There are three main types of plate boundary: divergent, convergent and transform. Plates move away from one another at divergent boundaries. This happens at mid-ocean ridges. Plates move towards one another at convergent boundaries; one plate is forced below another in a process called subduction.
The skin of a Concord grape is typically dark blue or purple, and often is covered with a lighter-coloured epicuticular wax bloom that can be rubbed off. It is a slip-skin variety, meaning that the skin is easily separated from the fruit. Concord grapes have large seeds and are highly aromatic.
The color of the vine also indicates when to harvest Concord grapes. Throughout the growing season, the vine and stems are a light to medium green. When the vine and stems begin to turn to a light then medium brown, it means the grapes are ripening and ready to harvest.