Sweet corn is a great crop to grow in a home garden and is a popular crop at local farmers markets. Before heading out to the garden plot, there are several things that people need to know about growing sweet corn.
Types of Corn
There are three types of sweet corn including regular sweet corn (su), sugar enhanced sweet corn (se), and supersweet corn (sh2). The industry uses the letters su, se, and sh2 to describe the types of sweet corn. For example, growers may see corn seed in a vegetable catalog listed as ‘Double Standard’ (su) or ‘Xtra-Tender 3473’ (sh2). In addition to these three types, synergistic seeds are also available. These seeds are a mixture of the sugar enhanced and supersweet types.
- Regular sweet corn is the type commonly planted by home gardeners. Of the three types of corn, regular sweet corn is the best to grow if the corn is going to be cooked the day it is harvested. This corn quickly turns starchy after harvest even if stored in refrigeration. Some popular examples of regular sweet corn are ‘Silver Queen’, ‘Merit’, and ‘Sweet G90’.
- Sugar enhanced sweet corn is not only sweeter than regular sweet corn, but it also holds its sweetness longer. This gives it a longer shelf life. ‘Silver King’ is a popular type of sugar enhanced sweet corn.
- Supersweet corn holds its sweetness longer than the other two types. It can be stored for up to 10 to 14 days after harvest with little reduction in the sugars. Supersweet corn has a shrunken look to the seed. The more sugar that is in a kernel of corn, the more it draws up or shrinks as it dries. Think of how field corn shrinks very little when dried. The supersweet corn seed are smaller than regular sweet corn and, therefore, are not as hardy. These seeds are more expensive than regular sweet corn seed by the pound, but because the seeds are smaller, it does not take as many seeds to plant the same size area. The supersweet corn seeds do cost more to plant and may not be available from every seed supplier. However, they can be found in many places and might be something worth trying on a small scale.
One of the first things that should be done in the garden before planting is having a soil test performed. A soil test gives an analysis of the nutrients that are in the soil and what a grower may or may not need to add. Sweet corn grows best at a soil pH level between 6.0 and 6.5. The soil test will show what the pH level is and what other elements need to be applied and when to apply them. If growers have not been testing their garden soils, and they need more information about it, they can contact their county’s Extension office.
Many people plant too early, trying to make an early crop. Different corn has different days to maturity. The seed catalogs and/or seed packet will list the days to maturity. Planting time is important in regard to supersweet corn. People may not get a good stand if the soil temperatures fall below 60o F after planting. For this reason, many growers will plant sugar enhanced sweet corn early in the year and supersweet corn at later plantings when the ground is warmer. The synergistic corn will do better in cooler temperatures than the supersweet corn will. Many seed catalogs list temperatures for good seed germination.
Growers should avoid cross-pollinating regular and sugar enhanced sweet corn with supersweet corn. For this reason, supersweet corn should be planted 300 feet or more from regular or sugar enhanced sweet corn. If growers cannot separate them by distance, they should find out the days to maturity for the different types of corn and plant them so that they will silk two weeks apart. Corn begins to show silks at 18 to 22 days before it is mature and ready to harvest. The planting distance is not as important with regular and sugar enhanced sweet corn, but they should be separated if possible.
There are many sugar enhanced and supersweet corn varieties. People can find yellow, white, or bicolor in the su, se, and sh2 corn types. People sometimes use the word “variety” when discussing all seeds, but cultivar is the correct term when discussing hybrid seed. Growers can find some GMO corn seeds, but none of the corn cultivars listed in this article are GMO.
Some recommended sugar enhanced sweet corn varieties include the following:
- ‘Silver Princess’
- ‘Sweet Ice’
- ‘Silver King’
- ‘Honey Select’
- ‘Precious Gem’
- ‘Sweet Chorus’
- ‘Sweet Rhythm’
Some recommended supersweet corn cultivars include the following:
- ‘Awesome XR’
- ‘Seminole Sweet XR’
- ‘Superb MXR’
Many other cultivars of sugar enhanced and supersweet corn are available. If people want to try a new corn and cannot find one of the recommended cultivars, they should not be afraid to try another cultivar. When trying different types of corn, people should plant a little at first to see if they like it before planting their entire garden or field. Different types of sweet corn have different tastes, shelf life, and require different management inputs. Growers need to pick which corn best suits their needs.
To maintain the sweetness of the sweet corn, cool it quickly after harvesting. People can place the corn in an ice bath then place the cooled corn in the refrigerator. Sweet corn stores best at approximately 32 o F.