
How to grow kumara
Kūmara, or sweet potato, are a delicious kiwi favourite. Used in meals from roasts to salads, they’re healthy and easy to grow at home.
Kūmara, or sweet potato, are a delicious kiwi favourite. Used in meals from roasts to salads, they’re healthy and easy to grow at home.
Kūmara, or sweet potato, are a delicious kiwi favourite. Used in meals from roasts to salads, they’re healthy and easy to grow at home.
Kūmara is a root crop that grows underground in a similar way to potatoes. Most people are familiar with Red and Gold, which are the main commercial varieties, but there are a range of other colours from dark pink, orange, golden, pale pink, and white to choose from. All do well roasted, mashed, or in salads so just choose a variety that’s available in your area.
Here are the five main varieties:
Potato Type | Cropping | Uses | Maturity | Tuber Shape | Skin | Flesh | Flowers |
Huakaroro | Main crop | Buttery taste, waxy, great for boiling. Good keeper. | 120 days | Round oval | Cream | Cream with deep eyes | Many |
Karuparera | Main crop | Great for salads and boiling. | 120 days | Round | Deep purple skin with white eyes | Cream | Many |
Kowiniwini | Main crop | Waxy variety, ideal for boiling. | 120 days | Round | Multi-coloured | Cream | Many |
Moemoe | Main crop | Ideal for boiling and baking. | 120-130 days | Round oval | Light purple and cream | Cream | Many |
Waiporoporo | Main crop | Great boiled. Lovely tasting potato. | 110 days | Round oval | Multi-coloured | White | Many |
Kūmara are a frost-tender crop that prefer a warmer climate and need a hot summer, so they can be a challenge to grow in cooler areas of the country.
They need plenty of room to grow, as they produce a fair amount of vine-like green growth.
You can grow kūmara in two ways:
Kūmara need full sun and rich, fertile soil. They prefer a warmer climate, and can be a challenge to grow in the south. They don’t like frost, so protect them with frost cloth or plastic if there is a risk.
Plant in spring, to harvest in autumn. Kūmara need at least 3.5 months of growing time.
In this guide we’re planting two rows of kūmara. You can plant as many rows as you want, with your chosen variety.
Prepare the area well in advance of planting. If you are starting with an existing garden bed dig in organic matter like sheep pellets, and compost to your soil. Then add a layer veggie mix on top.
Kūmara grows like a vine and they will spread, so they do need a bit of space. If you want to keep them contained, plant them in a bed that’s prepped with a solid base about 40cm down. This will stop them from burying themselves too deeply, and will make harvesting easier.
Created a raised row to plant into, leaving hollows on either side.
Plant shoots 2/3rds into the ground, spreading the roots out on either side, to encourage them to travel horizontally.
Space them out with about 30cm between shoots.
Give them a good watering-in with a can of seaweed tonic, to help prevent transplant shock.
Add a layer of pea straw in the hollows on either side of your rows, to help keep the soil warm and moist.
As the vines grow, the stems will naturally try to spread and put down more roots when they touch the soil, so it’s important to lift the foliage regularly to stop this root growth. This will force the plant to put energy into tuber growth rather than leaf growth.
Water freshly-planted shoots often until they settle in, then only water when foliage wilts and during drought.
Protect new shoots from slugs and snails with slug and snail bait.
Kūmara are traditionally harvested after a full moon.
You’ll know your kūmara are ready to harvest when the leaves start to turn yellow, after about 3.5 months. Simply cut the foliage back, and gently lift the kūmara using a fork, being careful not to damage the tubers.
Leave them on the garden bed to cure in the sun for a few days, protecting them at night with newspaper or a sack.
After that they’re ready to enjoy, or will store well in a cool dry place.
TIP: Pick the best-looking tuber to propagate next year’s harvest. Wrap it in newspaper and store it in a box.