Ask an Agronomist
Is it too late to plant full-season corn hybrids?
May 08, 2014
Question: I feel like it’s getting pretty late to plant my full-season corn. What are you telling growers?
Answer: As prospects for a timely start to spring planting diminish, growers need to reassess their planting strategies and consider adjustments. Since delayed planting reduces the yield potential of corn, the foremost attention should be given to management practices that will expedite crop establishment, wrote Peter Thomison and Steve Culman, with Ohio State University Extension in a recent CORN Newsletter. Although the penalty for late planting is important, avoiding tillage and planting operations when soil is wet should be a higher priority. Yield reductions resulting from ‘mudding the seed in’ are usually much greater than those resulting from a slight planting delay. Yields may be reduced somewhat this year due to delayed planting, but effects of soil compaction can reduce yield for years to come. Keep in mind that we typically don’t see significant yield reductions due to late planting until mid-May or even later in some years. Don’t worry about switching hybrid maturities unless planting is delayed to late May. If planting is possible before May 20, plant full-season hybrids first to allow them to exploit the growing season more fully. Research in Ohio and other Corn Belt states generally indicates that late plantings of earlier maturity hybrids are less susceptible to yield losses than late plantings of the later maturing, full-season hybrids. And, as the planting season drags on, optimal seeding rates for the yield potential of each field should be used. Recommended seeding rates for early planting dates are often 10% higher than the desired harvest population because of the potential for greater seedling mortality. However, soil temperatures are usually warmer in late planted fields, and as a result germination and emergence should be more rapid and uniform. So, as planting is delayed, seeding rates may be lowered (decreased to 3% to 5% higher than the desired harvest population) in anticipation of a higher percentage of seedlings emerging.