Normal sugary, sugary enhancer and supersweet are three classifications of sweet corn varieties. Standard sweet corn is classified as normal sugary. Standard sweet corn varieties prefer a soil temperature of at least 55 degrees Fahrenheit. Supersweet varieties germinate well when the soil reaches 65 F or above.
The Earlivee sweet corn variety matures in 58 days and produces 7-inch to 14-inch ears of yellow corn. An early bicolor is the Quickie, which matures with white and yellow kernels in 64 days. A very early white corn variety is Spring Snow. The variety requires about 65 days to reach maturity.
Precocious, a sugary enhancer variety, produces 7-inch to 12-inch ears in 66 days. A supersweet variety, Early Xtra Sweet produces 8-inch ears in about 70 days. Supersweet varieties must be separated from other corn varieties by 500 feet. Pollen from other varieties can make the corn tough and starchy.