Martino, greefig has it right. Wrap the entire scion (wedge graft, tongue and groove, etc) in parafilm, except for the actual graft point. This is to keep the moisture in the scion. Use green nursery tape, or other suitable product, to tighten the graft point to increase cambium contact and seal the graft point.






Grafting, as Martino has said, has many reasons. T-budding or chip budding only uses one bud, so you get more plants from the same amount of scion. You get a productive plant faster because you already have an established root system. Multiple varieties on one tree. For plants where you have developed rootstocks, you can put the plant variety (fruit, flowers, etc.) on the roots that work in yo9ur soil type.