April 17, 2009
Guidelines for Late Planting of Small Grains and Corn
Small grains are cool-season crops that require relatively cool temperatures to
achieve high yield potential. Therefore, when planted late, small grains develop
during warmer temperatures that are detrimental to yield.
When planting is delayed beyond the last optimal planting date, yield reductions
accelerate and profitable crop production becomes risky. Full insurance coverage
is available until June 5 in northern-tier counties and until May 31 in all
other counties. Of the small grains, oats is the most tolerant to late planting
and barley the least tolerant.
When planting is delayed beyond the optimum date, it may be beneficial to
increase the seeding rate by 1 percent per day of delay up to a maximum of about
1.6 million seeds. This increase will compensate partially for the decrease in
grain yields associated with reduced tillering that occurs when plants develop
in warmer rather than optimum temperatures.
Corn is a warm-season crop and requires warmer temperatures than small grains
before it will germinate and grow.
The main concern with late-planted corn is that it will be at risk of being
killed by frost before it reaches physiological maturity, so yield and grain
quality will be reduced. Delayed planting also increases the probability that
the harvested grain will be wet, difficult to handle and expensive to dry.
The recommended planting date for corn in all regions of the state is May 1,
with little negative impact most years and locations if planting is delayed
until May 20. However, the recommended maturity of the hybrid to be grown varies
significantly by location.
