Other uses[edit]
In horticulture it is used for treating iron chlorosis.[18] Although not as rapid-acting as iron chelate, its effects are longer-lasting. It can be mixed with compost and dug into to the soil to create a store which can last for years.[19] It is also used as a lawn conditioner,[19] and moss killer.
In the second half of the 1850s ferrous sulfate was used as a photographic developer for collodion process images.[citation needed]
Ferrous sulfate is sometimes added to the cooling water flowing through the brass tubes of turbine condensers to form a corrosion-resistant protective coating.
It is used in gold refining to precipitate metallic gold from auric chloride solutions (gold dissolved in solution with aqua regia).
It has been used in the purification of water by flocculation and for phosphate removal in municipal and industrial sewage treatment plants to prevent eutrophication of surface water bodies.[citation needed]
It is used as a traditional method of treating wood panelling[clarification needed] on houses, either alone, dissolved in water, or as a component of water-based paint.[citation needed]
Green vitriol is also a useful reagent in the identification of mushrooms.[20]