Ag Minute: National Corn on the Cob Day

School’s out. As the calendar turns to June, signs of summer are all around. Days are getting longer, crops are in the ground, and strawberries are at their peak. One summer staple gets recognition on June 11th, which is designated National Corn on the Cob Day. While this special day comes a bit early to harvest sweet corn here in Central Illinois, fresh corn on the cob will be popping up at roadside stands and barbeques soon.

Corn is a crop that is native to the Americas. It has its origins in Ancient Mexico, where indigenous farmers selectively bred an edible wild grass called teosinte to create the first corn plant. According to Penn State University Extension, corn as we know it today falls into five classifications -- sweet, pop, flour, silage, or feed corn -- depending on the type of carbohydrate stored in the ear. Sweet corn has been bred to include genes that prevent or slow the normal conversion of sugar to starch during kernel development. In the early 1950s, a University of Illinois botany professor John Laughnan discovered a gene that made sweet corn even sweeter. Laughnan’s research revealed that the shrunken-2 (sh2) gene led to corn that produced kernels with less starch and four times more sugar than other sweet corn at the time. Laughnan started marketing his sweet corn with the sh2 gene and the “Illini Supersweet” hybrid was born.

The United States is the largest producer of corn in the world. Illinois is the second largest corn producing state, behind Iowa. Nebraska and Minnesota round out the top four. Combined, these four states contribute approximately 54% of the nation’s corn production. Surprisingly, sweet corn accounts for less than 2% of the corn grown in Illinois. Ninety-eight percent of the corn grown in Illinois is field corn. Popcorn makes up less than 1% of the corn grown in Illinois, which ranks third in the nation for popcorn production after Indiana and Nebraska. The top five sweet corn states based on value of production are Florida, California, Georgia, Washington, and Minnesota. The vast majority of corn grown in Florida is of the supersweet variety and can trace it roots back to Champaign-Urbana and Laughnan’s “Illini Supersweet” hybrid.     

Sweet corn is harvested during the “milk” stage, when kernels are fully formed but not fully mature and the juice in the kernel appears milky when punctured. This generally occurs 9 to 12 weeks after planting. Sweet corn remains in the milk stage for less than a week. Additionally, sweet corn tastes best when it is freshest, further complicating harvest planning. However, under ideal conditions, staggered planting allows for an extended sweet corn harvest period, from approximately the Fourth of July all the way through Labor Day, giving Sangamon County residents ample opportunity to enjoy some corn on the cob this summer.