Corn crop sunk by lack of hot days

As the summer of 2004 slipped into autumn Wednesday, it took with it the last opportunity to salvage that traditional late-summer harvest—sweet corn.
Anyone who tried to grow it in Rainy River District does not need to be reminded that this year qualified as a failure as far as the harvest has been concerned.
“The backyard sweet corn guys are probably not going to make it this year,” said Gary Sliworsky, district rep for the Ontario Ministry of Agriculture and Food in Emo.
So what went wrong?
Quite simply, it’s all about the heat—or lack thereof. It just never got hot enough for long enough to give the corn a chance to mature.
Corn is one of those crops that does not ripen unless it receives a minimum amount of heat over its growing period—regardless of the amount of rain or other factors.
A typical hybrid variety that grows in this area requires 60 days from germination to harvest and, according to Sliworsky, it must receive a minimum of 2,200-2,400 Corn Heat Units.
CHUs are calculated from the time the soil is warm enough to support germination (15 C) until the end of the growing season.
Kim-Jo Bliss, agricultural technician at the research station in Emo, said the number of CHUs accumulated this year was substantially below last year’s total.
By Aug. 31, Bliss had recorded only 1,638 CHUs compared to 2,320 at the same time last year. In fact, this year’s total was the lowest recorded in the last five years.
The best year in that period was 2001, when Bliss recorded 2,344 CHUs by Aug. 31.
The reason was two-fold. Because of the cool spring, the soil did not reach the temperature for calculations to begin until June 3, which was by far the latest start.
The only other year that came close was 2002—the year of the flood—when calculations began on May 30. That year ended up being the second-coolest in the last five, yielding only 1,857 CHUs by the end of August.
By comparison, calculations commenced on May 9 last year, April 28 in 2001, and on April 27 in 2000.
As such, the only way to get well-ripened corn this year was to import it from southern Minnesota, where the summer was both warmer and longer. But even there, things were cooler than usual.
Doug Hartwig is the director of the Agricultural Statistics Division at the Minnesota Department of Agriculture, an agency that also keeps track of heat during the growing season, except that there the units used are Growing Degree Days (GDD).
These units are calculated from a complex formula using slightly different criteria, but the result is similar to CHUs.
Hartwig said the GDD for the Borderland region of Minnesota worked out to around 1,800 by the end of August, whereas in the state’s southern agricultural region around Worthington and Mankato, the numbers were high enough to produce a decent corn crop.
So, if you’re wondering where the corn is, don’t hold your breath. And as far as next year is concerned, it all comes down to the heat.