The sweet potato, or kumara was grown in the milder districts of New Zealand by Maori from very early times. Traces of their kumara gardens and storage pits can be seen in many parts of the country. The kumara is not a close relative of the potato, the chief resemblance between the two is that they both produce edible underground tubers.

Varieties of sweet potato are grown throughout the tropical world, originating in South America. The sweet potato, Pomona batatis, is frost tender and should not be planted until all dangers of frost have passed. Kumaras do best in a sandy, well-drained soil in a warm sunny, sheltered position. Humus dug into the soil will improve the crop, but it needs to be well rotted and mature: fresh manure and too much fertiliser will cause the plants to make too much top growth in expense of the tubers. The plants are usually bought from nursery men as rooted stem cuttings known as slips. These plants originate from last year's tubers. They are planted about 60cm spacings in rows about a metre apart. Like potatoes, the young plants are earthed up at frequent intervals. The stems with their bright green arrow shaped leaves spread out in all directions and root down into the soil at the nodes. This needs to be discouraged by lifting the runners and shakin the soil off them or cutting the roots off by cultivating underneath the runners with a sharp hoe which also has the benefit of getting rid of any competing weeds.

Kumaras, unlike potato, are not troubled by blight and are pretty pest free. The hawk moth caterpillars, native to New Zealand fed on the leaves of the Maori kumara plantations. Like potatoes, the kumara plants should not be allowed to dry out if a good crop of tubers is expected. The plants need a long growing season and the tubers need to be lifted as they will be damaged by leaving them in the ground during cold winter weather.

The tubers are usually of an elongated shape, but sometimes more spherical, with the colour of the outer skin whitish, yellowish or shades of purple in some varieties. Kumara need to be well dried in a cool airy place which hardens the otherwise tender thin skin. Kumaras freeze very well; all you need to do is clean them and cut them into suitable sized pieces for roasting, free-flow freeze them and store in a large plastic bag in the freezer.

The nutritional value in kumaras is chiefly starch with a small amount of protein, and some sugar which gives the tubers their slightly sweet taste. They can be boiled and served in pieces, mashed or roasted.

sourced from Fairfax Media. 18 September 2008