Ferrous Sulphate For Lawns

Ferrous Sulphate For Lawns – UPDATED 2021 – A Complete Guide

Ferrous sulphate or iron sulphate is one of the most popular products among homeowners looking for effective ways to keep their lawn turf green.

Iron and its compounds give a deep green color to the grass without promoting excessive growth, helping the lawn achieve a lush appearance.

They are a great alternative to nitrogen fertilizers and provide several other benefits.

In this guide, let us try to learn more about ferrous sulphate and its use for lawns. We discuss the application rate and method for ferrous sulphate to help users get maximum results.

Ferrous Sulphate For Lawns

Ferrous & Iron Sulphate For Lawns – A Complete Guide

Sulphate is one of the magical weapons used by gardeners of all experience levels around the world. Iron sulphate and ferrous are forms of iron and can make lawn maintenance a lot easier.

These products help green the grasses and lower the pH levels of the soil to encourage a healthy lawn growth. They are also used to control unwanted mosses and correct iron deficiency in the lawn.


Just like humans, iron is an essential nutrient for grass. If you find the blades a little yellowish, spraying some iron sulphate will give your lawn a bright green color in no time.

It will not only get your grass soft to touch but make it harder on the inside so that it stays protected against cold and diseases.

Pest Resistance

Ferrous and iron sulphate are acidic and make the lawn less appealing to worms and other creatures attracting birds. The grass also finds these acidic nutrients beneficial and becomes soft and fine rather than rough.

When used with some natural pest control remedy, iron sulphate can keep the lawn pest-free.

Moss Control

Ferrous sulphate is capable of blackening and killing moss while making the grass strong and green. Being an organic chemical compound, iron sulphate is less harmful to the environment than other chemicals.

The effects on moss are temporary and last for a season unless permanent moss eradication methods are undertaken.

Ferrous Sulphate Application Rate For Lawns

You can mix ferrous sulphate with water at the rate of 50-100 grams per 100 square metres of lawn to get a beautiful green color on the grass.

This application rate can be used throughout the year as long as the soil has some moisture and there is no strong heat.

The concentration should be increased to 150-200 grams if you want to use ferrous sulphate for disease resistance and turf hardening.

This application rate works for sports lawns and is performed in late autumn and winter.

Iron sulphate will blacken moss at this concentration and you can expect some temporary damage to the blades if conditions are not so cool. This rate of application should therefore be used when there is a lot of moisture available and there is no chance of heat.

If you want to blacken the moss severely along with turf hardening and grass greening, you can increase the rate to 400-500 grams per 100 square metre or undertake a repeat application.

Ensure cool conditions when applying at this rate to minimize possibilities of grass damage. The maximum safe limit for ferrous sulphate is 500 grams mixed in 5-10 litres of water for 100 sq. m.

Ferrous Sulphate Heptahydrate Lawn

Ferrous sulphate heptahydrate is a water-soluble iron and sulphur fertilizer used to improve the deficiency of iron and adjust the pH level of soil in the lawn. It is an excellent product for lawns with high alkaline soil.

It treats the soil so that plants can easily access the nutrients.

A popular treatment for treating iron chlorosis, ferrous sulphate heptahydrate is not so fast-acting but delivers long-lasting results. It can be dug into the soil by mixing with compost to create a store that lasts for years.

It is also an effective moss killer and lawn conditioner.

Ferrous sulphate heptahydrate applies iron to various turf, lawn and landscapes and helps correct yellowing of the leaves.

It comes as a water-soluble powder and enhances the greening of the lawn without increasing the growth. It boosts the photosynthesis and respiration in plants and promotes healthy growth of the lawn.

How To Apply Ferrous Sulphate Heptahydrate?

Ferrous sulphate heptahydrate comes in a powder form and can be applied as it is or sprayed by mixing with water. It is recommended that you use a broadcast sprayer for an even application.

These tools also make sure that iron doesn’t spread on other areas like paving. If you want to apply the product with hand, it is important to get familiar with the wind direction. Remember to wear a mask and protective gloves all the time.

Iron sulphate can easily stain skin, clothes, paving and concrete so care should be taken when spraying near paths and concrete.

You should wear old clothes and wash your hands after each use. If the product falls on the paving, a quick cleanup should prevent any permanent damage. For desired results, the entire lawn should be treated at once.

This is because iron has an acidifying effect and you can spot differences between treated and untreated areas.

Too Much Iron Sulphate On Lawn? Here’s What To Do

Iron sulphate is an excellent product for lawn maintenance but should be applied carefully. Higher concentrations of iron in the lawn can cause harm to the grass apart from killing weeds and moss.

If applied to wet grass or in heat, iron sulphate can burn the grass. Your grass loses its ability to absorb sunlight and turns grey or dull green.

While the right amount of iron sulphate depends on the type of grass and climatic conditions, a common symptom of too much is a severe darkening of the blades giving a black appearance to the lawn.

These effects are not permanent and should go away on their own. Iron lasts in the lawn for about a few weeks after which you should see your lawn recovering.