Q: What are the guidelines for growing sweet corn?
A: Nurseries and garden centers have several varieties to try. Seed catalogs have old standards and many new varieties each year.
The best-tasting variety is a matter of personal preference, so try a different variety each year. The early varieties are very popular but not as good-tasting as the later ones.
New varieties, called “extra sweet” or “super sweet,” have about twice the sugar content of regular sweet corn and can hold their sugar content longer after being picked. Golden corn is the most familiar color, but two-color and white are considered the sweetest and best-tasting. The early varieties grow the shortest, about 4 to 5 feet, and can be spaced about 8 inches apart, but the plants produce only one fairly small ear.
Midseason varieties grow 5 to 7 feet tall, and the late or main-season crop gets 7 to 8 feet tall and should be spaced about 10 inches apart. This one produces two large ears. If you plant several hybrid varieties close to each other, they will cross-pollinate and the result may not be as good as field corn. The difference in time to maturity varies from six to seven weeks for early varieties, eight to 10 weeks for midseason and 12 to 13 weeks for a late-season crop.
Preparation: Sweet corn is second only to tomatoes in popularity for home gardeners. Select a site that has lots of sunshine and is free of weeds. Prepare the bed by watering, and when the soil has dried to be just moist, for each 100 square feet add 3 pounds of 16-20-0, 3 pounds of sulfur, 3 pounds of Ironite and 3 to 4 inches of mulch or compost. Mix it all together, water it again well and plant when the soil is lightly moist.
Planting: Do not plant in a single row because there will not be enough pollen to fill the ears. Plant in blocks of four rows or in clusters of four to five plants. Soak the seed for three to four hours before planting to save several days in germination. Plant each kernel about 1 inch deep, 4 to 6 inches apart in clusters of four to six plants, with 20 inches between. Or you can plant in a small circle with 16 to 20 plants. If you make successive plantings about three weeks apart you will have sweet corn well into the summer.
Water and fertilizer: Sweet corn is the most demanding for watering and fertilizer of almost all the food we grow in the home garden. If the plants are stressed due to lack of either, your sweet corn will be disappointing, so never let the soil completely dry out. When the plants reach the four- to five-leaf stage, or about knee high, fertilize with nitrogen. Nitrogen fertilizer includes blood meal (15 percent), use 1 pound per 100 square feet; ammonium sulfate (21 percent), use 1/2 pound per 100 square feet; ammonium nitrate (34 percent), use 1/3 pound per 100 square feet; or urea (45 percent), use 1/4 pound per 100 square feet. Take your choice, but apply it weekly and just enough to keep the leaves dark green. Apply it until the tassels and silk appear.
Harvesting: Corn is ready to about 20 days after the first silk shows; the warmer the weather, the sooner you can pick it. When the silk dries and turns brown, it’s about right. Use two hands to harvest — one hand to hold the stock and other to pull down and break off the ear.