Fruit and flower set will be inhibited or deformed. Plants are stunted and older leaves often dark dull green in color. Stems, petioles may turn purple. Plant maturity is often delayed. This condition is rare and usually buffered by pH limitations.
Excess phosphorus can interfere with the availability of copper and zinc.
First apparent on the tips and margins of the leaves. Stem and branches may become weak and easily broken. Excess potassium can aggravate the uptake of magnesium, manganese, zinc and iron. Starting at leaf margin or tip and progressing inward between the veins. Magnesium toxicity is rare and not generally exhibited visibly.