Sweet Corn is adapted to a wide range of climatic conditions and, consequently, is grown in all sections of the U.S. It is grown for the fresh market in both the southern and northern regions, but by far the largest acreage in the North is grown for processing and freezing. This crop grows best during hot weather and is frost-tender.
Sweet Corn Varieties
Each seed company lists many varieties; therefore it is difficult to suggest varieties that are available in all sections. Most of the older varieties such as ‘Golden Bantam’ and ‘Country Gentleman’ have been replaced by hybrids such as ‘Sugar and Gold’, ‘Golden Beauty’, Earlibelle’, ‘Butter and Sugar’, ‘Gold Cup’, ‘Golden Cross Bantam’, and ‘Jubilee’, listed in order of maturity. ‘Country Gentleman’ and ‘Stowell Evergreen Hybrids’ are popular white varieties. There are many other varieties that are excellent and therefore it is recommended that seed catalogues be checked for those that are listed for a particular region.
Sweet Corn Soils and Fertilizers
Sweet Corn is grown on all types of soil. A well-drained sandy loam to a silt loam is preferred. This plant has a very deep and extensive root system. Deep and thorough soil preparation is therefore important. Three to four bu. of well-rotted manure per two ft. of row worked into the soil will improve the water-holding capacity of the soil and provide some plant food.
Sweet Corn Planting
Sweet Corn is injured by frost and the seed germinates poorly in cold wet soil. Planting should be delayed until these conditions are satisfactory. Some gardeners start the seed in paper bands or pots in the hotbed and then transplant into the garden to get corn a week or two earlier than by direct planting out of doors. Sweet Corn can be planted in hills or in drills. Hills should be spaced 18 to 24 in. apart in the row and the rows spaced at 36 in. Three plants are adequate per hill. In drills the rows are spaced at 36 in. and the plants thinned to stand6-8 in. apart. Crows and starlings may scratch out the seed just prior to its germination. The seed should be treated with a crow repellent which can be purchased at a garden center.
Sweet Corn Cultivation
Cultivation of Sweet Corn is similar to that of other garden crops, namely shallow and sufficient to control weeds. Where corn is planted in hills, black plastic 18 in. wide may be placed over the row with holes for each hill. This not only controls weeds but also tends to conserve soil moisture. Herbicides are widely used in commercial corn plantings for the control of weeds. The most satisfactory material is Atrazine, but again this is very selective and cannot be recommended for the home gardener with a few short rows of Sweet Corn.
The removal of suckers and hilling of corn plants is not necessary or recommended Harvesting
Highest quality, sweetness and tenderness of the kernel are reached when harvested in the milk stage of maturity. At this stage the kernel is soft and succulent. As the kernel content changes to a doughy consistency it loses its sweetness and increases in toughness. Flavor and succulence are quickly lost after picking if exposed to high temperatures, say 75° to 80° F. At these temperatures 30-50% of the sugar may revert to starch in 4-5 hours. At temperatures of 32°-38°F, the original quality may be retained for several days.
Sweet Corn Insects and Pests
Corn earworm, a stout striped worm, feeds in the silk and kernels near tip of ear. Although they do not survive freezing, they migrate northward and are destructive when the ears are maturing. Spraying or dusting the silk at 2 or 3 day intervals with insecticide is safe and effective. European corn borer and southern corn borer tunnel stalks and eat kernels. Spraying with insecticide when the stalks are first visible in the whorl and repeating in 7-10 days should give good control. White grubs and wireworms eat the seed and roots and soil treatment with insecticide is desirable following sod. Corn flea beetle spreads bacterial (Stewart’s) wilt disease and, following mild winters when the beetle survives, a careful spraying program with insecticide on early corn is recommended. Army worm can strip the leaves from corn in a short time. They are most destructive in late summer and a thorough treatment of corn and surrounding vegetation with insecticide is advised. Chinch bug is destructive in Midwestern corn fields but seldom needs special control in home gardens. Stalk borer bores into stalks when they are small and ruins them. Spraying is seldom practical. Japanese beetles eat the silk but can be handpicked successfully if sprays for other insect pests are not used.
Sweet Corn Diseases
Bacterial wilt is described under flea beetle. Corn smut produces large, grayish-white galls called “boils” which usually ruin the ear. The “boils” contain a mass of spores. Fungicides are impractical and cutting and burning before the spores mature is suggested for home gardens. Treated corn seed is recommended for planting using fungicide on home grown seed.