Zea mays var. saccharata
Family: Poaceae

With origins probably in Mexico or Central America, sweet corn was part of the staple diet of the Central and Southern American native peoples prior to the arrival of the Spanish. It was introduced to Europe by Christopher Columbus in the 17th century and quickly became popular there. Hugely popular in the United States, it is generally served in the UK and Europe simply boiled, or perhaps barbecued, with butter and freshly ground pepper. However, a good sweet corn and crab meat soup is hard to beat, and sweet corn fritters are quite delicious. Milled corn can be used in breads, cakes and pancakes.

Varieties

Zea mays var. saccharata is an erect, monoecious annual, widely grown in both tropical and temperate regions. At maturity, cobs are borne in the axils of the broad leaves. The male flower with the pollen is the tassel at the top of the cob, the kernels are the ovaries and the cob itself makes up the female flower.

Each kernel has a silk thread running to the outside of the cob, through which pollen grains move into the ovary to effect fertilization. Cob and kernels are protected by a green, leafy covering husk. Modern varieties have been bred for higher yields, increased sugar content, less starch, greater disease-resistance, and general hardiness. There are many cultivars available, including some that are classed as supersweet.

Cultivation

Sweet corn produces separate male and female flowers, and cobs will not form unless pollination takes place. Corn must be planted in blocks, rather than in rows, for the pollen to be carried by wind, as it will not travel for more than a short distance. In the garden, choose a block in full sun and ensure that the soil is well drained and reasonably rich. While corn plants tolerate wind, they will not grow in cold conditions.

Enrich soil before planting by digging in a handful of complete fertilizer with a high nitrogen content or poultry manure to each square metre (yard) block. An additional side dressing of nitrogenous fertilizer when the corn is 15-20 cm (6-8 in) high is also recommended.

Sow seed in spring, 5 cm (2 in) deep, direct into the prepared bed, spacing plants 30-45 cm (12-18 in) apart. By placing two seeds in each space, the weaker one can be removed when the seedlings are 10 cm (4 in) high. In frost-prone climates, cover the young plants with cloches for frost protection, or sow seeds in a heated greenhouse in late spring, singly in individual small pots, and plant out the young plants as soon as frosts are over.

Gently remove all weeds as they appear, and provide ample water. During maturation, the kernels reach a critical point called the 'milk stage' when the kernel is composed of around 70 per cent watery sap and reaches its optimum sugar con-tent.

The corn is ready for harvesting and eating if a milky sap spurts out when a kernel is pressed with the fingernail. If left longer on the plant, the moisture content of the kernels decreases, the starch content rises, and the grain becomes floury in texture. The main pest is corn earworm but gardeners generally tolerate this and simply cut off affected ends of cobs.

Climate

Zone 7, but grown as a summer crop in all climatic zones.