Maturity

Growers should choose hybrids with maturity ranges appropriate for their geographic area or circumstances. Corn for grain should reach physiological maturity or “black layer” (maximum kernel dry weight) one to two weeks before the first killing frost in the fall. Use days to maturity and Growing Degree Day (GDD) ratings along with grain moisture data from performance trials to determine differences in hybrid maturity. Although yields of full-season hybrids often exceeded those of short-season hybrids in the past, early- to mid-maturing hybrids have been developed in recent years with yields comparable to those of full-season types. Late- to full-season hybrids do not always mature or dry down adequately before frost, which results in wet grain. When confronted with delayed planting or replanting decisions, growers may need to switch to early- to medium-maturity hybrids adapted to their area, but they should generally avoid short-season hybrids that are earlier than those normally used in their area. For more information on selecting hybrids for late planting, see the section on Date of Planting.