Generally speaking, modern corn grows only one year in a season. This is due to large amounts of biological evolution, with the hopes of growing one high quality ear as opposed to several very low quality ears. There are the occasional stalk that will grow 2 ears, but with the modern strain of corn, this is considered a genetic defect. Some varieties of sweet corn will grow three or four ears. There is also a variety of sweet corn that has been known to grow 6 ears. The greater yield from the sweet corn is due to the shorter growing season and the smaller size of ears on the sweet corn, with the 6 ear plant giving the smallest ears.