Kūmara is the Māori word for what is commonly known in other parts of the world as sweet potato. It was originally brought to New Zealand more than 1000 years ago by early Māori settlers, but the modern kūmara we eat today evolved from an American variety that was imported in the early 1850s.
How To Grow Kūmara (Sweet Potato)
Despite what its alternative name may suggest, kūmara is actually only distantly related to the common potato – in fact it is a member of the morning glory family. One of the best things about kūmara is there are so many varieties! Purple, orange and brown skin; purple, orange and golden flesh… all these varieties have different levels of sweetness, and the texture can be anything from smooth and waxy to fibrous and firm.
Kūmara is very easy to grow, and following just a few simple rules will help ensure a tasty and abundant crop. First of all, the soil must be friable, light and slightly acidic – a pH between 5.6 and 6.5 is ideal. It is also a good idea to contain the kūmara vine in its own bed or tub, as it can take up a lot of space and will dominate other plants.
Though kūmara is not fussy, the one thing it won’t tolerate is frost – so planting must occur after the last frost of the season. It loves the sun and will thrive at an average temperature of 24°C. The crop also likes a moist soil, however waterlogging the plants will lead to root rot and unwanted pests. To avoid this, the key is consistent irrigation, especially in the early days after planting, with a deeper soaking if the leaves are starting to wilt.
Commercially grown kūmara is sown in beds of well fertilised soil piled 30-40cm high over a layer of hard clay or plastic sheeting. This firm surface beneath the growing soil prevents the roots from digging down and will favour the growth of tubers just below the soil’s surface.
Kūmara has quite a long growing season, and it may need up to six months for the tubers to reach full maturity and flavour. Harvest before the first frost using a small trowel, so you can dig and loosen the soil around the tubers without incidentally piercing or bruising them. Leave the root system or any undeveloped tubers underground, and it will re-sprout next spring!
Pot Luck
If you don’t have a large garden, never fear – kūmara also grows extremely well in pots. Just plant it in a container about 50cm deep, place it in a sunny spot and water regularly, and you’ll be rewarded with plenty of tasty tubers.
Planting
Kūmara propagation is easy. Simply buy a small, organic kūmara from the grocer and place the tip in water. Leave it in a sunny spot and watch it grow roots and leaves, then transplant into the yard.
Pruning
Like most tubers, kūmara runners can get a little rampant if left unchecked, so just prune them off every so often. You can use the fresh leaves in salads and stir-fries as you would spinach.
Pests
Be on the lookout for weevils, as they will lay eggs in the stems and tubers. If you see weevils, you should act quickly – destroy the infected plants and spray the rest with a natural bug repellent.
Harvest
After harvesting, kūmara tubers should be left to dry in the sun for a few days. A dry and well-cured skin will help the tubers to last several months in a sack in a dark
and well-ventilated place.
Good things take time
It will take kūmara between 90 and 170 days to grow – and the longer you keep them in the ground, the more vitamins they’ll absorb and the bigger they’ll grow.
Know your Kūmara
Gold flesh
Soft and subtle, gold kūmara is extremely versatile. It’s perfect to mash, or you could add it to a creamy chicken curry.
Purple flesh
This is the least sweet variety, and requires a longer cooking time. The vibrant colour looks amazing in salads.
Orange flesh
A well-known variety, orange kūmara has a sweet flavour and firm texture. Toss wedges with oil and herbs and roast for tasty chips.
