Step-by-step Guide to Growing Sweet corn corn
Sweet corn (Zea mays fam. Gramineae)
Sowing to harvesting time: 9-14 weeks
Size: plants grow to about 1.2-2.4 m (4-8’) or more; cobs are 15-20 cm (6-8”) long Yield: 2-6 ears (or cobs) per plant; two the maximum in cool temperate climates
The plump kernels of, one of the most delicious of garden vegetables, reach perfection only in favourable summers when there is plenty of hot, sunny weather. Once past the seedling stage, though, the cultivation requirements are few, and many new hybrid varieties have been developed to withstand the rigours of the short and unpredictable summers of temperate climates. Sweet corn is highly nutritious, and ‘corn on the cob’ is a favourite with children. Once you accept that this vegetable is more at the mercy of the weather than most other vegetables, it is well worth a try, and in good summers you will be amply rewarded for your efforts. By selecting one of the many early maturing varieties, and with the careful use of greenhouses and cloches, you can extend the growing season for as long as possible, and in a mild year, harvesting can begin in midsummer and extend to late autumn. There is a certain satisfaction to be from picking your own sweet corn, and it tastes far better when freshly picked from your own garden than when store-bought. There is a chemical reason for this: the kernels contain a high sugar content, which rapidly changes to starch once the cob is severed from the parent plant. Corn that has spent a fair amount of time in transit from farm to shop, or lying on the shop shelf, will taste stale and bland.
Botanically, sweet corn is a member of the grass family, and the kernels you eat are the seeds, which are formed into tight rows on cobs. Unlike all other vegetables, sweet corn does its growing in darkness, rather than daylight. In its original habitat, sub-tropical America, days and nights are of equal duration; the long hours of daylight and short nights in cool temperate summers make it difficult for the plant to grow quickly and produce its cobs before the weather turns cold in autumn. This is why early sowing under glass is so useful; by giving the plants a head start and planting them out when the weather is warm enough, they will be able to get the full benefit of summer warmth and the grains should ripen in good time. More than any other vegetable, growing corn is a race against the advent of cool autumn weather.
Although the corn you eat is usually pale yellow, almost cream-coloured, or sometimes deep yellow, there are other varieties, which are used for animal feeds or decorative plants, with red, purple, or nearly black kernels. The plant itself is very attractive, and is sometimes grown in flower beds as an ornamental feature.
Suitable site and
Sweet corn revels in sun, so an open, sunny site is best. Because it is a tall plant with a shallow root system, it is vulnerable to winds and should be given some. Remember that fully grown sweet corn can easily overshadow smaller plants, so consider its siting carefully.
Sweet corn will grow in almost any type of soil but prefers a light, sandy and reasonably fertile one. Ideally it should be grown on a site manured for a previous crop, as too much fresh manure will lead to luxurious foliage rather than good ears of corn. If the soil has not been manured for a previous crop, it is best to dig in. If you are dealing with a clay soil, do this as early in the winter as possible so that it is thoroughly absorbed. If, however, it is sandy, gravelly or generally well drained, it will be better done in late winter, as such soils ‘digest’ very rapidly. The ideal soil pH is 6.5 so correct excessive acidity or alkalinity at some time during the winter. A week or so before sowing or planting, work in a compound fertilizer at the rate of about 120 g per m (4 oz per sq yd), depending on your soil type. If it is very-light you can give a sprinkling of bonemeal and soot as well, to provide a long-lasting supply of nutrients.