HVG Germany: Hopfen



The Hop-growing Year: Training the hops


Stripping the lower bines and training the shoots

In the spring 40-60 shoots grow from each hill from the end of April onwards. Only 4-6 shoots are required for normal development. The rest are cut off. The retained shoots are "trained", i.e. they are twisted around the training wires in a clockwise direction. This helps the hop shoots to continue growing upwards.
Circular cultivators have proved successful in facilitating the stripping. The cultivators should be operated as flat as possible to avoid damage to the root systems. Trials have shown that more than two shoots per training wire brought no additional yield but the susceptibility for wilt disease was higher due to the more dense foliage.
As the shoots are occasionally dislodged by the wind during growth some shoots have to be "retrained" several times later on. New shoots grow from the rootstock again and again. These are not required, in fact they are a breeding ground for pests and diseases and diminish the growth force of the hill. Therefore they must be removed in several operations. These late shoots are removed manually or with the sprayer. At the same time nitrogen fertilizer is dissolved and sprayed onto those shoots which are to be killed off. Consequently this chemical (ammonia sulphate) simultaneously kills off the late shoots and acts as a fertilizer.

Removing the lower shoots and defoliating reduces the extent of infection

New shoots grow from the hop plants again and again. A good micro-climate for pests and diseases develops on these bottom shoots and the laterals near the ground. The bottom shoots are already to a certain extent infected with downy mildew (spikes) and mildew.
It is therefore important to remove the lower shoots and lower laterals to reduce the spread of infection with powdery and downy mildew and red spider mite and this can save many a spraying treatment.
In the past few years mechanical defoliating apparatus has been developed. When being used it is important to observe the optimum time and optimum setting.
When the trained bines have reached a height of 1-2 metres mixtures containing nitrogen can be used to remove the surplus lower shoot.