Mail Iron Iron is a silvery white metal that oxidizes in moist air and forms rust. Iron is commonly used in nails for use in carpentry, and in some cooking and food storage utensils. Younger leaves go yellow, then white. Veins go lighter in color.
Older leaves stay green.
Iron becomes unavailable in pH conditions of 7.0 or more alkaline. Too much copper can interfere with iron uptake. Iron is required for chlorophyll synthesis. Iron is comparatively immobile in the plant, so deficiencies show up in the younger portions of the plant. Utilization of iron is dependent upon pH of nutrient and media and high pH or 7.0 will make iron unavailable.