Dan Fillius
Commercial Vegetable and Specialty Crop Specialist
515-294-4249
fillius@iastate.edu
The middle of summer is officially here and so is sweet corn season. With the unusual weather events this year, Iowans can still expect to see an abundance of their favorite sweet corn variety.
Iowans in the southeast witnessed their first round of sweet corn on June 24. Four days later, producers were back in the fields harvesting larger amounts. In central Iowa, growers saw their share start trickling out of fields as of July 4.
In this article, Dan Fillius, field specialist for horticulture and commercial vegetables with Iowa State University Extension and Outreach, shares his insight on some basic sweet corn questions.
When is sweet corn the best?
In most years, Iowans can buy local sweet corn from roadside stands before it is available in stores. Sweetcorn being sold from the back of a truck bed has most likely been picked that same morning – making it exceptionally fresh and the best for supper that night!
When choosing your corn from the grocery store, the question of when it was picked is more complex. The kind of sweet corn available at grocery stores is either picked fresh daily with a new delivery every day from a local Iowa farm, or it is a supersweet variety that is going to hold its value for a week to 10 days.
“The corn that is in the grocery stores nowadays typically does not lose its quality for at least a week,” said Fillius. “It could be shipped from Florida during the off-season and many would be surprised to learn that it will still hold its flavor throughout transport. Supersweet corn can be picked and kept cool and still last a week to 10 days.”
The overall best option is to eat your sweet corn on the day of purchase. However, the sweeter the sweet corn variety, the longer it will keep without degrading.
When should I harvest sweet corn?
Sweet corn should be harvested at the milk stage. At this stage, the silks are brown and dry at the ear tip. When punctured with a thumbnail, the soft kernels produce a milky juice.
Overmature sweet corn is tough and doughy. An immature ear is not filled to the tip, and the kernels produce a clear, watery liquid when punctured. The harvest date can be estimated by noting the date of silk emergence. The number of days from silk emergence to harvest is approximately 18 to 23 days.
Prime maturity, however, may be reached in 15 days or less if day or night temperatures are exceptionally warm. Most hybrid sweet corn varieties produce two ears per plant. The upper ear usually matures one or two days before the lower ear. Lower ears are just as tasty as upper ears, however they are almost always smaller, making them less marketable for commercial producers.
How to keep your sweet corn fresh?
To prolong the life of your sweet corn, make sure to keep your ears cold and stored in the refrigerator. If your sweet corn is warm, the sugar is going to degrade faster, and the taste will not be as fresh. Also, be on the lookout for corn earworm. While you may be tempted to discard ears that have obvious worm damage, early season sweet corn this year is likely to have more worms than usual. Fillius said that Iowa farmers struggled with ear worm and other pests this year because of the unusual amount of rain and heat.
Remember Peaches and Cream?
Peaches and Cream is a common marketing term for bicolor sweet corn describing the yellow and white kernels. There used to be a popular variety named ‘Peaches and Cream’ that was grown and very popular, but it is not grown as much anymore.
Most of Iowa’s sweet corn today is not truly ‘Peaches and Cream,’ but rather this evocative term has turned into a local understanding of the sweetness one finds in delicious, bicolor Iowa sweet corn.
Grow your own sweet corn
Learn more about growing sweet corn in a recent Yard and Garden article called Growing Sweet Corn in the Home Garden. Additional information is available in a recent edition of Talk of Iowa, a show produced by Iowa Public Radio.
Shareable photo: Fresh ears of sweet corn
