Potatoes are one of the world’s most significant food crops, a starchy tuber that serves as a staple in diets across the globe. While all potatoes are botanically the same species, Solanum tuberosum, they are categorized into two distinct groups based on their intended use. The fundamental difference lies in their purpose: regular potatoes are grown and harvested for consumption, while seed potatoes are cultivated specifically to be planted and produce the next generation of crops. This distinction results in vastly different handling, treatment, and quality control standards for each type.
The Primary Distinction: Disease Control and Certification
The most significant difference between the two types is the rigorous, multi-year certification process applied to seed potatoes. Potatoes reproduce asexually, meaning that any virus or bacterial infection present in the parent tuber is passed directly to the next generation. Over time, this leads to a buildup of pathogens, a phenomenon known as varietal degeneration, which can severely reduce crop yield.
Certified seed potatoes are produced under strict government-regulated programs to ensure the lowest possible disease load, confirmed through field inspections and laboratory tests. Common and destructive pathogens, such as Potato Virus Y (PVY) and Potato Leafroll Virus (PLRV), are monitored because they are tuberborne and can reduce yields by up to 80%. These programs establish specific tolerance levels for various diseases, and seed lots exceeding these limits are not certified for planting. Buying certified seed guarantees the gardener a high-quality tuber with minimal risk of introducing harmful diseases into their soil.
Physical Characteristics and Post-Harvest Treatment
The physical state and post-harvest chemical treatment of the two potato types further solidify their separation. Regular potatoes destined for the grocery store are routinely treated with sprout inhibitors to maintain their appearance and quality during long-term storage and transport. These treatments, including chemicals like chlorpropham (CIPC) or maleic hydrazide (MH), prevent the potato’s “eyes” from sprouting. Since CIPC disrupts the cell division necessary for sprout growth, a treated potato will not grow successfully when planted.
Seed potatoes, conversely, are never treated with sprout-inhibiting chemicals, as their function is to germinate and grow. They are instead stored in carefully controlled environments with specific temperatures and humidity levels to encourage a healthy pre-planting sprout. Seed potatoes are also typically smaller than their table-stock counterparts, a size selected for optimal performance when planted whole or cut into a few pieces. This smaller size ensures that the seed piece has enough stored energy for the initial growth of the plant.
Practical Use and Implications for Planting Viability
The practical implication for gardeners is that planting a regular potato from the grocery store is highly inadvisable. The presence of sprout inhibitors makes successful sprouting and subsequent crop production unlikely. Even if a grocery store potato manages to sprout, it carries the significant risk of introducing latent viruses or bacteria into the garden soil, which can accumulate and affect the health of future potato crops for years.
A gardener should always purchase certified seed potatoes to ensure a reliable and abundant harvest. This investment guarantees that the potato has been tested for diseases and stored correctly to maintain its viability for planting. The certified seed label represents a quality assurance standard that table potatoes simply do not require.