Home gardeners can choose from numerous sweet corn varieties. Sweet corn varieties differ in color (yellow, white, bicolor), sugar content, texture, ear size, days to harvest, and other characteristics.
There are five main types of sweet corn available to home gardeners. These types vary in sugar content, texture, length of harvest period, storage life, seed vigor and germination requirements. The five main types of sweet corn are standard sugary (su), sugary enhanced (se), supersweets (sh2), synergistic (syn) and augmented supersweets (shA or aug). Within each of these major types are cultivars that will ripen in the early, mid and late seasons.
Standard sugary (su) cultivars have been grown for many years. These cultivars have the traditional sweet corn flavor and texture. Sugar levels are generally between 10 and 15 percent at harvest. Unfortunately, ears of sugary cultivars retain their high quality for only 1 or 2 days. Also, standard sweet corn cultivars don’t store well as sugars quickly convert to starch after harvest. Seeds germinate well at soil temperatures of 55 to 60°F.
Sugary enhanced (se) cultivars contain the sugary enhanced gene that produces ears with sweet, tender kernels. Compared to su cultivars, sugar levels of se types are higher and the storage life is 1 to 2 days longer. Seeds germinate well at soil temperature of 55 to 60°F.
Supersweet (sh2) cultivars contain the shrunken-2 gene. These cultivars have very high sugar levels, and convert sugar to starch slowly, allowing for a longer harvest period and a storage life for up to one week with refrigeration. The seedcoats on kernels are rather thick, giving the corn a firmer, crunchy texture. Soil temperatures need to be at least 60°F for optimal germination.
Synergistic (syn) sweet corn varieties combine the desirable traits of standard, sugar-enhanced, and supersweet varieties. Synergistic sweet corn varieties are sweet, creamy, and tender with an excellent storage life. Seeds germinate well at soil temperature of 55 to 60°F.
Augmented supersweet (shA or aug) sweet corn varieties are supersweet types that also have the se trait in all their kernels. These varieties are sweet, tender, and have a long harvest period with excellent storage life. Soil temperatures should be at least 60°F for optimal germination.
Learn more about different sweet corn varieties from Dan Fillius, Commercial Vegetable Production Extension Specialist.