b'The uptake of potassium is particularly high during vegetative growth. It is absorbed by the plant both actively and passively. Passive absorption means that potassium is also absorbed by the evaporation of the leaves.Deficiency symptomsPotassium deficiency is manifested by the brown discolouration of the leaf margins and yellowing between the veins of older leaves. Root growth is delayed and the stems turn brown. In the fruit, potassium promotes hardness, colour and taste. The plants are less resistant to frost and more sensitive to various diseases because the cell wall is more easily accessible to fungi. If there are shortages, the potassium moves from the plant cell in the old leaf to the young leaves.Lack of potassiumExcess symptomsAn excess of potassium is also not good. During the absorption it competes with calcium, ammonium and magnesium, so that these 3 minerals are absorbed less and can cause deficiency symptoms.112'