By Ajay Nair–Iowa State University Extension and Outreach
AMES, Iowa – Warmer temperatures are in the forecast and some sweet corn growers may be getting ready to plant their first crop.
While producing early sweet corn is attractive, especially when it can be harvested by the July 4 holiday, early corn also comes at a risk.
In a recent article in the Acreage Living Newsletter, Ajay Nair, associate professor in horticulture and extension vegetable production specialist with Iowa State University Extension and Outreach, explains the challenges and risks of growing early sweet corn.
“Every year growers try to push the boundaries of early planting to have sweet corn ready by July 4,” said Nair. “It is a risky proposition as there is risk of frost late April and early May.”
For sweet corn, higher and uniform germination rates are observed when soil temperature is close to 55 degrees Fahrenheit, according to Nair. Some cultivars such as shrunken-2 and augmented supersweet should be planted later in the season when soil temperatures are close to 60 F. The minimum is considered to be 50 F, but each variety is different and some will not do well below 60 degrees.
Temperature for corn is often calculated in terms of growing degree days or GDDs. This is a calculation of the average daily temperature and includes a minimum development threshold that must be exceeded for growth to occur.
In the article, Nair explains how to interpret GDD requirements and how to plant the crop in successive plantings, so that it will ripen throughout the growing season.
If succession planting is done properly, and depending on fall conditions, Iowa growers can produce fresh sweet corn into mid-September. By paying attention to the GDDs and other scientific data about each cultivar, growers can do a better job of targeting their planting and harvesting dates, and reducing the risk of loss.
Sweet corn is a significant specialty crop in Iowa. Based on the 2017 Agriculture Census, sweet corn was planted across 329 farms with a collective acreage of 2,739 acres. Of the total acres, 1,743 is harvested for fresh market and the remainder for processing.
“Sweet corn is sort of that hallmark vegetable for Iowa and many people look forward to it because they grew up with it,” Nair said.
Other articles in this month’s Acreage Living Newsletter cover ventilation concerns with small-scale livestock production, managing beef cattle and mud, and monitor over-wintering population.
For more about sweet corn, Nair can be reached at 515-294-7080 or [email protected].