With the exception of plant breeders, we propagate potatoes vegetatively or asexually; potatoes of the same variety are genetically identical to their parents. So, the ‘seed’ that you’ll find to grow potatoes looks like, well, a potato. However, there are some significant differences that separate seed potatoes from the ones you find in the grocery store.
First, most potatoes in the grocery store have been treated with a sprout-inhibitor that prevents the potatoes’ eyes from developing while in storage and on the shelf. Seed potatoes are NEVER treated with sprout inhibitors. This alone can be the difference between growing potatoes successfully or not.
Second, any seed potatoes you buy should be CERTIFIED DISEASE FREE. Potatoes intended to be sold for seed are tested for a panel of diseases before receiving a government-issued ‘disease-free’ certificate. Any seed lots that test positive are not certified and are not sold. Without this assurance, you could unknowingly introduce diseases into your crop and your soil that could persist for many years. So, if you like growing potatoes, don’t risk planting seed from questionable sources because there’s no way of knowing what else you’ll be planting.