Grafting is a gardening and orchard management technique for growing fruiting and flowering trees of one varietal on the hardier and stronger performing root stock of another varietal. Grafting involves placing scion branches cut from the new tree top into the trunk of the rootstock tree, securing them and keeping them moist until the two raw wood cuts grow together into a new tree hardened at the union.
Preparation & Storing of Scions
Scion wood should be harvested in the winter or early spring from healthy shoots grown the previous year. Cut scions with clean sharp secateurs or a garden knife, making sure that you have at least three buds or leaf axils on each length of scion wood. If you don't plan to graft the scions at that moment, immediately wrap the scion wood in damp sphagnum moss or damp paper toweling and place into a resealable plastic bag and store in the lower third of the refrigerator near the back where it remains the coldest. Do not, however, store the scion wood in a fridge where fruits or vegetables are stored, as their ethylene gas can cause the scion buds to die and render the scion wood unusable. Check on paper toweling or moss every few weeks to make sure that it has not dried out. If it does not feel moist to the touch and there is no condensation at all in the bag, re-dampen with a few sprinkles of clean water and reseal the bag.
Securing the Graft
While there are dozens of techniques for grafting that are chosen for any number of reasons including tree age and varietal, personal preference and past success, securing the graft is always of paramount importance and is where success is either made or lost. Whatever grafting method you have chosen always ensure that the raw cut wood or cambia surfaces of both the scion and root stock wood are in immediate snug contact and will not pop out or loosen over time. This snugging is created by careful cutting of the scion and rootstock to fit together and aided by the use of several grafting tools of the trade including biodegradable rubber banding called grafting bands or the use of biodegradable grafting tape. Each will disintegrate over time to prevent girdling of the tree and graft site but remain snug in the early stages to ensure a strong connection until the union has healed.
Maintaining Moisture at the Graft Union
After securing the graft, the next most important thing to do its to prevent the graft union site from drying out which will make the graft fail. To seal the graft area you can use melted grafting wax or grafting paint, which is a viscous sealant, by painting either of them on all of the exposed graft surfaces. An alternative is to place plastic bags secured with rubber bands around the grafts to preserve moisture loss. When the scions begin to sprout green growth, you can prune away all but the most vigorous one or two, and these will be the main trunk or branches of the newly grafted tree.