Minimal Pruning in the Vineyard

In German wine landscapes, one increasingly finds vineyards that have not been pruned in winter and look unusually wild. These are vineyards that are cultivated according to the so-called minimal pruning principle. With this form of cultivation, one simply drives through the rows of vines with the foliage trimmer in winter to shorten the shoots a little, instead of the traditional method of manually pruning the vine back to one or two canes and removing the remaining vine wood from the wire frame.

Minimal pruning is closer to the original growth behaviour of the vine and also saves considerable cost and time. In conventional grape production, almost a quarter of the working time is spent on classic pruning. Expressed in figures, this means: Instead of a grower spending around 90 hours per hectare on pruning and subsequent bending of the shoots, they only need about six hours with minimal pruning. Moreover, pruning must be carried out by qualified personnel, which is another argument for producers to switch to minimal pruning in view of the general shortage of skilled workers.

If this system is practised with the new grape varieties which hardly need any plant protection (PiWis), about two-thirds of the resources can be saved, in addition to further costs and time.

In addition, since minimal pruning does not cause large pruning wounds, it prevents wood-destroying fungi from entering the vine, which leads to vine death from the ever-spreading Esca disease.

The risk of yield losses caused by extreme weather events such as sunburn and hailstorms, which have increased in recent years due to climate change, can also be reduced by minimal pruning because the grapes are better protected by the thicker foliage.

As a rule, the grapes ripen later in minimal pruning systems, which is another advantage in hot years, an increasingly frequent phenomenon of climate change. Otherwise, with the heat causing earlier ripening, the grapes would have to be harvested in August to prevent them from becoming too sweet and therefore, the wines from becoming too strong later on. With later ripening, the grapes benefit from the cool nights and ideally sunny autumn days, which promotes aroma formation.

In cool and rainy years, however, later grape ripening can also be a disadvantage. In that case, it is especially important to reduce the yield early. This is generally recommended with this form of minimal pruning because the number of grapes per vine is significantly higher than with conventional pruning.

In addition, it must be taken into account that the vines have a higher demand for water when they are more heavily hung with grapes and have more leaves. Winegrowers can counteract this by extending the distance between the rows of vines from the usual two metres to three metres when planting new vines, in order to give the vine roots more space to absorb water. If a narrower foliage wall is used for minimal pruning in classical trellis training, row spacing of two metres is sufficient.

The change from conventional pruning to minimal pruning initially means a big change for the plants. After a few years, however, a natural balance is achieved. Wine growers with many years of minimal pruning experience also speak of generally more robust vines.