Poorly filled ears result from ineffective or incomplete pollination. Pollen grains produced on the tassels must fall on the sticky silks for complete pollination. Each strand of silk is attached to a kernel, so for each silk that is pollinated, one kernel will develop on the ear. Corn pollen is spread by the wind; if the wind is blowing across a single row of corn, the pollen on the tassels will be carried away from the silks, resulting in poorly filled ears. Poor pollination can also result from dry soil during pollination and from hot, dry winds. Prolonged periods of rain reduce the amount of pollen shed from the tassels. Damage to the silks from corn earworms (see Corn Earworm), rootworm adults (see Corn Rootworm), armyworms (see Armyworm), and grasshoppers (see Grasshoppers) may also result in incomplete ears.
To help ensure pollination, grow corn in blocks of at least 3 or 4 short rows rather than in 1 long row. Plant seeds 12 to 16 inches apart in rows 30 to 36 inches apart. Keep the soil moist, letting the surface dry slightly between waterings. Control corn insect pests. Corn can be hand-pollinated by shaking the tassels onto the silks.
Plant Care for Corn