Sulphate of Iron Sulphate of Iron is commonly used to reduce the alkalinity of soils, helping make available the natural elements and nutrients essential to the healthy cultivation of plants that thrive in acid conditions. All calcifuge (lime-hating) plants such as azaleas, magnolias and conifers, as well as many ericas and alpines, can benefit from a regular top dressing of Sulphate of Iron. Sulphate of Iron: Reduces alkalinity of soil Improves cultivation Contains iron sulphate heptahydrate In addition to improving the habitat, Sulphate of Iron supplies iron – a vital trace element. Before planting, work into the soil. For established shrubs and plants, apply as a top dressing during the growing season and lightly hoe in. Be careful not to spill onto the leaves. Avoid Sulphate of Iron lodging on leaves or stems. Wear gloves during application as skin irritation may occur. Sulphate of Iron can also cause serious eye irritation and harmful if swallowed.