The following shoots are thinned:
- absolutely all water shoots ie unwanted shoots arising from the old fibrous wood of the stem (Image 02 - "stem cleaning"), unless they are used for the development of the stem framework ;
- any other infertile shoots without visible inflorescences, which emerge from the pruned fruiting cane (Spur, Rod or Cane / Arched Cane). However, at least one near-stem new shoot must remain at each shoot position for the following winter pruning.
- if there are two or several shoots growing from one bud, the strongest one (with inflorescences) is retained, all others are removed. Many varieties have a tendency to produce several shoots from each shoot position resembling a "hedgehog back," especially when Spur Pruned. This is corrected by shoot thinning.
Shoot thinning is carried out when the new shoots have reached a length of approx. 10 to 30cm, ie at a time in spring when the whole vine is still easily manageable for the layperson. The shoots are either rubbed off by applying some lateral pressure (Image 03), or grasped at their base and pulled off. If necessary, shoot thinning can still be carried out in summer, however, the shoots are then usually cut off with a sharp knife instead of pulled off, due to the beginning lignification.