Kumara: Sweet Potatoes - Ipomoea batatas
In most countries they are called sweet potatoes, but in New Zealand they are known by their Maori name kumara. Kumara are one of the most popular vegetables in New Zealand and one of the healthiest you can eat.
They are an excellent source of vitamins and minerals, are virtually fat-free, cholesterol-free and very low in sodium. Kumara have more fibre than oatmeal and provide many essential nutrients, including vitamin B6, calcium and iron.
Available in red, gold or orange, each variety has a deliciously different colour and taste. Red kumara has a creamy white flesh, firm texture and tastes delightfully mellow. Gold has a soft texture and is slightly sweeter. The orange variety is firm and tastes the sweetest.
When, where and how to plant:
Kumara is bests grown in warm climate with a long hot summer. In cool areas you will need to protect young plants from frost or try growing indoors.
In late winter early spring start by sprouting Kumara shoots. Use a polystyrene or plastic box with drainage holes and a clear plastic or glass lid. Line the bottom with 10cm of horse or pig manure that is just starting to rot. Cover that with a layer of straw and top it off with a few centimetres of sand. Push a couple of kumara tubers into the sand layer, then water and cover. Keep the seed bed well watered.
As the manure heats up, the kumara will sprout vigorously. Lift the lid to allow for air circulation to prevent mildew and fungal problems. The sprouts can be cut off the tuber when they’re about 5cm – 2 inch’s high and the roots can be easily separated from the loose sand. From a single tuber, it’s possible to get a dozen new plants. This will take approx 4-8 weeks.
Kumara require a long warm growing season. Plant in free draining loose soil with a hard pan about a foot under the surface. If you don’t have a clay pan under the soil bury some thing like corrugated iron a foot under the soil to act as a hard pan. If your soil is too heavy, the skins will be covered in a patchy brown virus. If there is no hard pan, and you have fertile soil, the tops will go for miles and you’ll get no kumara. Blend in a balanced fertilizer prior to planting, don’t be tempted to fertilise while plants are growing - you will encourage leaf growth as opposed to tuber growth.
Plant out plants as soon as the threats of frost has finished in the spring. Plant 10cm deep and 40cm apart, bend the roots of the cuttings under, into a J shape when planting so the roots face up to the top again under the ridge of soil – this will prevent the vines from spreading too far. As the vines grow, the stems will try to put down new roots where they touch the soil, you want to avoid this, so lift foliage regularly to encourage tuber growth and not leaf growth. Kumara can be grown in containers. Pots need to be at least 30 deep and will require plenty of water through the summer to ensure good sized tubers. Sweet potato is usually trouble-free in the home garden but don't plant it in the same spot twice.
Harvest once leaves start to die down or turn yellow in the autumn. Dig them up and leave them on top of the soil to dry for a few days before storing. In cold areas it’s a good idea to take cuttings in the autumn to grow on inside for next years plants.
How to use:
Use as a vegetable to accompany any meal mashed, boiled, roasted, baked or fried. Or use in pies, casseroles, curries and in salads.