Young vines obtained from the nursery are often planted in the field without any pre-preparation.
Vines must be soaked in water for at least six hours to restore water status and prevent dessication after planting. It goes without saying that the correct cultivation practices must also be followed during planting. After soaking, hot water treatment may be applied to eliminate bacterial and fungal diseases, kill insects, as well as to stimulate root and shoot growth. Vines must preferably be planted within a day of hot water treatment.
Vines must then be cut back to two buds on a straight shoot. The rest of the shoots are cut back against the trunk. Since there is a risk of damaging these buds during planting, some producers prefer to cut back only once the vines have been planted. In many instances these vines are cut back much too late or never. The result is that a large number of buds burst and many weak shoots form, (Fig. a) making it difficult to find a shoot with sufficient vigour to be used as a trunk (Fig b). Initial vegetative growth and root development of a young vine are dependent on the reserve nutrients of the vine. From a hothouse study, it was apparent that up to 60% of the starch reserves are used during the first three to four weeks after planting to support new growth. After four weeks stored reserves are no longer used, with the result that from then on vines are dependent on their own carbohydrate production. If the vines are therefore cut back too late, a large amount of reserves are used unnecessarily. Further development of young vines may consequently be hampered by a shortage of reserves, as well as insufficient carbohydrate production.
If the vines are cut back before planting or directly thereafter, all available reserves may be used for initial vegetative growth and root development, which will result in stronger shoot growth (Fig. c). Under favourable environmental conditions and if vines are prepared, planted and irrigated correctly, development will be stimulated.