Symptoms
Youngest leaves show a faint yellowgreen tint.
Reasons
Iron deficiency
Iron is the micronutrient needed in greatest quantities within brassicas, but deficiencies are rarely seen.
Lack of Fe is most frequent on light, alkaline and calcareous soils with low organic matter. However, soils with peat substrates have a naturally low Fe content.
High P fertilization may also induce Fe deficiency.