When farmers plant potatoes, they typically thin the crop early in the season by pulling some juveniles to allow those remaining in the soil room to grow. These immature potatoes, of whatever kind the farmer chose to plant, are called new potatoes; the term refers to their age, not to their variety. They are round or oblong in shape and range from the size of a walnut to the size of a ping pong ball.
Harbingers of spring, new potatoes appear in farmers markets in April and continue through July. Since they are harvested so early, they have thin, wispy skins that may feather and peel off in some places. Because their skin is so thin,they don’t need to be peeled before cooking, and they keep their shape when subjected to heat. Their texture is crisp and waxy, and they are sweeter than their adult siblings\s because their sugar has not yet converted to starch.
Fingerlings, on the other hand, are a specific variety of potato that at maturity are about the size of a knobby finger. They arrive in the markets later than new potatoes and, like new potatoes, fingerlings are thin skinned and do not need to be peeled before cooking. They also hold their shape well while cooking, but they taste more like regular potatoes and lack the creamy delicacy of new potatoes. These thin skinned taters are more perishable than regular spuds and should be eaten within a few days of purchase.