Key to visually diagnosing nutritional deficiencies.
Visual Symptom
Older or lower leaves of plant mostly affected; affects localized or generalized
1. Effects mostly generalized over whole plant; more or less
Nutrient
drying or firing of lower leaves; plant light or dark green.
A. Plant light green: lower leaves yellow. Drying to light
brown color; stalks short and slender if element is deficient Nitrogen
in later stages of growth. (mobile)
B. Plant dark green: often developing red and purple colors;
stalks short and slender if element is deficient in later Phosphorus
stages of growth. (mobile)
2. Effects mostly localized; mottling or chlorosis with or
without spots of dead tissue on lower leaves.
A. Mottled or chlorotic leaves; typically may redden, as Magnesium
with cotton; sometimes with dead spots; margins turned or (mobile)
cupped upward; stalks slender.
B. Mottled or chlorotic leaves with large or small spots of
dead tissue.
1. Spots of dead tissue small, usually at tips between Potassium
veins, more marked at margins of leaves: stalks slender. (mobile)
2. Spots generalized, rapidly enlarging, generally
involving areas between veins and eventually involving Zinc
secondary and even primary veins; leaved thick; stalks (intermediate)
with shortened internodes.
Newer or bud leaves affected; symptoms localized
1. Terminal bud dies, following appearance
of distortions at tips or bases of young leaves.
A. Young leaves of terminal bud at first typically hooked, finally Calcium
dying back at tips and margins, so that later growth is (immobile)
characterized by a cut-out appearance at these points; stalk
finally dies at terminal bud.
B. Young leaves of terminal bud becoming light green at bases, Boron
with final break-down here: in later growth, leaves become (immobile)
twisted; stalk finally dies back at terminal bud.
2. Terminal bud commonly stays alive; wilting or chlorosis of younger or bud leaves with or without spots of dead tissue; veins light or dark green.
A. Young leaves permanently wilted (wither tip effect) without Copper
spotting or marked chlorosis; twig or stalk just below tip and (intermediate)
seedhead often unable to stand erect in later stages when
shortage is acute.
3. Young leaves not wilted; chlorosis present with or without spots of dead tissue scattered over leaf.
A. Spots of dead tissue scattered over leaf the leaf; smallest Manganese
veins tend remain green producing a checkered or (intermediate)
reticultaing effect.
B. Dead spots not commonly present; chlorosis may or may not involve veins; making them light or dark green in color.
1. Young leaves with veins and tissue between veins Sulfur
light green in color. (intermediate)
2. Young leaves chlorotic; principal veins Iron
typically green; stalks short and slender (immobile)
Source: McMurray, 1950,
Diagnostic Techniques for Soils and Crops. American Potash Institute.
Few key thoughts from me:
1. If the symptoms appear on older leaves or portions of the plant, the nutrient is mobile inside the plant. If the deficiency appears on new growth or terminal buds, the nutrient is immobile.
2. Iron deficiencies are common in Utah.
3. If your tomatoes are purpling it is often a phosphorus deficiency. Blossom end rot on tomatoes is caused by poor watering or a calcium deficiency.
