How To Get Rid Of and Prevent Moss In Lawns in 4 Easy Steps

Lawn moss can form dense mats outcompeting grass for water and nutrients and making the lawn uneven and spongy to walk on. These primitive plants thrive in damp shady conditions and can quickly spread in struggling lawns.

How to get rid of moss in lawns

What causes moss in lawns?

Moss in lawns is a sign that there is an underlying problem with the lawn. This can be caused by any of several factors, including:

• Poor drainage
• Shade
• Lack of fertiliser
• Grass cut too short
• Heavy foot traffic

Scarifying lawn to remove moss

Ridding lawns of moss requires a two-pronged attack – firstly, to remove the moss and secondly, to stop it coming back.

Physically removing moss is done by scarifying, i.e. raking over the lawn to remove moss and thatch (dead grass). For small gardens this can be done by hand with a spring tine rake. For larger areas, it’s easier to use a mechanical scarifier.

If the moss problem is mild, it may be possible to get on top of it by simply scarifying and then improving the overall health of the lawn by regular lawncare to stop the moss coming back. It is important though to know the best time to do this a you can risk spreading the spore of the moss and making the problem worse.

April and September tend to be the best time to scarify moss as this is when there are no spores. Always mow before scarifying and try not to be too vigorous in spring, only scarify until you can see soil underneath.

Getting rid of moss in lawns however where there is a serious problem needs a combination of moss killer, scarifying and lawncare.

Scarifying moss before treatment is a good idea as if there is a really thick problem then the treatment doesn’t always get to work to the underneath sections so lossening it and thinning it will help the treatment get to work.

Moss killers

Chemical moss killers containing ferrous sulphate (also called sulphate of iron) are the most effective method of eradicating moss in lawns. Some chemical moss killers also include a fertiliser, which is useful for lawns where the grass has lost its vigour. Chemical moss killers are typically applied in autumn or spring when the weather is cool and wet, so that lawn seed sown afterwards to cover bare areas is most likely to germinate.

For gardeners who prefer not to use synthetic chemicals, organic moss killers are also available. These don’t contain ferrous sulphate they use bacteria instead to break down the moss. An advantage of organic moss killers is that since the bacteria effectively ‘digest’ the moss in situ it doesn’t go black and needs no raking out. Organic moss killers need a temperature above 15ºC (59ºF) to work and can be applied from late spring to autumn.

Tips on using a lawn moss killer

1. Moss killer can be applied either by hand or by using a manual spreader that can be pushed over the lawn. Chemical moss killers affect soil acidity levels, so it’s important to apply moss killer evenly across the whole lawn, not just in problem areas otherwise the lawn may grow back patchy and discoloured.
2. Always read the manufacturer’s instructions before applying moss killer, and use only at the concentrations specified because applying too much moss killer is likely to damage or even kill the grass.
3. Moss killer should be applied in fine weather but, again, always check the manufacturer’s instructions as some products require watering to activate.

Using ferrous sulphate (sulphate of iron) as a moss killer

Ferrous sulphate is often seen advertised as a solution to lawn moss and if you are using this on its own do make sure you apply it correctly as it is very easy to scorch the grass with a do it yourself treatment. Using a proprietary moss killer will always give you the correct amounts and therefore will be safer to use.

Caution on using moss killer (ferrous sulphate): When using a moss killer make sure that you always brush your shoes thoroughly after applying as the iron content can cause brown staining on many surfaces including the lawn, patios, decking, carpet etc. Best practice to remove shoes after use.

How to prevent moss in your lawn from coming back

Moss in a lawn indicates that there is an underlying problem with the lawn and unless this is fixed, the moss will return. The best way to discourage moss from coming back is to get the grass growing vigorously.

Lawn moss treatment in 4 easy steps

1. Aerate the lawn in autumn by spiking holes in the soil at regular intervals. For small gardens you can do this using a garden fork by pushing it in as far as possible and then removing it. For large areas it’s easier to use a mechanical aerator.
2. Re-seed sparse or bare patches of lawn. Shady areas of your lawn are always going to be more prone to moss so for these areas use grass seed mixes especially designed for shade.
3. After aerating and re-seeding the lawn, brush in a lawn top dressing. You can buy pre-prepared top dressing from garden centres or make up your own mix using three parts loam, six parts sharp sand and one part multipurpose compost. Spread it evenly over the lawn using a firm garden brush to work it in.
4. When mowing, take care not to cut the grass too short as this will stress the grass reducing its vigour and encouraging moss.
5. If shade is an issue cut back any branches or shrubs that are overhanging the lawn and use a shady lawn seed mix.

Moss in lawns doesn’t need to be a problem. With a little care and attention, you can turn a mossy lawn into beautiful green turf to be proud of.

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