When most of us think of corn, we think of the succulent cobs of sweet corn that we eat at as a vegetable. However, not all sweet corn is created equal.
While many gardeners are enjoying the new varieties of supersweets on the market, others crave that meaty “corn” taste of the older varieties that is somewhat missing from modern ones.
Regardless of which type you prefer, a little research on varieties will help you choose the best variety of corn not only for your own personal taste but also for your growing region.
Corn, Zea mays is thought to have originated from Central America where it was an integral part of the indigenous cultures. This original corn was grown until full maturity so that the kernels would fill with starch and could be used as a source of flour.
Today’s sweet corn is picked at a much more immature stage, before all of the sugars are converted to starch.
There are 3 main types of sweet corn, each with their own genetic characteristics:
- Su, or the normal sugary, make up the majority of heirloom and heritage varieties of sweet corn. They produce sweet, tender kernels that quickly loose their sweetness after harvest.
- Se, also known as sugar enhanced, have a higher level of sugar in their kernels that the Su types. While the sweetness lasts longer, they are best used within two days of picking.
- Sh2 stands for Shrunken 2 gene type. This type of corn is also called “supersweet” and contains a gene that prevents the conversion of sugar to starch. Because there is little starch in the seed, the kernels appear shrunken. Levels of sugar in the kernels are extra high and remain high for much longer periods of time after picking.
However, since the Sh2 types do not contain as much starch for young seedlings, they are more difficult to germinate. They require higher soil temperatures and difficult to grow in cooler areas where corn production is only marginal.
In addition, they need to be isolated from other varieties to guarantee the levels of sugar remain high. If pollen from other varieties pollinates an Sh2 type, the kernels tend to revert back to a field-corn type (not very tasty at all). Since corn is wind pollinated Sh2 should be planted at least 150 ft apart from other varieties. Make sure to take your neighbours’ gardens into consideration too.
Most corn needs a minimum soil temperature of 60 degrees F to germinate and grow. Corn development is very much temperature dependent. Hot days will decrease the time to maturity while cold days will increase it.