Lack of Magnesium (Mg)
Magnesium is an indispensable element for plants. Magnesium deficiency is evident in the central part of the plant or in the low leaves. It is an element in the green pigment of the leaf of essential importance for photosynthesis. When it is missing, the leaves turn yellow or lose their color completely with the veins remaining dark green. The low leaves may show yellow spots, folding of the margins and consequent fall. Magnesium plays an important role in various metabolic processes and the deficient plant can turn yellow in a few weeks and, if it gets worse, end up turning white.
Some reasons for Magnesium deficiency:
a wet, cold and/or acidic environment in the root area
a high potassium, ammonium and/or calcium content (e.g. a lot of limescale in tap water or clayey soil) compared to the magnesium content
a limited root system and a heavy load on the plant
high EC value in the substrate, reduced evaporation.
Yellow, cloud-like spots between leaf nerves.
Early loss of older leaves
Upward folding of the leaf margins
Rarely is an excess of Magnesium found that is not easily identifiable even with careful monitoring.