Fe-HEDTA, also called ferric HEDTA (CAS 17084-02-5), is a chelated form of iron used in plant nutrition. Chelation helps keep iron in solution. The choice of chelate depends on the pH and conditions around the roots, whether the crop grows in soil, a container substrate or a nutrient solution.
What Iron Chlorosis Looks Like
Iron chlorosis often appears on the youngest leaves first. Tissue between the veins turns pale or yellow while the veins stay green. Manganese deficiency can produce a similar pattern. High root-zone pH, waterlogging and impaired roots can also limit iron uptake even when iron is present in the soil. Iowa State University’s iron deficiency guide.
Root-Zone pH and Chelate Selection
Iron chelates differ in how well they hold iron in solution as pH rises. In strongly alkaline, calcareous soil, Fe-EDDHA generally retains iron more effectively than Fe-HEDTA. The NC State greenhouse chelate guidance compares the relative stability of these iron sources.
Citrus is one crop where soil conditions matter. The University of California iron deficiency guide identifies citrus as susceptible on alkaline soils and also points to poor drainage and impaired root health. Soil pH and carbonate content help explain why a chelate that works in one orchard may perform differently in another.
Fe-HEDTA in Nutrient Solutions
The pH of a nutrient solution can differ from the pH of the source water or the substrate. A Utah State University report on liquid fertilization identifies HEDTA as an iron chelate used for monocots in deep-flow hydroponics. In a recirculating system, crop species, solution pH and the rest of the fertilizer formulation determine whether the grade fits.
Fe-HEDTA Grade Specifications
For a fertilizer grade, compare the guaranteed water-soluble iron content, the fraction chelated by HEDTA and the conditions for use. These figures determine how much chelated iron a given mass of material supplies. The relevant values come from the specification and analysis for that grade.
View Unilong’s HEDTA-Fe (CAS 17084-02-5) product listing for product information. Company details are available on the About Unilong page.
Post time: Nov-11-2026