Silking and pollination indicate approximately the midpoint in the development of the corn crop. Physiological maturity usually occurs 50 to 60 days after pollination. Kernel development usually is described by the milk, dough, and dent stages of development. Crop development is regulated by growing degree units and hybrid maturity rating. For an early medium-season hybrid (105-day), the growing degree days required to reach maturity from the early dough, early dent, and full-dent (all kernels dented) stages are about 660, 440, and 275, respectively. Late plantings and/or early frost can result in corn that becomes frosted before maturity.