FERROUS SULPHATE AR HEPTAHYDRATE
Iron(2+) sulfate heptahydrate is a hydrate that is the heptahydrate form of iron(2+) sulfate. It is used as a source of iron in the treatment of iron-deficiency anaemia (generally in liquid-dosage treatments; for solid-dosage treatments, the monohydrate is normally used).
Mix at the rate of 1-2 Tablespoons per gallon of water or 5-8 Pounds per 100 Gallons of water. Flowers & Vegetables: Apply at the rate of 1/4 to 1/2 pound. (1/2 to 1 cup) per 100 square feet. Trees & Shrubs: Apply at the rate of 1/2 to 1 pound.
Dosage
On heating, ferrous sulphate crystals lose water and anhydrous ferrous sulphate (FeSO4) is formed. ... On further heating, anhydrous ferrous sulphate decomposes to form ferric oxide (Fe2O3), sulphur dioxide (SO2) and sulphur trioxide (SO3). So, the gas emitted smells like burning sulphur.