The popcorn plant looks like a sweet corn or field corn plant, perhaps a little smaller in stature. Popcorn seed is a whole grain comprised of three components: the germ, endosperm and pericarp (or hull). The hull allows pressure from the heated water inside to build up and eventually burst open, creating the dry, white puffy treat. Popcorn seed needs between 13 to 14 percent moisture content to successfully pop, according to America's Popcorn Board.
Popcorn is a member of the grass family, Poaceae. It's botanically known as Zea mays var. everta and is genetically very close to other types of corns, like sweet, ornamental or field (grain) corn.
All corns hail from temperate or tropical parts of North and South America. The oldest ears of popcorn ever discovered were found in west central New Mexico in 1948 and 1950 at the archaeological site known as "Bat Cave." The popcorn dated to be nearly 4,000 years, old according to the Popcorn Board's website. Popcorn was used by Aztecs and Peruvian Indians in the 16th century as documented by Spaniards, including Cortes.
The introduction of the moldboard plow in the middle of the 19th century increased production of all types of corn (maize) in the United States. From the 1890s to the 1930s, popcorn was an extremely popular novelty food. Served with the first motion pictures, popcorn consumption in the country dropped off with the introduction of the television. During World War II, the rationing of sugar lead to a diminished supply of candy, but popcorn consumption increased appropriately three-fold. Today, the average American eats about 54 quarts of popped popcorn, about 70 percent of that in their own homes, reports the American Popcorn Board. Major popcorn-producing states include Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Missouri, Nebraska and Ohio.
While most may see a jar of popcorn in the supermarket snack aisle as popping kernels, they essentially are the seeds that germinate and develop into popcorn plants. The seed is small and has tapering points, unlike sweet corn. Popcorn seeds range in color from nearly white or pale beige to golden yellow, depending on variety. It has a thick hull, setting it apart from other types of corns, which allows it to expand and pop when heated. Some describe popcorn seeds as resembling plump rice grains or pearl-shaped.
Growing popcorn follows the same general guidelines for both sweet and grain corn. Seeds are sown about 1-inch deep in a moist, well-draining, fertile soil in full sun exposures when there is no danger of frost at the beginning of the growing season. Popcorn seeds take longer to germinate, though. Purdue University mentions that slightly less fertile soils or application of fertilizers are required with popcorn since the plants yield less kernels per plant than modern sweet or field corn varieties. The plants need 18 to 24 inches of rainfall or irrigation across the growing season.
Also in comparison to other corns, popcorn plants grow at a slower rate but still need a long, warm growing season since the ears must fully ripen and dry on the plant before harvesting. In comparison, sweet corn is harvested when it is tender and immature in the ears.