Ferrous Sulphate – Easy Dissolve – Soluble Sulfate of Iron (Damp)

Application Rates for Lawns

Rates of application can vary greatly depending on the desired effect and on the specific lawn. No two sets of circumstances will be the same and therefore a small area should be tested to satisfy yourself of suitability.

For Hardening and Conditioning Lawns

Test a small area with a 1% Ferrous Sulphate Heptahydrate solution (ie. 10gms/1L of water). If this does not give the desired effect a stronger solution can be used up to a maximum of 5% Ferrous Sulphate Heptahydrate (50gms/1L of water ).

A typical application for greening of grass would be 10-20g per Litre.  Be aware that at dilutions of 30g per Litre and higher, undesired blackening of moss could occur.  It is for this reason that Ferrous Sulfate is often included as an active ingredient in commercial lawn moss killing products.  Over application of the product could also result in blackening of the grass itself.

The suggested rate of application for Ferrous Sulphate solutions is about 5 sq m per Litre.

Please be aware that Ferrous Sulphate solution will cause staining if spilt or applied to hard surfaces such as concrete.  These brownish stains are effectively a form of rust and to remove them one will need to use an acid solution like Oxalic acid (used as a 5% solution).

When treating lawns with ferrous sulphate keep pets off the surface for at least one week. This protects their well-being and prevents transfer of residues onto hard surfaces (i.e. brown staining).

For application on agricultural pasture land / paddocks etc use at the same rates as above. Animals like horses must be kept of grasslands for at least 4 weeks before being allowed back to graze.

An over usage of Ferrous Sulphate can be harmful if the land being applied to has a low pH (very Acidic) as Ferrous Sulphate is naturally very acidic with a pH of 2.5. It is also recommended that the entire lawn be treated rather than specific areas to prevent certain patches becoming more acidic than others.

NOTE: We must stress that this information can only be used as a guideline and is given in good faith. We cannot be held responsible for any adverse effects that may be experienced as a result of use of the above product.

Acidifying Soil – Reducing pH with ferrous sulphate:

To reduce the pH of soil by 1 unit eg. to reduce a pH7 to a pH6 would require 2.25kg to 4.5kg for ferrous sulphate per 100sq feet of soil. This should be dug into a depth of 6 to 10 inches.As the acidiification occurs as the ferrous sulphate is biolologically degraded this can take several months so the process of acidifying is gradual. As it is important to avoid building up too much iron in the soil it is suggested that one should wait for 12 months before testing the pH again and repeating the process if necessary.