Nutrient deficiency symptoms Nitrogen Phosphorus Potassium Magnesium Iron Manganese Molybdenum

Nitrogen deficiency is typically a yellowing of leaves particularly the older/lower ones as shown top left; compare with healthy leaves bottom left. It can be confused with other deficiencies e.g. magnesium deficiency (see bottom right) where the leaf shows a yellowing between the dark green veins.

Phosphorus deficiency shows as a purple colouring of the leaf. Often the veins of the leaf turn purple. In this example the purple colouring is central to the leaf. It can often be confused as cold damage; but the damage is away from the margin of the leaf.

Potassium deficiency typically appears as a marginal yellowing/browning/purpling of the deciduous leaf margin; this ‘scorching’ starts at the tip of monocotyledonous leaves. Eventually the whole of the leaf is affected by the loss of green and with increasing distortion.

Magnesium is very soluble within the plant. Older leaves suffer from magnesium deficiency as the plant removes magnesium from the older leaves to support the younger leaves. The veins remain dark green and there is yellowing in between the veins.

Iron deficiency only appears on the younger leaves because it is immobile (insoluble) in the plant. Continued deficiency leads to the green of the leaf veins gradually being bleached progressively from the leaf tip end.

The top leaf is showing no deficiencies and is the normal dark green colour. The bottom leaf has started to lose the dark green colour and there is evidence of purple spotting as shown by the red arrow on the leaf.

Molybdedum deficiency symptoms are uncommon, but often starts with a breakdown of the leaf cells – see purple spots on leaf shown below (indicated by red arrow). Typically the leaf margin gradually deteriorates until there is an overall yellowing/browning of the leaf except the leaf tip. In other plants there is a severe reduction of the leaf blade e.g. ‘whiptail’ in cauliflowers.