Popcorn, Zea mays everta, is a unique variety of maize. Unlike sweet corn or field corn, the popcorn kernel has a dense, starchy endosperm completely encased in a thick, hard outer layer called the pericarp or hull. This flinty hull is the structural feature that allows pressure to build inside the kernel when heated, which is the underlying mechanism for popping. The agricultural process of growing, harvesting, and conditioning this specific grain is tailored to preserving this unique internal structure and moisture balance.
Planting the Specialized Seed
The production cycle begins with selecting a planting site that offers warm, well-drained, and fertile soil, as popcorn is a heavy feeder and requires full sun exposure. Planting is timed for late spring or early summer, after the danger of the last frost has passed and the soil temperature has warmed significantly, ideally to at least 60 to 70 degrees Fahrenheit. The seeds are typically sown directly into the field at a depth of one to two inches.
To ensure proper wind pollination, the seeds are planted in blocks or multiple short rows rather than single, long rows. Commercial growers often space the rows between 30 and 36 inches apart, with individual plants thinned to stand approximately 10 to 12 inches apart. This careful spacing establishes a strong, healthy stand that supports the plant through its long growing season.
Field Cultivation and Mid-Season Growth
The crop requires 90 to 120 days to reach maturity and demands consistent care, particularly concerning water and nutrient availability. Popcorn requires about 1.5 to 2 inches of water per week, making irrigation management a significant factor in commercial production, as drought stress can severely reduce kernel quality. The plant has high fertility requirements, especially for nitrogen, which is often applied in split applications throughout the growing season.
Fertilization is frequently scheduled when the plants reach certain growth stages, such as when they are six inches high or beginning to tassel. Weed and pest management strategies employed for popcorn are similar to those used for dent corn, relying on cultural practices and targeted applications. The goal is to maximize the plant’s health, ensuring the ears and kernels develop fully before the natural drying process begins.
Mechanical and Manual Harvesting
Popcorn harvesting differs significantly from other corn types because the kernels must be allowed to dry on the stalk for an extended period. The ears are left in the field until the plant is entirely senesced and the husks are dry and brown, which naturally lowers the kernel’s moisture content. This field drying phase typically brings the moisture level down to a range of 16 to 20 percent, which is suitable for initial harvest.
Large-scale commercial operations use modified combine harvesters to remove the ears from the stalk and shell the kernels. These machines must be operated with care, often with slower cylinder speeds and adjusted concave settings than those used for field corn, to prevent damage to the hard kernels. Manual harvesting may be employed, where the whole ear is picked and then dried further before the kernels are shelled. Harvesting is timed when the moisture content is around 16 to 17 percent to minimize kernel damage during mechanical shelling.
Curing and Processing for Popping
The final curing process defines popcorn production, as it carefully controls the kernel’s internal moisture content after harvest. Kernels harvested at 16 to 20 percent moisture are too wet for optimal popping and must undergo a controlled drying period. This conditioning achieves the precise moisture level required to generate enough internal steam pressure.
For maximum expansion volume, the moisture content must fall within a narrow band of 13.0 to 14.5 percent, with 13.5 percent being the industry standard optimum. If the kernels are too dry (less than 13 percent moisture), steam pressure is insufficient to rupture the hull, leading to unpopped kernels, or “duds.” Conversely, if the kernels retain too much moisture, the hull may rupture prematurely, yielding a small, dense, or chewy popped product. Industrial processors use large storage bins equipped with forced-air ventilation systems to slowly bring the kernels down to this specific moisture content before the grain is shelled, cleaned, and packaged for the consumer.