Pier 3 Condo

Synonyms are H. tuberosus var. fusiformis., Helianthus tuberosus L.

Common names are Jerusalem Artichoke, Sunroot (Eng.); Girasole, Topinambour (Fr.); Alcochofa de Jerusalem, Aguaturma (Sp.); Erd Topinambur, Erdartischocke (Ger.); Aardpeer, Topinambour (Neth.); Hatichuk, Hathipick (Ind.); Cotufa (Philipp.); Brahmokha (Bangl.); Kiku-imo (Jap.).

Cultivars are in India.

Native to North America and introduced into Europe in the early seventeenth century. This form of artichoke is now widely distributed throughout temperate and tropical regions.

Cultivated to a limited extent in the Caribbean, Malaysia, East and West Africa, mainly at high altitudes.

An annual or biennial herb. Roots: fibrous. Stems: condensed, round, rarely more than a few cm in length. Leaves: in dense rosettes, light or dark green; form very variable, being divided, curled or broad; mature leaves have a bitter taste. Flowers: pale blue, rarely seen in tropical areas; flowering stem up to 1 m in height. Seeds: with pappus.

Temperature is an important factor influencing growth, the leaves becoming fibrous in high temperature conditions although endive is, in general, more tolerant to high temperatures than lettuce. Altitude also has an important effect on growth; more satisfactory growth is obtained from plants grown at elevations over 500 m than from those grown in lowland conditions. Flowers are rarely formed in short days, particularly when combined with high temperatures.

Propagation is from seed which germinates in 4-5 days from sowing. May be sown in drills 25-30 cm apart and seedlings initially thinned to 8-10 cm, later to 20-25 cm apart in the row. Approximately 0.75 kg of seed is required per hectare to give a planting density of 200 000 plants/ha. Lettuce is more frequently sown in containers or a seed bed and transplanted when 4-6 weeks old. In some areas, a black polythene mulch is used to reduce water evaporation from the soil surface. Irrigation: This is required at frequent intervals, particularly at transplanting and until the seedlings are established. Dry conditions are likely to induce premature flowering. Nutrient requirements: A good response is obtained to a high soil organic content and to top dressings of nitrogenous fertilizers. Phosphatic fertilizers encourage the production of firm heads. Tipburn in heading types of lettuce appears to result from an imbalance in the soil/plant/water system which may also be linked with temperature variation and nitrogen status of the plant. Some cultivars are resistant to this disorder.

Plants normally mature within 70-85 days from transplanting, depending on factors such as soil fertility and irrigation efficiency. Yield: Yields in the region of 6-12 t/ha may be obtained. Seed production: Seed is rarely formed in the tropics, except at elevations above 1500 m. Most cultivars are almost completely self-pollinated. A 600 m isolation distance is sufficient unless hybrid seed is being produced, when 1000 m is more appropriate. The average seed yield is 200 kg/ha.

The leaves should be fresh and free of discoloration; the leaf colour varies with cultivar. No signs of tip burn should be present, particularly on the inner leaves and seed stalks should be absent. Open-topped polythene bags are used to prevent moisture loss and reduce damage; they also allow for wetting of the heads to retain turgidity. At temperatures of 0-3C, heads may remain in good condition for up to 14 days at a relative humidity of 90-95%; weight loss may be up to 15%.

Normally used in the raw state in salads but also as a cooked vegetable, particularly in Southeast Asia. Loose-headed forms have a higher vitamin A content than heading cultivars.