A low-cost method for increasing the number of grape vines in a vineyard is by propagating new plants by rooting stem cuttings. This allows you to select healthy vines and propagate the number needed for planting. Grape vine propagation has best results when hardwood cuttings are taken during the dormant season. Hardwood cuttings are sections of current-year growth that has become woody and mature. Rooting cuttings will ensure the new plant is genetically identical to the vine it was taken from.
Take hardwood grape vine cuttings once the plant goes dormant in fall. Cut a section of 1-year-old growth that contains two to four bud nodes. Tie the cuttings into bundles and wrap them in burlap for winter storage. Place the cuttings in a dry location with a temperature of approximately 32 degrees F.
Remove the cuttings from storage in late winter. Prepare rooting medium by mixing equal portions of peat moss, perlite and course sand. Moisten the medium with water and fill it into a rooting tray.
Dip the cut end of the stem sections into an indolebutyric acid rooting hormone. Stick the cutting into the rooting tray to a depth of one-third to one-half the length of the stem. Firm the medium around the cutting to hold it in place. Space the cuttings 2 inches apart in the rooting tray.
Place the cuttings on germination heating pad in a greenhouse environment with a daytime temperature of 65 to 70 degrees F and nighttime temperature of 60 degrees F. Set up a misting system to spray the cuttings every 10 minutes during the daylight hours.
Transplant the cuttings to 1-gallon growing containers once the roots reach a length of 1 inch. Root development will take approximately four to six weeks. Fill the growing containers with a medium that is equal portions peat moss, course sand and sterile soil.
Establish the transplanted cuttings in a greenhouse environment for the first growing season. Plant the cuttings outdoors the following spring, once there is no longer a risk of frost.