Scarifying and Aerating the Lawn: Here’s How It’s Done

Aerating and scarifying the lawn
You should aerate or scarify the lawn from time to time. This will keep it fresh and healthy.

Why Should You Scarify the Lawn?

You can determine whether you should scarify your lawn easily with a test. Pull a small rake or a cultivator loosely through the turf. If old grass cuttings and bits of moss remain hanging on the tines, it’s time to scarify.

A large amount of weeds in the lawn are also a sure sign that the lawn should be scarified. Because in this case, the lawn grass growth is inhibited.

A lack of nutrients may be a reason for this. However, a thick layer of lawn thatch can also prevent the oxygen supply to the lawn. Scarifying helps here.

How Does a Scarifier Work?

A Bosch scarifier at work
A scarifier penetrates the lawn with small blades. In this way it removes moss and lawn thatch.

Scarifiers have a horizontally installed spindle or axle. This is covered in rigid or rotating blades at relatively short distances. The motor drives the axle. The blades move and scratch the turf a few millimetres deep. At the same time they remove moss and lawn thatch.

What Is Important when Scarifying?

Your lawn should be completely dry before you scarify. Then adjust your scarifier to the correct height. The blades should not penetrate the turf deeper than 0.04 inches. With the UniversalVerticut 1100 from Bosch, you can easily adjust the height.

Then work with the scarifier as evenly as possible over the entire lawn surface. First, move lengthwise. Then finish by working breadthwise. Push the guide rails downwards in the curves. Otherwise the blades could mark here too deeply.

Which Scarifier Do You Need?

Bosch scarifier
A scarifier gives your lawn air to breath again. So it can thrive.

A petrol operated scarifier is particularly recommended for very large areas. This means you won’t be tied to a power connection and you don’t have to watch out for the cable. Petrol scarifiers also often weigh more than electrically powered equipment. This enables them to penetrate the turf more deeply.

On the other hand, an electrically operated scarifier is easier to manoeuvre. It is suitable for smaller areas which are not easily accessible. But you do need to keep an eye on the cable. However, as you will rarely use the equipment more than twice a year it’s not a problem. If the electrical scarifier is too light, you can easily weigh it down with a sandbag.

Manual scarifiers need neither electricity nor petrol, however they are extremely laborious. Still, they are useful for very small areas or individual thatch patches.

When Should You Scarify the Lawn?

April to September is the right time to scarify the lawn. If you use the lawn intensively in the summer, you should dethatch it in the spring or wait until late summer to carry out this maintenance. After scarifying , the lawn needs a few weeks to recover from the process. You should let it rest during this time.

Start the maintenance program for your lawn in the spring by fertilising. As soon as the daffodils open their buds, the grass has also started to grow again. From this point you can fertilise and you should also start mowing again. Reach for the lawnmower yourself, or let something else do the work for you: A robotic lawnmower will move out independently and cut your lawn to the desired length.

About two weeks after fertilising is generally the time to mow the lawn again. Mow the lawn down to a height of 2 cm or leave the work to a robotic lawnmower. Now is the perfect time for scarifying. The lawn is now well supplied with nutrients. It can therefore tolerate scarifying particularly well.

Don’t wait too long to scarify. It is often very warm and also dry by May. If you wait until then to scarify, you will have to water extensively afterwards to close up the turf again.

Bosch robotic lawnmower
A robotic lawnmower will take care of the recurrent work for you. Program it in such a way that it sets off independently.

Scarifying the Lawn: Here’s How To Do It:

Scarifying is anything but sorcery. It’s really easy with these tips:

  1. Only dethatch completely dry lawns.
  2. Set the correct height. The blades should penetrated up to 3 mm into the turf.
  3. Mow the lawn to about 2 cm tall.
  4. Scarify the entire lawn. Don’t stop and move the equipment generously over the lawn surface.
  5. Dethatch first lengthwise then breadthwise.
  6. Push down the guide rails when changing direction. The blades are then in the air and cannot damage the turf.
  7. Resow bare patches in the lawn with lawn seeds directly after scarifying.
  8. Rake up the lawn thatch from the lawn surface.
  9. If the lawn is growing in heavy soil, spread a layer of building sand about 2 cm thick after scarifying. This will improve the air balance of the soil.

Why Should You Aerate the Lawn?

In addition to scarifying, you should also work the lawn from time to time with a lawn aerator. Because if the lawn roots develop poorly if they receive insufficient oxygen. The lawn suffers and no longer looks as beautiful. A poorly aerated lawn is susceptible to moss.

What Happens when the Lawn Is Aerated?

Aerating the lawn
Aerate your lawn with a pitchfork. This will allow more oxygen to reach the roots again. ©MSG/Martin Staffler

When aerating the lawn, you loosen the soil under the lawn surface. This allows more oxygen to reach the lawn roots. Water can also seep in more easily again. The lawn then grows better and thicker again and also looks healthy once more.

Heavily used lawn areas should be aerated every one to two months. If you hardly use the lawn at all, it is sufficient to aerate once a year.

Which Soil Should Be Aerated?

In general, any soil can be affected by a lack of oxygen. The problem occurs particularly frequently in loamy soils. The reason for this is the fine granular structure of the soil. When stressed, the soil becomes highly compacted. So hardly any air can reach the roots.

Aerating the lawn is a sensible measure to take here. However, it is most effective when combined with other measures. A very loamy soil should be sanded from time to time, for example, in order to loosen the soil structure.

Aerating loamy soil
Loamy soils become compacted very quickly. Aerate them regularly and loosen the structure with sand. ©Flora Press/BIOSPHOTO/Jean-Michel Groult

When and How Should You Aerate the Lawn?

The end of March to the start of October is a good time to aerate the lawn. Chose a time when the soil is damp but not wet.

How Can You Aerate the Lawn?

You have three options for aerating the lawn:

  1. Digging fork
  2. Aerating fork
  3. Lawn aerator

If you only have heavily compacted soil areas in a few spots, you can rectify these with a digging fork. Push the tines completely into the soil in the affected areas and wiggle the digging fork around. This makes the holes a little larger. In this way, you create channels that the water and oxygen can use to get into the soil. Then fill these channels with fine grained sand.

An aerating fork not only makes holes in the ground. It has hollow tine with which it removes the earth from the pierced holes. This allows a lot of air and water to penetrate into the ground. Here, too, you can fill the channels created with sand.

Although you can also aerate the lawn by hand, the easiest way is with a lawn aerator. With the UniversalRaker 900 from Bosch, you can provide your lawn with fresh air to breath particularly quickly and easily.

Lawn aerators are considerably more gentle on lawn turf than scarifiers. This is an advantage. However, in direct comparison, they remove less moss from the lawn. In the ideal case, you should use a combination of both processes.


Sanding the Lawn

In order for the soil to remain permanently loose and allow water and oxygen to the roots, you should not only scarify and aerate the lawn, you should also sand it in the spring. Use about 5 l of sandbox sand or building sand per square metre of lawn. Level off the sand with a broom or rake.

The rainwater will rinse the sand bit by bit into the aeration holes created and thereby ensure permanently open channels for water and air.

Scarifying and Aerating the Lawn: Here’s How It’s Done
Scarifying and aerating the lawn frees to from moss and lawn thatch. It also provides it with important oxygen. It will reward you with strong, healthy growth. Here’s how to scarify and aerate.