Sweet corn is fairly easy to grow in an area with full sun and fertile soil. The sweet corn varieties available to home gardeners are hybrids. Some varieties available include standard (su) and sugar enhanced (se), both are open-pollinated and need ample space to prevent one variety from damaging the quality of another. Sweet corn and other corn types require complete isolation to avoid cross-pollination.
Spacing for Sweet Corn Varieties
Because sweet corn is open-pollinated, all varieties can act as pollinators for one another, so give each variety of sweet corn at least 250 feet of space between varieties. Corn is wind-pollinated, so at this distance, the wind is unlikely to carry pollen far enough to affect the different varieties and if it does, it is unlikely to be enough pollen to cause contamination. For complete isolation, to ensure no cross-pollination takes place, leave 700 feet between each sweet corn variety, the distance generally used in plant breeding.
When growing sweet corn, you can also use a method known as staggered planting. Plant each type of sweet corn two weeks apart up until the last sowing date for your area. This gives you sweet corn throughout the growing season, and planting each variety at least 14 days apart separates the tasseling time for each variety. Staggered planting is an effective method for those with little growing space who want to grow more than one sweet corn variety.
Spacing Corn Types
Other corn types, such as ornamental corn, baby corn and popcorn, must be isolated from all varieties of sweet corn. If these corn types are allowed to cross-pollinate with sweet corn, it makes sweet corn starchy, affecting the corn's flavor. The sweet corn can also contaminate the other corn types. Popcorn pollinated by sweet corn may be sweeter and shriveled. Yellow dominates in sweet corn, so any variety of white corn planted in close proximity to yellow corn will be yellow.
When planting the same corn varieties, the corn is planted in blocks instead of one long row, because this ensures better pollination. Since sweet corn is wind-pollinated, block planting ensures that a good supply of pollen falls on the silks. Sweet corn that is poorly pollinated grows poorly filled ears. Plant sweet corn 8 to 12 inches apart and leave 2 1/2 to 3 feet between rows, planting several short rows.
- The New Sunset Western Garden Book; Kathleen Norris Brenzel, ed.
- Iowa State University Horticulture & Home Pest News: Planting Sweet Corn in the Home Garden
- Purdue University Department of Horiticulture: Growing Sweet Corn
- NA/AbleStock.com/Getty Images