How to use a scarifier

Scarifying your lawn helps to remove weeds, moss and thatch from the lawn. Unwanted organic matter can look messy and prevent full, healthy grass growth. Scarifying your lawn strips back any unwanted organic matter. It prunes the grass and allows fresh grass seed the space to grow and flourish. Read on to find out what a scarifier is and when and how to scarify your lawn.

What is a lawn scarifier

A lawn scarifier is a machine on wheels, like a lawn mower, with a series of blades underneath. The blades turn over the lawn to tease out thatch (organic matter like dead grass), moss and weeds. An electric scarifier would suffice for a small garden. For a larger lawn, a petrol scarifier is ideal.

When to scarify your lawn

You should only need to scarify your lawn once a year. The spring or early autumn is best, when the grass has a chance to grow back and recover after scarifying. You should only scarify your lawn during a period of ideal weather, when there is sunshine, warmth and some rain. If you scarify when there has been heavy rain, or extreme conditions like a drought, you could do more damage than good. The grass will not be able to grow back for a long time after you have scarified it.

Removing weeds

Before you begin scarifying your lawn, you should first deal with any large weeds on your lawn by removing them with a trowel or small garden fork. You should also apply a moss killer to any patches of moss on your lawn around 1-2 weeks before scarifying. This will help to prevent the moss that you removed from spreading around your garden.

How to use a scarifier for your lawn

Before scarifying your lawn, cut the grass with a lawn mower on a low blade setting. This exposes the moss and thatch.

Next, use the scarifier the same way as the lawn mower, following the same lines you created when you cut the grass.

Set the scarifier blades on a high setting at first. If you go straight in with a low setting you can shock and damage the grass. Complete a few passes over the lawn, at different angles, lowering the blades a little each time.

As you scarify the lawn, you will remove the moss and thatch. Also, the blades will prune the grass to encourage thicker growth.

What to do after you have scarified your lawn

You can also aerate the lawn using an aerator (or 'hollow tiner'). This is a similar process to scarifying, but the aerator's tines punch tiny holes into the lawn. This improves drainage and encourages healthier grass growth.

As moss thrives in damp areas, aerating the lawn will help to prevent future moss growth by improving drainage. Aerating the lawn will also allow water, nutrients and air into the soil to feed the grassroots and improve grass growth.

Overseeding your lawn

Once you have finished scarifying your lawn, there may be bare patches where the moss and thatch once thrived. Overseeding involves scattering new grass seed over your lawn to fill gaps and promote thicker grass growth. This is a key process after you've scarified and aerated your lawn.

Scarifying and aerating your lawn leaves a nice seedbed for fresh seed to thrive. During overseeding, spread seed over the entire lawn but give special attention to fill the bare patches of lawn.

Once you have completed the overseeding, keep the soil moist with regular light applications of water. Though take care not to saturate the soil.

Keep traffic over the lawn limited following overseeding to give the seed a chance to grow. You can even cover areas of the lawn with a mesh to prevent birds stealing the seed!

When you mow the lawn in the weeks following scarifying, raise the height of the mower blades to give the seed a chance to establish.

Feeding the lawn

In the weeks following the laying of fresh seed, you can also use fertiliser to assist in the rich and healthy growth of your rejuvenated lawn. You should use a granular spring/summer fertiliser, as this has high levels of nitrogen and other nutrients like phosphate. Granular feeds perform better when the ground is still a little cold and growth is still patchy, so they work very well in spring.

For small areas, you can spread the fertiliser by hand. For convenience over larger areas, you can use a fertiliser spreader to ensure even distribution of fertiliser.

A good feed with a lawn fertiliser not only makes the grass greener. It also helps the grass to grow thicker, increases its strength and improves the health of the lawn. A well fertilised lawn is much more robust and better equipped to compete with weeds, moss and weather-related stresses.

If you feed the lawn again 6 weeks after the initial feed, it will remain strong and healthy all summer.

As the fresh seed takes to the lawn and starts to grow, you will soon notice the difference in your lawn. Where there was once thatch, weeds and moss, there will be healthy, rich, green grass. Also, as you aerated your lawn to improve drainage and allow nutrients into the soil. The new grass should flourish throughout the summer.