Affected leaves turn a yellowish color while the leaf veins remain a dark green.
Iron chlorosis is caused by the plant not being able to obtain the iron it needs. Iron is needed for the production of chlorophyll and therefore, a lack of iron results in a loss of the green color in the leaves. In severe cases, leaf color may change from yellow to white to brown. Though there is usually plenty of mineral iron in our Kansas soils, it becomes progressively more unavailable for plant use as the pH rises above neutral. If the pH of your soil is above 7.0, use sulfur to acidify it and bring the pH down.