Lawns need mowing at least once a week in September, but there is a task that needs tackling before that - moss.

Aside from aesthetic damage, moss threatens the health of your grass plant by taking up growing space. 

As it grows thickly, moss prevents essential water and nutrients from lawn fertilisation from reaching your grass. This suffocates your lawn and hinders its ability to grow strong and healthy.

Gardening pro Nick from Lawn and Weed Expert has let slip the secret to reclaiming a verdant and luxuriant lawn by using iron sulphate against the invasive moss.

He advised: “Properly-applied iron sulphate moss treatment should kill off the moss, leaving the grass alone. It can even help fertilise your lawn: iron is as essential a nutrient for grass as it is for humans.”

Iron sulphate acts as an eco-friendly agent in turf care for eradicating moss and plays a crucial role in boosting grass health substantially so it grows “thicker fuller and greener”.

Upon its application, iron sulphate sets to work by swiftly desiccating the moss, facilitating its demise and also altering the lawn's pH levels, creating an environment where moss struggles to regenerate.

Nick explained: “Iron sulphate is the result of combining sulphuric acid (a strong acid) and ferrous hydroxide. Applying it to your lawn will lower the pH of the soil, past the point at which it’s made impossible to grow back.

“Simply mix iron sulphate with water and spray on affected areas, then sit back and watch the moss blacken and die off.”

The best time to apply iron sulphate to a lawn is the day after it has rained as the soil will be moist, which helps both the moss and grass absorb it better so it is more effective.

Applying iron sulphate on a warm and dry day can increase the risk of it simply sitting on top of the grass and not getting to the soil, which can risk the grass becoming scorched.

Iron sulphate is made with natural materials but it is still best to follow the instructions carefully when using it and avoid over-application, otherwise it can burn the grass.

Nick said: “Iron sulphate kills moss, but too much of the pure product can also harm your grass! Lime (the mineral, not the edible kind), bicarbonates, and zinc can all help combat iron toxicity.”

Once the moss has died, use a rake to gather up any of the dead foliage and dispose of it properly to prevent a moss infestation from returning.

Nick said: “After a course of iron sulphate moss treatment, the grass will need to be scarified to ensure the dead moss doesn't linger.

“Your lawn may need to be given a booster of sorts. Lawn fertiliser will help here. You could also overseed your grass after using iron sulphate.”