How to get rid of moss in a lawn

What is lawn moss?

Moss is the term used for a collection of primitive plants that grow in many places around the garden.

Where do you find it?

In gardens, moss grows predominantly in lawns, but it can grow almost anywhere where conditions suit it, from roofs to soil. There isn’t a specific type of lawn moss.

Benefits and uses of moss

Moss creates a good habitat for small creatures which in turn provide food for birds, amphibians and mammals such as hedgehogs. Birds and hedgehogs also harvest moss to use in nest-building. Rake or gather your own moss to use in a variety of ways, such as lining hanging baskets, as a base for decorative garlands, especially at Christmas time, and to create kokedama or moss balls.

In shady or poorly drained spots where grass doesn’t thrive and where foot traffic is low, turn the ‘problem’ of lawn moss on its head and get rid of grass instead, in favour of growing a moss ‘lawn’, and enjoy its rich tapestry of greens and velvety textures.

Symptoms of moss problems

Lawn moss may become a problem when its abundant growth out-performs grass. It can also cause issues in high-use areas where moss becomes worn and leaves bald patches, or in periods of drought when moss dies and is slow to regrow.

What causes lawn moss?

Moss in lawns is a symptom of one or more issues, including compacted soil, poor drainage, low fertility, insufficient light and extremes of pH level. It can also grow where grass has been mown too closely.

Long-term lawn moss removal

Tackling moss by addressing the underlying cause or causes is the only long-term way to solve the problem. Proprietary moss killers eliminate or reduce moss in the short term, but it will return unless the underlying issue is dealt with.

Problems and solutions

• Compaction and poor drainage: puddles that are slow to disappear are an obvious sign of drainage problems, particularly if your garden is on heavy, clay or silty soil. However, any lawn can become compacted on the surface after heavy use. Tackle in autumn, either hiring a hollow-tine aerator for larger lawns or a pronged aerator for smaller ones. Alternatively, use a garden fork to ‘spike’ small areas, rocking the fork backwards and forward to open out the holes. Fill the holes with sharp sand so your lawn is honeycombed with lots of drainage channels
• A build up of thatch: a layer of dead grass and moss known as ‘thatch’ can accumulate on the lawn and contribute to compaction and poor grass growth. Removing it is known as ‘scarifying’ and gives the grass room to grow. Rake out in autumn or spring using a lawn rake or a mechanical scarifier (either manual or powered). Powered scarifiers are available to hire as well as buy
• Poor grass growth: if grass is patchy and slow to grow, lawn moss can take over. Encourage vigorous grass growth that out-performs moss by feeding in autumn and spring with a proprietary lawn feed suitable for the season
• Too much shade: in areas of deep shade, either use a grass seed or lawn turf specifically formulated for shady conditions or accept defeat and replace with ground cover plants or hard landscaping
• Lawns mown too short: while it’s tempting to cut grass really short in an effort to extend the time between cuts, this creates bald patches that are an open invitation to moss and wild plants. Avoid cutting the lawn too short to maintain good grass cover over the whole lawn
• Acidic soils: a soil with a low pH (around 5.0) is acid and ideal for moss growth. Check the soil pH using a simple test kit. Applying lime raises the soil pH

Lawn moss killer products

A wide range of proprietary moss killing products is available to buy and these kill only moss, not grass. The best moss killer to apply depends on your personal choice of chemical versus non-chemical product. Be aware that many moss killers are chemical-based and may impact wildlife, as well as needing caution if children and pets use the lawn. An organic product free from synthetic chemicals is the safest choice.

Whatever product is used, always apply as instructed according to the product instructions and take care to follow all safety advice.

Organic moss killers

Bacteria-based moss killers work by digesting moss, breaking it down and feeding the lawn at the same time. A great advantage of this type of moss killer is that the dead moss doesn’t usually need raking out.

Where to buy organic moss killers online

• Crocus
• Marshalls
• Suttons

Chemical-based moss killers

Synthetic moss killers are based either on sulphate of iron (ferrous sulphate) or combined with lawn fertilizer as a moss killer and lawn feed. Treated moss blackens and dies. It will then need raking out, either by hand with a lawn rake or using a mechanical scarifier. Take care not to apply at more than the recommended rate or it may kill the grass as well as the moss.

Where to buy chemical-based moss killers online

• Thompson & Morgan

When and how to apply moss killer

The best time to apply moss killer to lawns depends on the type of product. Apply bacteria-based products from spring to autumn when the temperature is a minimum of 15°C. Chemical moss killers are usually suitable to apply either in spring or autumn.

Apply moss killer when the lawn is dry and the weather is fine. An applicator is best to use for an even distribution at the recommended rate, rather than applying by hand.