Anything that interferes with the pollination process in sweet corn will cause kernel deformities or crop failure. Sweet corn produces tassels or silk and each strand is attached to the inside of the ear and produces one kernel. Therefore, each strand in the corn tassel must be completely pollinated to make a perfect kernel along the ear.
Not Enough Sweet Corn Plants
Sweet corn needs plenty of other sweet corn plants around in order to get complete pollination. If there are not enough sweet corn plants, then pollination will not occur. Also, sweet corn must be planted in blocks.
Making long single rows separated by a pathway will prevent the corn plants in one row from pollinating another. Keep in mind that corn is wind-pollinated so planting corn the correct distance apart, is important.
It is best to plant several rows, with each row containing three or four smaller rows of sweet corn planted 9-12 inches apart and each of those rows separated by a pathway 24-36 inches wide for access to the crop.
Not Enough Fertilizer
Corn is a type of grass that needs plenty of nitrogen and moisture to grow. When there is not enough fertilizer or the wrong type of fertilizer is used, the plant cannot grow rapidly and produce large ears with thick tassels that are needed to produce top quality ears of sweet corn.
Insects such as corn ear worms, or any insect that chews tassels away from the ear of corn, will cause problems with pollination because the silk strands cannot pollinate the new corn kernels so they can form correctly.
Another Type of Corn Nearby
Different types of corn must be planted more than 1,000 feet apart to prevent cross-pollination. When sweet corn cross-pollinates with another type of corn sweet corn kernels can be bitter, deformed or non-existent.