After Harvest

After the grapes are harvested, the vine continues the process of photosynthesis, creating carbohydrate reserves to store in the vine's roots, trunks and cordons until an appropriate level of reserves has been stored.  At that point the chlorophyll in the leaves begins to break down and the leaves change color from green to yellow.  Following the first frost the leaves begin to fall as the vine starts to enter its winter dormancy period.  The stored carbohydrate reserves will be used the following spring to support the initial growth.