Many people mistakenly believe the edible part of a corn plant, the ear, grows beneath the soil like a potato or carrot. This confusion often arises because staple food crops, such as root vegetables and tubers, are harvested from underground. Corn is botanically classified as a grain, and its entire reproductive structure develops fully above the ground. The plant’s architecture is a tall, single stem that supports the reproductive organs that produce the kernels we eat.
The Edible Part: Where Corn Ears Develop
The edible ear of corn develops high up on the main stalk, separate from the subterranean components of the plant. This ear is the female reproductive structure, originating from an axillary bud at a node along the stalk, typically around the middle of the plant’s height. It consists of a central cob upon which the kernels are arranged in paired rows, all encased and protected by tightly wrapped, modified leaves called husks.
Each potential kernel on the cob is attached to a single strand of corn silk, a specialized, hair-like structure that emerges from the tip of the husk. Kernels are technically the seeds of the plant. They develop after a pollen grain lands on an exposed silk and travels down the tube to fertilize the ovule.
The Root System: What Stays Underground
While the harvestable product is above ground, the corn plant maintains a complex and expansive root system that remains entirely within the soil. This root network serves two primary functions: absorbing water and nutrients and providing structural support for the tall, heavy stalk. A corn plant initially develops a small seminal root system from the seed, but this is quickly overtaken by the more extensive nodal root system.
The nodal roots are also known as the crown roots, and they emerge in sets from the nodes of the stalk that are below the soil surface. These roots can extend several feet deep and wide, forming a dense fibrous network that anchors the plant against wind and rain. Additionally, some roots, often called “brace roots,” develop from the lowest nodes above the soil but then grow downward to penetrate the ground, providing extra stability for the mature plant.
From Seed to Harvest: Key Growth Stages
The life of a corn plant is divided into distinct vegetative (V) and reproductive (R) growth phases, each contributing to the development of the above- and below-ground structures. The initial vegetative stages focus on the development of the stalk, leaves, and the dominant nodal root system. By the time the plant reaches the V6 stage, the growing point, which was once protected beneath the soil, moves up above the ground, making the plant more vulnerable to damage.
The reproductive phase begins with the emergence of the tassel, the male flower, at the very top of the stalk. A few days later, the silks emerge from the developing ears lower down on the stalk, marking the R1 or silking stage. Pollination occurs when pollen from the tassel falls onto the receptive silks, initiating the fertilization of the ovules and the subsequent development of the kernels on the cob.