Control and prevent lawn moss

Do you have moss in your lawn? Use this guide to find out why you have it and what steps you can take to kill moss and stop it taking over!

Moss in lawns thrives during wet weather when and gardens are flooded or waterlogged creating problems everywhere in the garden.

Moss is a serious problem that is usually found where the lawn remains wet for prolonged periods, where drainage is poor and the lawn is in the shade. Moss is the name for a group of primitive non-flowering plants that quickly spread as a spongy mass on undisturbed soil.

Moss reproduce from millions of microscopic spores produced on the leaves that then spread away from the mother plant on rainwater.

Closeup of moss in a lawn

When you find moss in your lawn it is a good indicator that:

  1. The ground remains wet for long periods.
  2. The nutrient levels in the soil are low.
  3. The soil is compacted and lacks organic matter.
  4. The grass may be cut too short or even scalped down to bare earth.
  5. The area is shaded from regular sunshine, possibly from overhanging trees or shrubs.

To kill moss in your lawn, burning off moss with a suitable lawn treatment is easy - but unless the conditions that favour its growth are changed, then the moss will return, springing up from spores that remain on the soil surface.

Apply a lawn treatment containing a mosskiller, Miracle-Gro EverGreen offer a comprehensive range of products which work to control moss in lawns:

Having used a lawn treatment, try to remove the causes for lawn moss. Spiking the soil with a garden fork or hollow-tine aerator will improve drainage. Overseeding with a grass seed mixture especially for shaded areas such as Miracle-Gro EverGreen Shady Lawn Seed will improve the vigour of the lawn.

Miracle-Gro EverGreen Shady Lawn Seed

How to treat and then prevent lawn moss

Do not try to rake out the moss before it has been killed by a lawn treatment, because this will only spread the spores and make matters worse. Apply a moss control in spring and the moss will turn brown in a week. Then you can rake out the debris.

To prevent the moss from returning, you need to take action to improve the conditions for the grass and make it inhospitable for the moss.

Check the cutting height of your mower

Check the cutting height of your mower. Never scalp a lawn too short. This will weaken the grass and leave the soil open to moss invasion.

Where moss is a problem, leave the grass so that it is at least 2.5cm (1in) long at all times. Mow regularly (at least once a week) to encourage the spread of grass. In autumn and winter leave the grass even longer. See recommended cutting heights in our lawn cutting article.

Improve drainage

Improve drainage so the soil doesn’t remain permanently wet. This means spiking the affected area to let in air, improve drainage and generally reduce the compaction of the soil. There are two methods:

  1. For slight moss problems drive a garden fork into the area at 15cm (6") intervals as deep as possible.
  2. Where moss is a continual problem, use a hollow thin tool that can be driven into the lawn to remove plugs of soil at regular intervals. These plugs need to be brushed off the lawn and the holes filled with good, enriched soil. This enriched dressing will improve the organic content of the soil, improve drainage and reduce compaction. As a result, roots of grass plants will be encouraged to root even deeper and the grass should become thicker and healthier.

Avoid watering the lawn in summer, unless the grasses are wilting from lack of moisture. If watering is essential, spike the area with a garden fork to reduce run-off and to ensure good drainage of any excess water.

In areas that get water-logged regularly you will need to build a soak-away system to take away any excess water. This could be a simple soak-away sunk at the lowest point of the lawn. Dig a hole 60cm (2ft) square and 1 metre (1yd) deep. Fill the bottom 60cm with broken bricks and other rubble - top this with a 15cm (6in) layer of small stones topped off with a layer of free-draining top soil. If the lawn still remains wet, then you may need to dig out gravel tunnels 30 cm down which will naturally take water from the lawn to the soak-away.

Where possible, ensure your lawn gets as much daylight as possible

Wherever possible cut back branches of trees and reduce the height of hedges to allow the sun to reach all areas of the lawn. Sun and wind will dry out the soil surface and moss will therefore be discouraged. If shade can’t be reduced, bite the bullet and turn this area of lawn into a bed and plant up with shade loving plants.

Regularly feed your lawn

Starved grass can’t grow well and will dominate your lawn, to the point it can out-compete the moss in lawns unless it receives supplementary energy. Feeding the lawn in spring, again in the summer and finally in autumn will help no end.

In spring and summer use a lawn product that also contains a moss killing ingredient and slow release energy to feed the grass for months not just weeks.

Using Miracle-Gro EverGreen Complete 4 in 1 prevents moss

In September or October use a lawn product specifically designed for Autumn use, to help grass to strengthen over-winter and control any existing moss that would otherwise spread throughout the dark days of winter. A well-fed lawn is thick, strong and vigorous because it encourages the growth of grasses and inhibits the growth of moss.

Regularly aerate your lawn

The main reason for aerating is to alleviate soil compaction. In autumn or early spring, take out plugs of soil with a hollow tine tool and brush an enriched lawn soil into the holes that have been created and leave a thin layer of the material on the soil surface so this can be pulled into the ground by worms. This is especially beneficial on light sandy soils that are shallow. This article gives you a detailed ‘how to guide’, for aerating your lawn.

Reseed your lawn with a shade tolerant grass seed mix

Where bare patches have occurred as the moss dies off, re-seed the area with a shade tolerant grass seed mix.

A good shade tolerant grass seed should be a mixture of carefully selected varieties of grasses including fescues and Browntop Bent, that have been developed to give good shade and drought resistance. The best time to sow this type of mixture for quick germination of grass seed, is mid- spring (April) or autumn (October).

Rake the soil to make a fine seed bed and sprinkle the selected grass seed over the area lightly. Cover the seed with good soil and keep moist until the grass seed germinates. If the whole lawn is thin, then over-seed the complete lawn with a sprinkling of the shade tolerant grass seed applied in the autumn or spring. In just a few weeks you will have a thick, dark green lawn that will be strong enough to fight off moss problems.