The potato (Solanum tuberosum) is a starchy tuber that originated in the Andes mountains of South America. Technically an underground stem rather than a root, it stores energy for the plant. Potato cultivation is highly efficient, producing more food per unit of water and land than most major grain crops. This process relies on a form of cloning, ensuring a consistent, high-yielding food source consumed globally.
Preparing the Seed and Soil
Potato production uses vegetative propagation rather than true botanical seeds, relying on specialized tubers called “seed potatoes.” These are selected from certified, disease-free stock, ensuring the new plants are genetic clones of the parent variety. Growers often cut larger seed potatoes into smaller pieces, making sure each section contains at least one or two “eyes,” the dormant buds from which the new plant will sprout.
Before planting, the cut pieces are allowed to sit for a couple of days so a protective callus layer can form over the surface. This healing process prevents the seed piece from rotting in the moist soil. The soil must be loose, well-drained, and rich in organic matter to allow for optimal tuber expansion and aeration. Planting occurs in early spring when the soil temperature reaches a minimum of 45 degrees Fahrenheit.
Cultivating the Growing Potato
Once the soil is prepared, seed pieces are planted relatively deep, often 6 to 8 inches below the surface, and spaced about a foot apart within the row. A critical step in cultivation is “hilling,” which involves repeatedly mounding soil or organic material around the base of the growing plant. This process begins when young shoots are approximately 6 to 8 inches tall and is repeated as the plant grows.
Hilling serves two purposes: it provides structural support and ensures the developing tubers remain completely shielded from light. The potato plant produces new tubers along the buried portion of the stem. By continually adding soil, the grower encourages the formation of more tubers higher up the stem, increasing the overall yield of the crop.
Crucially, the absence of light prevents a process called greening, which is the accumulation of chlorophyll just beneath the tuber’s skin. Greening is an indicator of the simultaneous production of glycoalkaloids, primarily solanine, a naturally occurring compound that is toxic in high concentrations. Hilling acts as a physical barrier to keep the tubers in darkness, preventing the development of solanine, which causes a bitter taste. The developing plants require a consistent supply of water throughout the growing season, especially during the period of tuber formation, to maintain steady growth and maximize the final harvest size.
Harvesting and Post-Harvest Curing
The signal for the end of the growth cycle is the natural senescence, or die-down, of the potato plant’s vines and leaves, which turn yellow and brown. For commercial operations, the vines are sometimes mechanically or chemically removed (dehaulming) a couple of weeks before harvest. This intentional removal allows the potato skin to fully “set” or toughen, which reduces the chance of skinning or bruising during the digging process.
Harvesting is typically done using specialized equipment, such as potato diggers or harvesters, that lift the tubers from the soil. Minimizing mechanical damage is paramount because cuts or bruises create entry points for disease-causing pathogens that can ruin the stored crop. After being dug up, potatoes are not ready for long-term storage and must first undergo a specialized process called curing.
Curing involves holding newly harvested potatoes in a warm, humid environment for one to two weeks, typically at 50 to 60 degrees Fahrenheit and 85 to 95 percent relative humidity. This controlled environment allows minor harvest wounds to quickly heal and form a protective cork layer, while also thickening the skin. Successful curing enables the tubers to be stored for extended periods without significant water loss or succumbing to rot.