Iron Sulphate

An inorganic fertiliser, supplying 20% to 25% of iron. It also supplies about 11% of sulphur. It is usually applied as calcined iron sulphate and is mainly used as a turf hardener, or turf tonic, and is typically applied at a rate of 4 to 6 grams per metre square. It is a major component of traditional lawn sand.

Iron sulphate acidifies the turf surface, reducing earthworm casting, weeds, algae and moss. The creation of an acidic (but not excessively acidic) surface layer can help to reduce the likelihood of some disease attacks, for example, Microdochium (Fusarium) and Take-all Patch.

It produces a dark green effect on a grass sward, although misapplication will result in the turf becoming blackened in appearance for up to a week, or so. Overuse will produce an acidic thin sward and will lead to a more easily worn surface, with bare areas. This can be a major problem where regular monitoring of the sward and soil is not carried out, although assessment and evaluation of applied materials is part of good turf management practice so this situation should not arise in modern grounds management.

It is also called Sulphate of Iron or Ferrous Sulphate.