BOTANICAL NAME: Helianthus tuberosus
COMMON NAMES: Sunchoke; topinambour
FAMILY: Asteraceae, the daisy family
PLANT DESCRIPTION
A hardy, tall, herbaceous perennial that grows up to 3 m high with a yellow flower like a sunflower. It will grow in any soil but prefers light, sandy soil of good fertility. It does best in temperate climates, to the point of becoming an 'edible weed' in some gardens. In warmer, more humid areas it can still be very productive but is unlikely to persist in the ground from year to year. It will need to be replanted from stored tubers. Tubers store well in the crisper part of the fridge in a plastic bag. In tropical zones it can be grown successfully year round by regular replanting but is best planted at the beginning of the wet season.
USES
Jerusalem artichokes produce a large numbers of edible tubers. They are especially good for diabetics as they contain no starch, the carbohydrate is in the form of inulin and laevulin, which are readily metabolised as the natural sugar, laevulose. Tubers should be scrubbed not peeled and can be boiled or baked, when very fresh they can be grated raw in salads. This plant is also a useful summer windbreak for the vegetable garden. It can be used for animal forage, the tops can be grazed down in autumn, before harvesting. As a fodder crop for pigs, they can root up the tubers themselves. The attractive flowers can be cut as a 'cut flower', removing the flowers is believed to increase the yield of tubers.
PLANTING DETAILS
Propagation is by tubers, any small piece left in the soil after harvest will probably shoot, so plant it where you want it to grow, as it can be hard to eradicate (in cooler areas). The recommended planting time is spring. To plant, cut the tuber into 2 or 3 sections, each one with an 'eye'; cover the tubers with soil to a depth of 10 cm. Plant in rows 70 cm apart, 25 cm between plants in full sun, mulch well. Jerusalem artichoke needs a good supply of potassium, this can be supplied with wood ash, avoid high nitrogen fertilisers or the tops will grow at the expense of the roots.
HARVEST
Tubers can be harvested 4 to 6 weeks after flowering. Even though the flowers are pretty, yields will be better if the flower buds are pinched off as they appear. In cooler areas with well-drained soils it is better to dig them only as you use them. In subtropical areas and poorly drained soils the tubers may rot if left in the ground once the tops die back, so it is better to dig the whole harvest at once. Tubers do not store well out of the ground. Take care to store them in slightly damp sawdust or sand in a dark place; or store them in a plastic perforated bag in the bottom of the fridge.
