Published 12:00 am Friday, July 1, 2011

SALISBURY — Nothing speaks the arrival of summer more than enjoying fresh, local, sweet corn.
On the cob, grilled or stewed, it’s a favorite at local farmers markets and roadside stands. Early July is the peak for sweet corn in Rowan County and producers are crowing about their bumper crop.
Nobody really knows when sweet corn originated, but it was grown by the American Indians and first collected by European settlers in the 1770s.
Sweet corn mutated from standard corn or dent corn. This mutation allowed the storage area of the kernel to accumulate about two times more sugar than field corn.
Through selective breeding and research, several hundred sweet corn varieties are available. Sweet corn varieties have three primary colors: yellow, white and bicolor (yellow and white). Although there are geographical preferences for certain kernel colors, there is actually no relationship between color and sweetness.
Some producers plant sweet corn in early April and try to get a jump on the season. Some gamble with corn transplants grown in paper cups started in a greenhouse. Silver Queen is a white sweet corn and is considered by many the standard sweet corn in Rowan County. However, Silver King has become a very popular variety for Rowan consumers.
Savvy producers capitalize on the popularity of an early crop and will continue to plant sweet corn every two weeks through July. Staggered sweet corn plantings are essential for a continual harvest through August and possibly into September.
Sweet corn is very difficult to grow in late summer, even for the most confident growers and nearly impossible for home gardeners. Lack of consistent irrigation and massive insect infestations of corn earworm and European corn borer makes production prohibitive to most.
Growers implement routine sprays of special insecticidal formulations containing Bt’s, (Bacillus thuringiensis) designed to kill immature late season worms. This insecticide contains a naturally occurring bacterium that is safe for humans but deadly to corn earworms and other corn loving larva. Constant sprays are a must to keep worm levels at an acceptable level for customers.
Sweet corn is very perishable, losing its sweetness and freshness rapidly after harvest; the rate of loss increases with increasing temperature. Dented corn kernels indicate the corn is not fresh.
Most growers harvest sweet corn early in the morning or the night before when the temperatures are 10 to 20 degrees cooler than later in the day. Look for light, almost sticky silk to indicate freshness.
Sweet corn needs to be refrigerated as soon as possible. Delaying refrigeration allows the accumulated sugars to be converted to starch, and subsequent loss of that sweet corn flavor. Take it home and eat it as soon as possible. You won’t regret it.
Darrell Blackwelder is county extension director for the Rowan County Center of the North Carolina Cooperative Extension. Contact him at 704-216-8970 or or