In last week’s C.O.R.N. newsletter, Peter Thomison provided useful information on tools available for switching corn hybrids (https://agcrops.osu.edu/newsletter/corn-newsletter/2019-15/more-switching-corn-hybrid-maturities). As Dr. Thomison points out, Dr. Bob Nielsen at Purdue University wrote an article describing the U2U Corn GDD Tool, available from the Midwest Regional Climate Center (https://mrcc.illinois.edu/U2U/gdd/), with caveats to keep in mind as one is making their decisions. Specifically, users are encouraged to modify their black layer GDDs within the tool in order to reflect a more accurate assessment of days to maturity.
To aid in these decisions, we have provided two maps below showing the average median date of the first fall freeze (based on 1981-2010 conditions) for selected sites across Ohio. Figure 1 shows the median date based on 32°F and Figure 2 shows the median date based on 28°F. Figure 1 shows that most of Ohio experience the first 32°F date between October 11 and October 20, with a freeze occurring prior to this period for some locations (dark green circles). The average first date for 28°F occurrence in the fall is between November 1 and November 10 (Figure 2; brown circles), with many sites across West Central, Northwest, and East Central Ohio indicating dates as early as October 21.
This and other important agricultural-related data may be found at the Midwest Regional Climate Center (https://mrcc.illinois.edu/cliwatch/special_topics/agriculture.html).