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

What causes moss in lawns?

In a healthy lawn, the grass will usually grow strongly enough to prevent moss, so a heavy growth of moss in lawns is a sign that there’s a problem with the lawn. Some of the most common problems are:

Poorly drained lawns

Moss grows well in damp conditions, so it’s often found in poorly drained lawns. The drainage problems may be due to inadequate soil preparation before the lawn was sown, or soil becoming compacted over time due to heavy foot traffic. Grass struggles to grow in these conditions, and can quickly be out-competed by moss.

Shade

Moss grows well in shade, so it can quickly colonise shady lawns where grass growth tends to be weak and patchy.

Acidic soil

Although moss can grow in practically any soil, it’s more common in acidic soils, mainly because lawn grasses tend to struggle in these conditions.

Lawns mown too short

Regularly mowing the lawn too short weakens the grass, allowing moss to move in.

How to get rid of moss in your lawn

Preventing moss in your lawn requires a two-pronged approach:

1. Removing the moss, either by raking it out or with the help of lawn moss killers.
2. Improving lawn health to reduce the risk of the moss growing back.

Scarifying to remove moss from lawns

The first step in getting rid of moss is to scarify the lawn, using a spring tine rake or a mechanical scarifier. Rake firmly over the lawn to loosen the moss. If your lawn only has a small amount of moss, scarifying by hand may be enough to remove it. If there’s a lot of moss in the lawn, scarifying before applying moss killer will thin the moss out, allowing moss killer to penetrate and deal with the remainder. 

Raked-out moss can be added to your compost heap, but it breaks down very slowly, so add it gradually over several weeks and layer it with other plant material.

Using moss killer to remove moss from lawns

Heavy moss growth can be tackled with moss killers.

Moss killers usually contain ferrous sulphate (also known as sulphate of iron) which is very effective at killing moss in lawns. Our range of moss killers includes products that solely target moss, and also products like Miracle-Gro Complete 4 in 1 which kills lawn weeds as well as moss. They also feed the lawn, thickening up weak patchy grass so that moss is less likely to grow back. Moss killers are available in both liquid and granular form, so you can choose the product that best suits your garden’s needs.

When to apply moss killer

The best time to apply moss killer is in autumn when the grass is growing strongly and can cope with vigorous scarifying. You can also apply moss killer and scarify in spring to remove moss that has grown over winter, but take care not to damage new grass roots when scarifying.

How to apply moss killer

Moss killer for lawns can be spread using a lawn spreader. The ferrous sulphate in moss killer affects soil pH, which in turn affects how the grass grows, so it’s important to spread moss killer evenly to avoid your lawn looking patchy.

Using too much moss killer can harm or even kill your grass, so always follow the product instructions and use the product at the right concentration.

Keep pets and children off the lawn until the moss killer has been watered in and dried.

Once the moss turns black (typically 2-3 weeks after moss killer application), rake it out using a spring-tine rake. This dead moss can gradually be added to your compost heap, layered with other plant material. Check the packaging instructions for details on how long the resulting compost should be left before it is safe to be used in the garden.

Bare patches of soil can be re-seeded with grass seed, but again, check the packaging for details of how long to wait before re-seeding.

Important tips for applying chemical moss killer

• Always read and follow the application and safety instructions on the packaging.
• Mow the lawn and scarify before applying moss killer.
• Apply moss killer when the weather is fair and the soil is damp. Don’t apply if heavy rain is forecast, as the rain will wash the product away.
• Ferrous sulphate can stain surfaces like paving, decking and carpets, so always clean your boots or shoes after applying moss killer – we recommend removing your shoes before walking on patios or coming indoors.

How to prevent moss growing back

Once moss has been dealt with, it’s important to fix the conditions that encouraged its growth so that it is less likely to return.

• Regular lawn maintenance in spring and autumn controls moss in lawns by promoting the growth of strong healthy grass.
• Aerating your lawn helps prevent moss by breaking up compacted soil and improving drainage. You can aerate small areas by hand using a garden fork or a hollow tine aerator or hire a mechanical aerator for large lawns.
• After aerating your lawn, brush in lawn dressing, a combination of sand, organic material and lawn food. When worked into the holes left by aerating, it improves soil structure and drainage, promoting healthy grass and reducing the risk of moss re-growth.
• Avoid cutting your lawn too short, as this weakens the grass. Ideally, never cut off more than one-third of the grass blade length.
• Reduce shade on the lawn where possible by cutting back shrubs and pruning trees. Sow shade-tolerant grass seed in shady areas, or remove the lawn in these areas and replant with shade-loving plants.

A 4-step plan to get rid of moss in your lawn and stop it coming back

Mossy lawns don’t have to be a problem! Here’s our four-step plan to tackle moss in lawns:

1. Scarify your lawn to rake out as much moss as possible
2. Apply moss killer to deal with heavy moss growth.
3. Aerate and top-dress your lawn to improve drainage and reduce the risk of moss growing back.
4. Prune shrubs and trees to maximise the amount of sunlight reaching the lawn and re-seed shady areas with shade-tolerant seed.