Signs of Nutrient Deficiencies

Boron (trace element)	Death of stem and/or root apical meristem, leaves twisted, young tissue are most affected; dead shoot tips, new side shoots also die
Calcium	Death of shoot and root tips; young leaves and shoots are most effected;  Damage and die-off of growing points; Yellowish leaf edges
Cobalt (trace element)	Stunted growth; used for nitrogen fixation, same as nitrogen deficiency signs
Copper (trace element)	Young leaves dark green, twisted, wilted, tip remains alive; dead leaf tips & withered edges
Iron	Chlorosis of tissue between veins; stems short and slender; young leaves are more affected; leaves turning yellow
Magnesium (trace element)	Chlorosis of leaves; older leaves are more affected; Yellow spots on leaves
Manganese	Chlorosis of young leaves, with smallest veins remaining green, necrosis between veins; dead yellowish tissue between leaf nerves
Molybdenum (trace element)	Chlorosis, twisting, death of young leaves; yellow spots between leaf nerves, then brownish areas along edges
Nickel (trace element)	Lack of germination or seed formation, required for iron absorption
Nitrogen	Chlorosis of leaves; slow growth; small, stunted plants with large root systems; leaves turning yellow
Phosphorous	Chlorosis of leaves; slow growth; small, stunted plants with large root systems; Premature leaf fall-off
Potassium	Chlorosis, necrosis, weak stems and roots; older leaves are more affected; Yellow areas and withering of leaf edges & tips, Pinholes
Sulfur	Chlorosis of leaves; slow growth; small, stunted plants with large root systems; leaves turning yellow
Zinc (trace element)	Reduced leaf size, shortened internodes, Chlorosis, spotted leaves, older leaves are most affected; yellow spots between leaf nerves, then brownish areas along edges.

                                                 Definitions:

Chlorosis - The yellowing or whitening of normally green plant tissue caused by a decreased amount of chlorophyll, usually as a result of disease or nutrient deficiency.

Necrosis - The death of plant tissue in small patches or zones, in response to disease, insect/fish attack, or injury.

Apical Meristem – New cells at the tip of a plant shoot or root that causes the shoot or root to increase in length.

Internodes – The portion of the stem between where the leaves attach.

Kelly 

"Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so."  ~ Douglas Adams