Even though the 4th of July is already behind us and summer is in full swing, there is still plenty of time to get all your favorite varieties of corn planted for a late season harvest. Most varieties of corn are ready to harvest at about 3 months and can be sown as late as 90 days from your first regional frost. Corn is a member of the tenacious grass family and, anyone who’s grown it, knows it’s nearly effortless to maintain. Along with fast-growing leafy greens and roots crops, corn is popularly grown successively throughout the year for replete harvests and season-long grilling.
While you’ve probably tasted and seen for yourself that not all corn is the same, here are the different types of corn you’ll experience both in and out of the garden. Regardless of the type you’re growing, be sure to only grow like crops with like crops to keep from cross-pollination spoiling both crops such as (su) with (su); ornamentals with ornamentals.
Normal Sugary (su)
- 8-10% sugar content
- High productivity and harvests
- Best if enjoyed within 24 hours
- Do not plant near (se), (sh2), (syn), and (orn)
Sweet corn types known as normal sugary (su) contain an average 8-10% sugar content and were the only type available prior to the advent of commercial crossing and hybridization in the early 1900’s. Normal sugary (su) types are generally not ideal for farmers’ markets or resale because they do not store well and the sugars are known to quickly turn to starch within just a day of being plucked from the garden. Although not as sugary as supersweet (sh2) varieties, normal sugary (su) is preferred for its abundant harvests, serving as the parent for less reliable hybrid crops. Normal sugary types of corn grow far more vigorously than specialty hybrids and are an ideal choice for late season sowing.
Sugary Enhanced (se)
- 16-18% sugar content
- Medium productivity and harvest
- Best if enjoyed within 3-5 days
- Do not plant near (su), (sh2), (syn), and (orn)
Most commercial and store-bought ears of corn are likely a type of sugary enhanced (se) because they boast a higher 16-18% sugar content which is directly responsible for their longer shelf life. While sugary enhanced (se) types still convert their sugars to bitter starch, the process takes several days longer than normal sugary (su) varieties simply because there is more sugar to convert. Sugary enhanced (se) corn is the resulting hybrid from preferred (su) and (se) types and sometimes is designated with a (se+) if both parents are sugary enhanced. Like most varieties of corn, sugary enhanced (se) generally is ready to harvest in about 90 days and can be started as late as 90 days from the first frost.
- 30-35% sugar content
- Low productivity and harvests
- Best if enjoyed within 7-10 days
- Do not plant near (su), (se), (syn), and (orn)
Known by a number of names including extra sweet, ultra sweet, or shrunken-2, this commercial favorite is grown exclusively for its unparalleled 30-35% sugar content and inability to convert these sugars to starch. Although it is the absolute sweetest type of corn available, supersweet (sh2) types are understood to be the most difficult to grow while also lacking the robust harvests of more standard (su) and (se) types. While sweetness and flavor of (sh2) is difficult to match, the quantity and productivity may leave you wanting a less sugary, more reliable corn crop. The name shrunken-2 (sh2) refers to the appearance of the kernel which is noticeably shriveled and shrunken when dried, allowing all (sh2) types to be easily recognized by the naked eye.
- 20-35% sugar content
- Medium productivity and harvests
- Best if enjoyed within 5-7 days
- Do not plant near (su), (se), (sh2), and (orn)
Although not as popular as other cultivars, the synergistic (syn) type is a supersweet hybrid that shares one sugary enhanced (se) parent and one supersweet (sh2) parent in a ratio of about 75/25, favoring the productivity of the more vigorous (se) parent. Synergistic (syn) corn delivers the reliably high sugar content of supersweet (sh2) crops while ensuring larger harvests, more characteristic of (se) varieties. The synergistic (syn) has become a new standard among home gardeners interested in trying supersweet (sh2) varieties while still getting the most value from their garden bed. Synergistic varieties mature in about 80 days and can be sown as late as July for autumn harvests.
- 0% sugar and inedible
- High productivity and harvests
- Can be stored for up to 4-6 months
- Do not plant near (su), (se), (sh2), and (syn)
Perhaps second to pumpkins and other winter squash, nothing says cool autumn days like bright and seasonally colored ornamental corn. While edible varieties all share traditional yellow and white kernels, ornamental crops are grown exclusively for their exotic color combination which can be harvested whole, stalk and all, for authentic seasonal décor. Brightly colored ornamental crops generally have no culinary value, but the dried corn kernels can be traditionally ground into a powder for food dyes in breads and tortillas. Ornamental corn will store for several months because they do not contain any sugar content at risk of converting to starch. Be sure not to plant ornamental varieties of corn near edible types to keep from cross-pollinating and spoiling both crops.