The Cleft Graft
Pictures is showing the principles on how to cut & manage the Scion. The old vine on the pictures is no good, there is winter damage!!! If you make the graft 3 " above ground, it is important to cover the graft with dark soil, this will heat up the grafting area during spring. Grafting zone needs min 20 C to make callus. Scion can be with 2-3 eyes for better yield. . If the stump is big use 2 scions. The cambium (green layer) must grow together side-by-side. Best results with cleft grafts are usually obtained by late grafting; that is, from early April to m¡d-April.
Attention: take care of drying out the Scion !!! Read more on University of Florida's page under: PROPAGATION AND PLANTING
More details on grafting on grapevine: The University of California this is a great page, just missing some pictures....
Whip grafting on young vine: Texas Agricultural Extension Service
1 Scion is cut so it is thinner on the "inside"
2 Scion is cut so it is thicker on the "outside"
5 Open the cleft slightly with a grafting tool or screw driver
6 Insert the scion, or insert a scion on each side, with the inner bark of stock and scion in contact
8 NO GOOD, there must be 100% contact. Add some tape (tight) for better contact.
The pressure of a large stump may hold a scion securely
Details on a "stripped" old (dead) vine:
The wedge cut should be inserted carefully into the cleft so that the cambium on its thickest edge and that of the stump match
Secure grafting with tape and grafting compound / wax. Check the compound or wax after a week or 2 !!!
Chance for Success is depending on 110% airtight sealing !!!
Søren Larsen Truntehus Denmark