Gardeners struggling with mossy lawns this September can use a simple spray that both kills moss and feeds the grass, according to Lamara McBride from The Lawn Pack. The treatment, iron sulphate, is described as the most effective moss treatment for UK lawns and works without the harsh effects of many commercial products.
Why Lawns Become Mossy After Summer
Lawns are often weak after a dry summer, creating ideal conditions for moss to spread. Healthy grass can usually resist moss, but damaged areas struggle to stop spores from taking hold. While commercial moss killers are tempting, many are too harsh and add stress to the lawn, preventing proper recovery in autumn.
McBride explained: “The most effective moss treatment in UK lawns is Iron Sulphate (Ferrous Sulphate). When applied correctly it treats moss quickly, turns moss black within days [and] makes removal easier.”
How Iron Sulphate Benefits Grass and Kills Moss
Iron sulphate is a naturally occurring mineral compound that supplies grass with iron, supporting healthy growth. Grass needs iron to produce chlorophyll, which is essential for photosynthesis and gives grass its green colour. Feeding the lawn iron sulphate helps it grow more and become stronger, enabling it to fight off moss, weeds, and other unwanted plants in the future.
On moss, iron sulphate has the opposite effect: it dries out the spores and damages its cells, causing it to die off without the need for hand-pulling. This makes it one of the easiest ways to remove moss without harming the grass, increasing the chances of an emerald green lawn this autumn.
Steps to Apply Iron Sulphate Effectively
To begin, mow the lawn before applying iron sulphate, as this helps the treatment reach the moss more easily without being caught in long grass. Next, apply the iron sulphate evenly using a lawn spreader, following the recommended dose on the packaging. Leaving too much concentrated iron sulphate in one area risks scorching the grass.
Once the moss turns black or brown, rake it off the lawn and dispose of the dead material in the bin. Give the lawn a good watering, and it should be completely moss-free with minimal effort.
Moss on a lawn usually forms when the grass is unhealthy or needs better drainage. Iron sulphate removes moss, but it is best to scarify and aerate the grass sometime after applying the treatment. This addresses the underlying issue causing moss growth, helping the grass become thick and healthy in time for the colder seasons.
