Prune the grape vines back severely by cutting off most of the vine except for the main stem and a few new buds. Cutting the grape vines before moving reduces the stress on the root system during the transplanting process.
Water the grape vines well one day before the selected transplant date.
Dig up the mature grape vine with as much of the root system as possible. Try to keep at least 1 foot of the roots or more. Place the roots in a container of water while you dig the new hole.
Dig a hole the same depth as the grape vine's root system, and wide enough to place all of the roots into the ground so they spread out naturally. Loosen the soil around the planting hole to assist the spreading of the roots as they grow.
Place the grape vine in the center of the hole. Fill the hole with the removed soil and pack the soil around the roots to remove any air pockets. Continue adding soil until the hole is filled, and then flood the area with water to settle the grape vines in place.
Water the transplanted grape vine as needed when the soil dries a few inches down throughout the first season. Cover the area around the grape vine with 4 to 6 inches of mulch to prevent weeds and to hold moisture in the soil.