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 09, Starrlite (New Zealand - temperate climate)
Hi there :-) found this thread while looking for a diagram of kumara (sweet potato) and thought this info might help you Jason. In early Feb, had this awesome fella come show us how to plant kumara in the traditional way, used successfully by Maori before European colonisation. I recently emailed him asking for general care and cultivation tips... this was his reply: "Kia ora ano sis, chur mean, glad to hear the kumara are in abundance! Have y'all pulled the runners up yet? - about 3 weeks ago you shouldve pulled up the runners on a sunny day and exposed the roots to the sun for a few hours to kill them. Otherwise the plants direct energy away from the tubers and into setting down new roots via the runners and your kumara wont be as big as they could. If you havent done it yet, still do! At that point you can also start harvesting the new shoots of vine growth - pick leaves and vines that are still that brighter green and use it like puha or watercress. If you eat mature leaves it might upset your stomach so kia tupato! (you probably already know all this!). This has same effect of directing energy to the tubers." For your reference, "puha and watercress" are greens that can be added to salads or boiled/blanched similar to spinach and silverbeet and "kia tupato" means I need to "be careful" - eating mature leaves can be harmful! Well, I am off to pull up the runners and expose them to the sun! Glad there is some today :-) Good luck with the kumara growing!! "As the garden grows so does the gardener." - Proverb
11 Feb 10, Liz (New Zealand - temperate climate)
Sandra, have a look at this site
17 May 12, Aaron (New Zealand - temperate climate)
hi what is the best way to store kumara thanks
08 Jun 15, Winsom (Australia - sub-tropical climate)
Hello, saw where you have the purple sweet potato cuttings and would post to someone who was looking for it. I live in Brisbane and was looking for the purple skinned sweet potato. How do I go about sending you the costs for this? regards Winsom
09 Mar 17, Lhatso (New Zealand - sub-tropical climate)
Hi do you know where I could buy the purple sweet potato that is purple flesh in side the skin as well.This variety is Grown in Japan
09 Mar 17, John (Australia - temperate climate)
Log onto - for a list of varieties. If you contact them they should be able to help you. Sweet potato is very easy to grow from cuttings. Just put cuttings into a jar of water and they will soon grow roots, then plant them. All the best.
16 Mar 17, Sandy.G (New Zealand - temperate climate)
Hi there, I bought a bag of mixed kumara & in it was 5 varieties & 1 was a purple fleshed purple kumara. I think its maybe a relative of potato.. as I am allergic to nightshade family & on eating 1 of these set my tongue and throat tingling, spat it oit and rinsed my mouth out.. any ideas!?
17 Mar 17, Ken (Australia - temperate climate)
Potato is a member of the Solanum (nightshade) family while kumara (sweet potato) is a member of the Ipomoea family which includes other plants such as Morning Glory, a totally different Genus.The purple 'kumara' may have been a knobbly potato packed with the others by mistake.
19 Mar 17, Sandy Greer (New Zealand - temperate climate)
Thanks for that, but I also remember some Maori potatoes being very similar also to the look of this type I ex use to grow a lot of heirloom veges and it looked similar to what hr grew back then... Might buy 1 again and grow it to see how it a vine or an up right plant.
02 May 17, Pou TeRongomau (New Zealand - temperate climate)
October and November best time to grow kumara in the Waikato Hamilton area.
Showing 1 - 10 of 50 comments

Here is how they grow them commercially in sub tropical southern Queensland Australia. They hill the soil up with a 2' base and about 1' high - paddock looks like corrugated iron - wave pattern. They then take cuttings (called slips about 50-60cm long) of vine from a pre-existing growing plant. These are planted (in the top part of the mound) horizontally into the soil with just the tip sticking out of the soil. Keep well watered the first week or two until the plant starts growing. Good rich soil to start with and then do not fert again especially with N. You want root development not vine production. If looking for cuttings/slips/tubers ask friends/neighbours/produce companies/internet sites etc or start a tuber as stated here.

- Mike

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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.
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