Iron Sulphate - Soluble Slow release powder [size: 1kg]

19.5% Iron, 11.5% Sulphur

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Iron (Ferrous) Sulphate Heptahydrate Powder (Mostly soluble but not the fast acting chelate type)

Is in a slow release form, 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 (or applied on top of) to create a store which can last for years.

The Agricultural, Lawn and Garden, and Turf Management industries use Iron Sulphate to correct iron chlorosis or deficiencies in plants and soils, to eliminate moss, to reduce alkalinity (pH), and as a trace element or micronutrient in fertilisers. It also can suppress worms and work as a turf hardener to help against disease.

Iron products encourage deep greening of turf grasses without encouraging excessive growth, helping lawns achieve a lush appearance without the overuse of nitrogen fertilisers.

Soil Test

Before applying any amendments or chemical treatments to your lawn, conduct a thorough soil test. Purchase a kit at a local garden centre or consult a quality landscape service, if available in your area. Otherwise Plant Doctor can arrange these tests to be done on your behalf.

Choose a test that assesses pH, organic matter content and chemistry. Iron deficiency causes yellowing of leaves, called chlorosis, and poor overall health of turf grasses. In alkaline soils with a pH well above 7.0, iron becomes bound to soil particles and unavailable for plant root absorption. Lowering your soil pH to a mildly acidic condition helps free iron, supporting healthier lawn growth.

Soil Acidification

Our Iron Sulphate contains more than 19.5% iron, along with 11.5% oxidised Sulphur. When used as a soil treatment, naturally occurring soil microbes break down the component minerals. This frees Sulphur and Iron that grasses can use for photosynthesis, chlorophyll synthesis and to build essential enzymes and proteins. During the conversion process, a small amount of sulphur is released into the soil as Sulphuric acid. This is a benefit to alkaline soil, as the process lowers its pH. However, too much Iron Sulphate can drive down soil pH too far, creating a root environment that is excessively acidic.

Lawn Fertilisation

Many lawn fertilisers contain a high amount of Nitrogen to support vigorous, green growth, but there are drawbacks to using too much nitrogen-based fertiliser. Excess Nitrogen can encourage lawn diseases and insect pests. Also, Nitrogen is easily leached (run-off) from soils by rainwater or irrigation. It may find its way into drinking water tables and sensitive aquatic ecosystems. In streams, rivers and estuaries. Using Iron Sulphate as a fertiliser may be a more environmentally friendly alternative in many cases.

Moss Control

If mosses have invaded portions of your lawn, Iron Sulphate can help control them. Since Iron Sulphate is an organic chemical compound that also provides soil nutrients, it poses much less risk to the environment than many synthetic herbicides. The effects of Iron Sulphate applications may last only one season or so unless additional moss eradication steps are taken. These include manual removal of any residual moss, sowing grass seed varieties best suited to your climate and dethatching your lawn regularly.

Analysis: Fe:>19.5%; S:11.5%

Application rates:

To correct iron deficiency:

Use 20-30g per square metre. Spread evenly over the surface (or mix with water and spray on) and water in well. Re-apply every season, or as required.

For soil acidity:

Use 25-35g per square metre. Spread evenly over the surface (or mix with water and spray on) and water in well. Re-apply as required.

To eliminate moss:

Use 10-20g per square metre. Spread evenly over the surface and water in well (or mix with water and spray on). Can be applied at most times of the year, spring being the most common time, as this is when moss treatment is often carried out. However, frequent applications (every 6 – 8 weeks) from late autumn, through the winter into early spring will certainly help prevent moss from forming during this time.

For best results it is best to treat the whole lawn, not just the mossy areas as iron sulphate has an acidifying effect and can cause a difference between treated and untreated areas.

When the product has been applied with a spreader it is important to stay off the lawn until it has been watered thoroughly.

Sulphate of Iron is a very fine powder and it is generally spread in its powder form (but can be or mixed with water and sprayed on), you can spread it using a broadcast spreader which is recommended as it gives an even and steady application. Broadcast spreaders also ensure that the iron does not blow onto paving etc. or worse again right into your face.

If you choose to spread the product by hand you should do so on a clam day and become familiar with the direct of wind. Avoid spreading Iron Sulphate into the wind and wear protective gloves and a dust mask at all times.


Iron sulphate can stain paths, concrete, paving, clothes and skin, so always wear old clothes, wash hands after use and be careful when applying near concrete and paths etc. if a small amount of the product blows onto paving etc. then a quick sweep should prevent any lasting damage.


Keep pets off treated areas for at least one week, Horses should be keep off treated areas for at least 4 weeks and not allowed to graze.


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