Consult manufacturer's label for complete information on rates and timing. As the soil pH rises over 7, or in heavily limed soils, iron becomes unavailable to plants. Occasionally, a few plants may exhibit iron-deficiency symptoms. These are often located near the site of previous lime or building plaster storage where the soil pH is abnormally high. Iron deficiency may also occur in isolated parts of the field or on a few individual plants.
Iron deficiency causes interveinal chlorosis of new leaves.
As the condition becomes more severe, the whole leaf becomes pale yellow. Quite often only one side or one branch of the plant is affected. Currently there is no accredited soil test for iron in Ontario. Confirm a suspected deficiency with a petiole analysis . Generally, soil applications of inorganic iron sources are not effective in supplying iron to the crop.