Deficiency Symptoms Which Appear on Oldest Leaves First

The following deficiencies appear on older leaves first as the elements involved are very mobile within a plant. If a nutrient on this list isn’t available in sufficient quantities to satisfy the entire plant’s needs, it is removed from lower, older leaves to sustain new growth at the top of a plant.

Nitrogen (N): deficiency marked by gradually yellowing leaves, small leaves, and stunted growth.

Phosphorous (P): deficiency marked by stunted growth and reduced branching. Small leaves and small numbers of new leaves. Older leaves darken in colour, becoming dark green, blue-green or even purple.

Potassium (K): deficiency marked by stunted growth and yellowing leaf tips and edges. This yellowing progresses towards centre of leaf. Leaf edges look ’scorched’ as they brown and die. Plant wilts easily under water stress.

Magnesium (Mg): deficiency marked by yellowing between leaf veins (interveinal chlorosis), followed by dead, brown patches within these regions in extreme cases.

Molybdenum (Mo): deficiency marked by strong resemblance to a nitrogen one, with stunted growth and chlorosis. Unlike a nitrogen deficiency, where chlorosis is gradual and uniform across a leaf, a molybdenum-induced chlorosis shows as a rapid death of tissue on the leaf edges. This ‘burn’ can resemble a nitrogen toxicity.

Deficiency Symptoms Which Appear on Newest Leaves First

The following deficiencies appear on newer leaves first as the elements involved are not very mobile within a plant. If a nutrient on this list isn’t available in sufficient quantities to satisfy the entire plant’s needs, new growth at the top of a plant cannot be sustained.

Sulfur (S): deficiency marked by top-most leaves changing from light-green to almost yellow in colour. Internode lengths decrease as growth decreases.

Calcium (Ca): deficiency marked by new leaf tips and edges yellowing and then dying. Growing root tips are especially affected, as are fruits and storage tissues.

Iron (Fe): deficiency marked by yellowing between leaf veins (interveinal chlorosis). New leaves show a very noticeable network of dark green veins against a light green or even yellow background. Very young leaves may be completely white.

Manganese (Mn): deficiency marked by yellowing between leaf veins (interveinal chlorosis) which strongly resembles a magnesium or iron deficiency. (If on oldest leaves, it is a magnesium deficiency.) On newer leaves it is harder to diagnose whether an iron or manganese deficiency, but discolouration is more uniform across a leaf for iron while more spotted (and sometimes marked with brown, dead patches) for manganese.

Zinc (Zn): deficiency marked by stunted growth, small leaves, and shortened internodes, creating a distinctive ‘rosette’ or whorled appearance at the top of a growing shoot. Leaves may also be more narrow than normal, and with wavy edges.

Copper (Cu): deficiency marked by a compact appearance due to shortened internodes. Leaves may be very small, dull in colour, and the edges first lighten then die.

Boron (B): deficiency marked by brittle stems, overly-thick new leaves, and short stubby roots with few root hairs. Internode lengths decrease and the plant takes on a bushy ‘rosette’ appearance at the ends of new growth.