Sweet Corn Types & Isolation Requirements

Sweet corn falls into two broad groups, sweet and super sweet, which include five sub-types worth knowing. The type affects flavor, texture, how long ears stay sweet and how far you need to isolate plantings, so it pays to know the types when choosing varieties.

Sweet Corn

Within the sweet group you'll find three kinds: normal sugary, sugary enhanced and synergistic.

• Normal Sugary (su)

  Normal sugary (su), sometimes called standard sugary, tastes like the corn of decades past. The sugar converts to starch fast once ears are picked, so plan to eat them within a day or two. These open-pollinated types are less uniform and less tender than today's hybrids. Plenty of eaters prefer that chewier, old-time character, but try a small block first if you haven't grown it. For this type we offer ‘Double Standard’.

• Sugary Enhanced (se) and (se+)

  Sugary enhanced (se) corn has an extra gene that boosts the standard sugary gene, giving sweeter, more tender kernels. Starch conversion is slower after harvest, so ears hold a bit longer than su corn if kept close to 32°F. When just one parent contributes the gene the hybrid is called heterozygous se; when both parents do, it is homozygous, labeled se+, and noticeably sweeter. For this type we offer the se+ variety ‘Sugar Buns’.

• Synergistic (syn)

  In synergistic (syn) corn, roughly three of every four kernels on an ear are se and one is sh2, so you get se tenderness with some sh2 snap. Give the kernels time to fill out before harvest. Starch conversion is slower still, and syn ears kept close to 32°F stay sweet and crisp for as long as 5 days. Syn varieties we offer: ‘Allure’, ‘Essence’, ‘Illusion’, ‘Latte’, ‘Montauk’, ‘Quick Start’, and ‘Temptress’.

Super Sweet Corn (sh2)

Super sweet corn is sweeter than most other types, and its sugars turn to starch more slowly after picking, so ears can stay sweet and crisp for 5–10 days when held near 32°F. Breeders keep working to improve super sweets and release new varieties, focusing mainly on the genes behind their flavor and texture. One of these naturally occurring genes is shrunken-2 (sh2), named for the shriveled look of the dry seed. Hensley’s carries a wide range of super sweet varieties.

Isolation

Certain corn types shouldn't cross-pollinate, because crossing can make kernels starchy, tough and poor tasting. Keep super sweet corn isolated from every other type of corn, and keep synergistic corn isolated from super sweet, field and popcorn.

You can isolate by distance, by maturity date, or both. If you grow types that need to be kept apart, use any of these methods:

1. Keep varieties at least 300' apart.
2. Sow at least 12 days apart and keep the plantings at least 25' apart.
3. Choose varieties whose maturity dates differ by at least 12 days and keep the plantings at least 25' apart (for example, sow 'Kickoff XR' (67 days) and 'Montauk' (81 days) on the same day, 25' apart).

Learn More

• Sweet Corn Varieties  • PDF comparison chart
• Old-fashioned sweet corn • Growing information
• Sweet Corn  • Growing information
• Super sweet corn  • Growing information
• Growing super sweet varieties  • PDF tech sheet