Gardening – Easy care kumara

By Andrew Steens

I started lifting my kumara crop earlier this month, just in time for winter roasts. I could leave it until frosts kill off the top growth, but the tubers are already huge, so no point in waiting. It’s another bumper crop, with half a dozen big fat tubers from the first bucket-sized area of soil. I love this crop – it gives so much return for relatively little effort.

Most work occurs at the beginning – getting sprouts ready and preparing the bed (although this season I was too busy to sprout my own but a quick garden centre trip sorted that out). Around July or August, place some stored tubers in a warm, moist environment. I use a plastic bag in the hot water cupboard. Tubers produce about 10 sprouts each within a month or two, which are hardened off (and greened up) in a brightly lit area and then cut off and planted out.

In early October, I dig a barrow load each of horse manure and rich compost into a 2sqm raised bed. Having raised beds or mounds is important, as even though kumara need a lot of water over summer. Waterlogged soil can result in the tubers rotting away. A sunny spot is also essential, as is good shelter from cold winds. About Labour weekend, or a little later if it’s a cold spring, I plant out at 8 to 10 shoots to the square metre, with a generous dressing of blood and bone, potash and dolomite.

Always water well in the first week to help roots establish, then weed thoroughly in the first few weeks. After this, a mulch of wood chips helps conserve water and reduce weed germination till the vines cover the soil and prevent further weed growth. The vines soon scramble over the edge of the bed, but it’s easy to hack them back with a hedge clipper to keep them from taking over the garden.

Other than watering and trimming, there’s basically nothing else to do until harvest. Once dug, I wash the soil off and leave the tubers to cure under shade in the greenhouse; a warm porch works just as well. Once the skin is firm and no milky sap comes out when cut, the tubers are mature and ready for storage.

Last year, I stored my kumara in the kitchen in an antique kauri potato bin we’d brought in the far north. Bad mistake, not only do kumara lose a lot of moisture during storage, they also rot easily if the temperature is too high. As a result, the kauri planks warped like wet cardboard and fungal growth quickly covered the inside. I wasn’t too popular after that!

If you haven’t got the luxury of an old-styled root cellar, then a good alternative is wrapping the tubers in newspaper and storing them in wooden bins in the coolest room in the house; for example a laundry on the southern wall. The ideal temperature is between 13 to 16°C, colder than 10°C for any length of time and the tubers develop hard woody cores and may rot. Kept like this, they can store for six months or more, ensuring lots of great winter roasts!