Non-metallic trace element (B), which occurs in small quantities in all soils and plants. This nutrient is very important for the growth of the vine, which needs it to transport sugar. Only small quantities are needed, too large quantities also cause damage. Young vines in particular can die after boron over-fertilisation. Excess boron is expressed by yellowish or reddish discoloration of the leaves from the edge of the leaves, as well as punctiform death symptoms. With slight deficiency the leaves are light and dark green marbled, with stronger deficiency the younger leaves shine, change colour from the edge, become wavy and die off. The leaves are partly asymmetrical (crooked) and somewhat torn. If there is a severe deficiency, tendrils and shoot tips die off, lateral and stinging shoots then grow more strongly and so-called broom growth and chlorosis occurs. With boron surplus as well as with boron deficiency, germination and fruit set are impaired and the fruits trickle away. This in turn leads to chicken disease or small berries. Boron deficiency occurs particularly in dry conditions. Preventive measures are therefore advisable with regard to water storage capacity. Furthermore, a deficiency can be eliminated by boron salt fertilization or by leaf pollination.