Scarifying the lawn correctly – why, when and how?

Scarifying the lawn correctly - why, when and how?

Moss, weeds, and mowing residues torpedo a dense, velvety green lawn. Scarifying eliminates the problems and optimizes the oxygen supply to the grassroots.

Here you can read a tried and tested guide with practical tips and tricks for hobby gardeners. How to scarify your lawn properly.

Why is scarifying useful?

If moss, weeds, and rotten clippings gain the upper hand in the lawn, young lawn grass can no longer penetrate the thatch. When scarifying, the turf is scored a few millimeters deep.

Rotating knives comb out the green area. The green rubbish remains on the lawn surface and is simply swept away. As a result, the roots of the grass can breathe deeply again and process nutrients better.

Scarifying the lawn – questioning allowed

Lawn experts’ passionate pleas suggest that it is necessary to scarify a lawn every year. Before you devote yourself to the time-consuming and exhausting procedure, you should critically question the relationship between effort and success.

So that you can make a clear decision without much headache, we have compiled the relevant criteria for yes or no for you below:

Yes no
dense moss pads little to no moss
plenty of weed occasional weed growth
bald patches from thatch dense turf without gaps

Don’t you want to rely on purely visual factors before deciding between yes or no? Then use a garden rake or a cultivator.

Loosely rake the lawn in question at various points. If moss, weeds, and old clippings get caught in the tines, you should scarify your lawn.

When is the best time of year?

Basically, you can scarify your lawn throughout the growing season. The thermometer announces when the starting shot will be fired. Temperatures should not drop below 10 degrees Celsius (50F) at night either. This specification also applies if you want to determine in the fall when you can comb out a green area.

The best time of year to scarify a lawn is in spring during the months of March and April. In wine-growing regions with mild winters, the time window can open as early as February.

If you want your lawn to go into the winter freshly combed, scarify a second time in September or October. Again, gardeners in mild climates enjoy the privilege of being able to scarify a lawn well into November.

Scarifying the lawn correctly

How often is scarifying useful?

A mossy lawn with dense weed growth should be scarified at least once a year. So that you can enjoy the velvety-green carpet of the lawn for a long time, spring is the best time.

A heavily used sports and play lawn benefits from combing out the green area a second time in autumn. Without the stress of moss, weeds, and leftover clippings, ornamental and shady lawns are of course better prepared for the winter.

Exclusion criteria at a glance

After a long period of rain, your lawn is so soggy that scarifying can have fatal consequences. Scarifying a lawn in winter is also doomed to failure. The following overview summarizes the conditions under which you can expect significant problems:

exclusion criterion damage picture
wet lawn destroyed lawn
damp lawn partially plucked noble grasses
frozen lawn no scarifying effect
young lawn combed out seedlings and young grasses

If you enjoy colorful flowers in the middle of the lawn, you should carefully consider whether you comb out moss and weeds or not. Scarifying a lawn despite having flowers destroys the splash of color for a long time.

Scarifiers pull everything out of the ground that they can get their hands on. Flower roots are not spared by the rotating knives.


As a disfigured patchwork quilt, a lawn confronts its gardener with a decision: till or scarify? You should not underestimate the regenerative capacity of noble grasses.

Before you peel off a lawn and create a new one, a test with the scarifier is worthwhile. Previous fertilizing revitalizes the last lawn grasses. After two to three weeks, comb out the green area, spread a reseed and examine the result after a few weeks.

Scarifying succeeds manually and mechanically

It is up to you as a gardener to decide whether you scarify a lawn by hand or with a machine. A hand tool uses rigid steel blades mounted along an axis between two wheels. Moss and weeds are removed by pulling the hand scarifier through the turf while applying pressure.

Manual scarifying undoubtedly requires considerable effort and is primarily useful for small lawn areas.

Motorized scarifiers work with rotating knife rollers that slit the ground and pull out thatch. The working depth can be set individually. The devices are available in specialist shops as either electric or petrol scarifiers.

Scarifying the lawn correctly

The correct order to scarify

The key to success is the correct sequence of work steps. The following list provides an overview of the sequence in which you should properly scarify your lawn:

  • 2-3 weeks before: Mow the lawn to a blade height of 4 cm (1.5 inches) and fertilize
  • On the selected date: mow the lawn to a blade height of 2-3 cm (1 inch), scarify and sweep away
  • After scarifying: sand and/or lime if necessary, sprinkle regularly
  • 7 to 10 days after scarifying: overseed and blast any areas that are visibly bare
  • 3-4 weeks after scarifying: mow for the first time and fertilize again

To turn a scarified lawn into an even, representative green area, please be patient after scarifying. Allow sand, lime, and overseeding to take effect before you mow. The stalks should have reached a height of at least 8 cm (3 inches).

Step-by-step instructions – How to scarify in an exemplary manner

In order to properly scarify a large lawn area of ​​around 200 square meters (2000 SF), please plan one working day. Here’s how to do it competently, step by step:

  • Mow lawn to 2 to 3 cm (1.15 inches)
  • Set the scarifier to the desired working depth
  • Position the device parallel to a lawn edge and fire it up
  • Scarify the lawn lengthways slowly and without stopping
  • Sweep off clippings with a rake
  • Comb and sweep the green area in the transverse direction
  • If necessary, sand and lime the lawn
  • Finally, sprinkle the scarified lawn

Worry lines on the forehead makes home gardeners wonder how deep a lawn should be scarified. Many years of practice in the private and commercial sector have shown that a combing depth of 3 millimeters is recommended.

Set the scarifier to this at the beginning and walk a few meters off the lawn. If there is a thick layer of moss, thatch and weeds on the track, no further adjustments are required.

Humus levels lawn holes

If lawn mowers and scarifiers bump across the lawn, level out the bumps with hummus. The best opportunity for the sanitation measure is after combing out the moss and weeds. Enrich the humus to a third with fine-grained sand.

Spread this mix evenly overall gaps in the lawn. Then smooth out the damaged areas and scatter lawn seed.

Sieve the light germs very thinly with sand and water with a fine spray. The use of peat has long been frowned upon in the natural home garden for this purpose, to stop the overexploitation of our valuable moorland.

Scarifying the lawn correctly

Sow the lawn after scarifying 

Are bare patches in your lawn a thorn in your side and you’re wondering when you should overseed? Lawn seeds in scarified lawns provide excellent framework conditions for rapid germination.

Scarifying removes moss, weeds, and thatch that make life difficult for young lawn seeds. How to properly sow the lawn after scarifying:

  • The best time is after scarifying between April and September
  • Fill seed into a spreader
  • Adjust the dosage according to the manufacturer’s instructions
  • Scatter lawn seed lengthwise and crosswise
  • Work in lightly with a rake and sprinkle with water

In the following four weeks, keep the scarified and overseeded lawn constantly slightly moist. During summer drought, you should blast daily. From a stalk height of about 8 cm (3 inches), mow the rehabilitated lawn back to 4 to 5 cm (1.9 inches)


Lawn reseeding without scarifying is usually doomed to failure. Moss, weeds, and leftover clippings form an all-suffocating layer on the turf. In order for lawn seeds to germinate and seedlings to take root, the felt-like bulwark must first give way.

Lawn sanding after scarifying – when and how?

If a lawn thrives on clay soil, the risk of waterlogging looms over the lawn like a sword of Damocles after every heavy downpour. By applying fine-grain sand after scarifying, you loosen compacted subsoil and create effective drainage.

Sand with a grain size of 0 to 2 mm, such as washed Rhine sand or play sand, is well suited. Spread the sand with a spreader that you set to a dosage of 5 liters per square meter(1.3 gallons per 10 SF).

Scarifying the lawn correctly

Aerate or scarify the lawn? – Differences

Scarifying scratches the surface of the turf to remove weeds, moss, and old lawn clippings. If the lawn remains sparse, a more in-depth treatment will solve the problem.

By aerating a lawn, you break up compaction up to 10 cm ( 3.9 inches) deep. In technical jargon, the freshness cure is referred to as aerating.

Motorized aerators work with hollow spoons that deeply perforate the oxygen-poor turf. Machine rental companies offer the equipment at low rental prices. You can aerate smaller lawn areas manually.

Hand fans consist of hollow-ground spikes on a rail. These are pressed into the turf using a handle with a handle and the cones of the earth are caught in a trough. Then sweep fine-grain sand into the punched holes in the lawn for drainage.

Lime only when necessary

Liming is not automatically part of the expert after-treatment of a combed lawn. Increased moss growth signals that the pH is too low and should be improved with lime. If, on the other hand, clover and other weeds are mixed in with the lawn thatch, you should check the actual pH value.
A soil test, which you can purchase at a reasonable price in garden centers and hardware stores, eliminates any remaining doubts. A pH below 5.5 signals that you should lime your lawn after scarifying.

frequently asked Questions

When can we scarify our newly laid lawn for the first time?

After two to three years at the earliest, new lawns are so well rooted that you can scarify the green area. A scarifier cannot differentiate between moss, weeds, and noble grasses. Before scarifying for the first time, please wait until the delicate stalks have taken root so deeply that they do not give way when you pull them lightly.

I would like to scarify, overseed and care for my lawn according to the lunar calendar. What should I pay particular attention to?

From our point of view, it does not make sense to look after a lawn exclusively according to the lunar calendar. Rather, a combination of local framework conditions and dates according to the lunar calendar has proven itself in everyday gardening practice. When the lunar calendar recommends a date for scarifying, the lawn should be dry and the ground thawed.

Removing moss from the lawn without scarifying – is that possible?

It is not easy to remove moss from the lawn without scarifying. It is important to deprive the moss of its livelihood in the lawn by improving the framework conditions for the noble grasses. The main causes of a moss-covered lawn are: pH value that is too low, lack of nutrients, soil compaction, waterlogging, and mowing too deep.

Why should I fertilize my lawn first and then scarify it? Isn’t that a waste of expensive lawn fertilizer?

Valuable lawn grasses have to be tough so that they don’t fall victim to the scarifier’s rotating blades. You significantly strengthen the resilience of the stalks if you fertilize a lawn first and scarify after about two weeks.

 As a further advantage, small gaps in the combed lawn close more quickly if you have applied a lawn fertilizer beforehand.

Should I scarify the lawn in the fall?

In the course of summer mowing and plant, residues accumulate between the noble grasses. This causes the lawn to become matted and the soil compacted. If moss and weeds also sprout, water, nutrients, and air can no longer reach the lawn roots.

It is therefore advisable to scarify the meadow again before winter. Here’s how to do it right:

  • Scarify the matted meadow lengthways once in August or September
  • The blades cut no deeper than 3 millimeters into the turf
  • After a week, fertilize the lawn and sprinkle repeatedly

At this time of year, the lawn in the garden requires a different nutrient composition than in spring. Instead of nitrogen and phosphorus, the focus is now on potassium. This mineral strengthens the plant cells against the stresses of winter.

In particular, the cell walls are better able to withstand the fluctuating temperatures between frost and thaw thanks to potassium.

What alternatives are there to scarifying?

Experienced gardeners scarify their lawn at least once a year if necessary. However, if you don’t want to have a sparse lawn in front of your eyes for several weeks, you can meet the problem with continuity.

 Instead of slitting the sod with knives once, the lawn is aerated after each mowing. Here’s how to do it right:

  • The lawn has not mutated into a completely mossy meadow
  • A stable, high-quality feather broom is available
  • After each mowing, break off the grass surface thoroughly with the spring broom
  • Moss and clippings that are not collected are continuously removed

If all other measures of professional lawn care are carried out in the garden, you can save yourself scarifying every year thanks to this persistence.

Since you will encounter each weed individually during this activity, you can simply cut out unwanted guests, such as dandelions and the like, with the weed cutter.


If you are willing to spend a little money, you can have your lawn scarified by a specialist. The decisive factor for calculating the costs is the size of the green area.

Experienced specialists take care of all scarifying work, including any preparatory and follow-up work. If you choose a local provider, there are no separate travel costs.

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