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 USA - Zone 5a regions

  • Plant shoots or cuttings (Slips). Best planted at soil temperatures between 17°C and 35°C. (Show °F/in)
  • Space plants: 40 - 60 cm 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 I leave them in till the weather of leaves change. ( Auckland grower)
07 Apr 24, Marc (New Zealand - temperate climate)
leave Kumara in the ground at least until mid April. Leaves start to die off or in Auckland slow down in growth. Make sure the edges of the bed are well mulched, this will keep the moisture in the ground and the top soil cool (cooler). I harvest the orange (Beaumont) ones first, followed by the red, then purple and gold as last. there is about a week between harvests. Allow the kumara to dry before storage other wise they will rot. Keep them well protected from rats, my first red kumara harvest was approx 20kg until the rats consumed them in 4 nights to 2 kg.
29 Mar 24, Celeste Archer (Canada - Zone 7b Mild Temperate climate)
Harvest once about HALF of the leaves start to fall over and die off (turn yellow) -- HOWEVER I'm not sure if you planted at the being of October or the end. Given good growing conditions it should take about 120 days -- if you planted at the end October then that is about 120 days.... but it could take longer -- and since the leaves have not fallen over, then I would say, it will take more time. If you planted at the beginning of October, then you are taking a lot of days -- and it could be that the growing conditions have not been optimal for the whole time.... and I would still wait for leaves to fall over... but I would start to wonder if perhaps for some reason all the conditions that your plant needs to have met in order to set tubers have not been met (nutrition, soil type/ph, water, sun light, temperatures etc.). Same rule for potatoes, harvest once the leaves started falling over and turning yellow. That is to say: as long as the leaves are a upright and green they are still collecting light and storing energy (making tubers - and making them larger)
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
28 Nov 23, Theresa Tyree (USA - Zone 8a climate)
I am an eight a and now they are calling at 8B. I’ve grown sweet potatoes, very successfully in the ground the past two years, Your greenhouse if it is heat controlled should grow them very well but maybe not in December January February because they like the heat check out traditions on YouTube they did it. But I think they fertilized too much. Lots of leaves no tubers. Good luck.
30 Nov 23, (USA - Zone 3a climate)
Too much leaf is too much nitrogen.
15 Oct 23, Angi (Canada - Zone 8a Mild Temperate climate)
Has anyone successfully grown sweet potaotes year round in a greenhouse? This year I did an experiment with one slip from an organic sweet potato, it grew, and grew in a pot and now i have tubers! I would like to try and grow these year round with lights and heat?
10 Aug 23, Frankie (USA - Zone 9b climate)
Trying to grow in my apartment.. any advice welcomed.. what kind of soil should I buy? How often should I water? I don’t get direct sunlight how long should I leave outside on my patio?
01 Jul 23, Peter (USA - Zone 10a climate)
Can you just plant a sweet potato in the ground and sprout a vine?
Showing 1 - 10 of 306 comments

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