Corn needs a very fertile soil. The region must have adequate rainfall, but springtime must not be too wet or too cold. Corn grows best in regions where both days and nights are warm, and where rain comes in showers, followed by sunshine.

Because the corn plant takes large amounts of nutrients out of the soil, corn crops are usually rotated with other crops to prevent exhausting the soil. A common method of crop rotation is to plant corn for two years, oats the third year, and sweet clover the fourth year. The clover is plowed under to enrich the soil still further before the corn cycle begins again.

Liberal amounts of commercial fertilizer or manure are applied, either in bands on both sides of the newly planted corn, or spread over the land before plowing.

The soil is plowed to a depth of about six inches (15 cm) or more. The seedbed is disked and harrowed, but the soil is not broken up too finely. In the United States, mechanical planters, called wheel-track planters, are widely used; they dig the furrows, distribute the seeds in the furrows, and cover the seeds with soil. Corn is usually planted in rows 24 to 36 inches (60 to 90 cm) apart.

The soil around the growing corn must be stirred up to kill weeds. Corn fields are cultivated three or four timesuntil the plants grow too large to permit a tractor to pass among them. Chemical weed killers have been used effectively in corn fields, but they do not entirely eliminate the need for cultivation.

The method of harvesting depends on the type of corn. In the United States most corn grown for its grain is harvested by machine. The machines snap the ears off the stalk and deliver them to wagons. Some mechanical pickers remove the husks after picking; others do not. The picker-sheller picks the corn, removes the husks, strips the grain from the cobs, and delivers the grain into hoppers.

Corn grown for silage is harvestedstalk, leaves, ears, and alland cut into half-inch (1.3-cm) lengths. It is stored in a silo for winter cattle feed. In harvesting corn for fodder, the entire plants are taken, gathered into tepee-shaped piles called shocks, and allowed to cure in the field. Sometimes fodder corn is left standing and cattle or hogs are turned into the field. Livestock gleaning is also useful to salvage ears left behind by the picking machines.

Harvested corn must be dried to prevent it from spoiling. The ears are exposed to the air in slat-wall cribs, or are dried by mechanical or electrical dryers and heaters. Stored corn is subject to attacks by insects, rats, and mice. These pests are combated by proper design of corn cribs, by fumigation, and by poisons.