of your kumara). Review your kumara planting location too. If your plot was near a cooler area of the garden, try planting in a sunnier warmer north facing position instead. Make sure your kumara plot is well drained. Borer like damp places. Their holes can be found in the south facing weather boards of New Zealand houses because the south sides of buildings are cooler and damper. However they will inhabit the untreated interior timbers of buildings as well. Growing kumara varieties that are quicker to develop might help. Optimise growing conditions so crops grow faster. Borer would have less time to make a home before harvest in quickly maturing tubers. Try growing "clean" kumara plants from a supplier such as Koanga (www.koanga.org.nz). Read Gail Aiken's short "Kumara Growing" article on the Koanga website. Plant "tupu" or "slips". Avoid planting whole tubers, as these could be infested. Especially avoid planting tubers from a previous problem crop. You could try talking to staff at a local garden shop, find out if they can recommend any insect treatments for vegetable gardens. Borer insecticides for furniture and buildings are very poisonous, so never use them in or near a vegetable garden (or on anything you're going to eat). Apparently macrocarpa has some resistance to borer, so if you like using untreated wooden posts or fences (or sawdust) in or near the vege garden then try using macrocarpa instead of the woods preferred by borer. Other insects could be the cause of the problem. Look for worms or grubs in the infested tubers and try to identify what sort of insect grub it is, and what environment it likes. Then reduce the conditions that the pest likes and increase the growing conditions kumara prefer. When optimising growing conditions, assess the micro-climate, soil (drainage, ph, soil content, nutrients etc), as well as nearby host plants and other small animal populations that might be connected to the pest's life-cycle or preferred habitat.
27 Jul 14 Hamish (New Zealand - sub-tropical climate)
I live in Melbourne and would dearly like to grow some real NZ kumara. Does anyone know where to get some? Thanks

Post a comment or tip about Sweet Potato/Kumara


Where are you?



All comments are reviewed before displaying on the site, so your posting may not appear immediately

See planting calendar for these climate zones

New Zealand - sub-tropical  

Home | Vegetables and herbs to plant | Climate zones | About GardenGrow | Contact us

This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. GardenGrow is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department. The information on this site is presented in good faith, but we take no responsibility as to the accuracy of the information provided.

Site design and development by Hutchinson Software