Moss, weeds and manure residue torpedo a dense, velvety green lawn. Dethatching clears the problems out of the way and optimizes the oxygen supply to the grass roots. Read on for a tried-and-true guide with handy tips & tricks for amateur gardeners. How to dethatch your lawn properly.
Why is scarifying useful?
When moss, weeds and rotten clippings gain the upper hand in the lawn, young lawn grasses can no longer penetrate the felt. During dethatching, the turf is scarified to a depth of a few millimeters. Rotating blades comb out the green area. The green debris remains on the lawn surface and is simply swept away. As a result, the roots of the grasses can breathe deeply again and process nutrients better.
The passionate pleas of lawn experts suggest that it is necessary to scarify a lawn every year. Before you devote yourself to the time- and energy-consuming procedure, you should critically question the relationship between effort and success. To help you make a clear decision without too much headache, we have compiled the relevant criteria for yes or no below:
|dense moss cushions||little to no moss|
|abundant weeds||scattered weed growth|
|bare patches due to lawn thatch||dense turf without gaps|
Don’t want to rely on purely visual factors before deciding between yes or no? Then take a garden rake or cultivator to hand. Loosely rake through the lawn in question at various points. If moss, weeds and old clippings get stuck in the tines, you should dethatch your lawn.
When is the best time of year to dethatch?
Basically, you can dethatch your lawn throughout the growing season. The thermometer will announce when to start. Temperatures should not drop below 10 degrees Celsius, even at night. This guideline is also valid if you want to determine in the fall, until when you can comb out a green area.
The best time of year to scarify a lawn is in the spring during March and April. In winter-warming vining regions, the window of opportunity may open as early as February. If you like your lawn freshly combed out for the winter, dethatch a second time in September or October. Again, gardeners in mild climates enjoy the privilege of being able to dethatch a lawn into November.
How often is scarifying useful?
A mossy lawn with dense weed growth should be scarified at least once a year. Spring is the best time to do this so that you can enjoy the velvety green carpet for a long time. A heavily used sports and play lawn will benefit if you comb out the green area a second time in the fall. Ornamental and shade lawns are also better prepared for the winter without the stresses of moss, weeds and cuttings.
Exclusion criteria at a glance
After a long period of rain, your lawn is so soggy that dethatching 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 pattern|
|wet lawn||destroyed lawn|
|damp lawn||grasses plucked out in places|
|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 to comb out moss and weeds or not. Despite flowers to scarify a lawn, destroys for a long time the colorful splashes of color. Scarifiers (115,00€ at Amazon*) pull everything out of the ground that they get hold of. Flower roots are not spared by the rotating blades.
As a disfigured patchwork, a lawn confronts its gardener with the decision: mill or scarify? Here you should not underestimate the regenerative capacity of noble grasses. Before you peel off a lawn and lay a new one, it is worthwhile to test it with a scarifier. Fertilizing beforehand vitalizes the last lawn grasses. After two to three weeks, comb out the green area, spread a reseed and assess the result after a few weeks.
Scarifying succeeds manually and mechanically
It is up to your horticultural decision whether to scarify a lawn by hand or by machine. A handheld unit uses rigid steel blades mounted along an axle between two wheels. By pulling the hand dethatcher through the turf while applying pressure, moss and weeds are removed. Undoubtedly, manual dethatching requires considerable effort and is primarily useful for small lawns.
Motorized scarifiers work with rotating blade rollers that slit the soil and pull out lawn thatch. The working depth can be adjusted individually. The devices are available from specialist dealers either as electric or gasoline scarifiers.
rent machines and tools
With a well-kept lawn, scarifying is not on the schedule every year. The investment in expensive machines and tools is not worthwhile for many hobby gardeners. Clever thrifty people take advantage of the offer of various hardware stores and some private providers to rent electric, gasoline and manual scarifiers at a reasonable price for a day.
Observe the right sequence
The key to success is the correct sequence of work steps. The following list provides an overview of the proper sequence for dethatching your lawn:
- 2-3 weeks before: mow lawn to 4 cm stalk height and fertilize.
- On the chosen date: mow the lawn to 2-3 cm blade height, scarify and sweep off
- After dethatching: sand and/or lime if necessary, water regularly
- 7 to 10 days after scarifying: reseed and sprinkle recognizable bare spots
- 3-4 weeks after scarifying: mow for the first time and fertilize again.
- In order for a scarified lawn to turn into an even, presentable green area, please be patient after scarifying. Let the sand, lime and reseeding do their work before mowing. The blades should have reached a height of at least 8 centimeters.
Mowing first or scarifying?
A look at this tried-and-true sequence in the workflow removes a classic stumbling block to a perfectly scarified lawn. Amateur gardeners with little experience wonder if they should mow or dethatch first. In order for the rotating blades of the scarifier or the tines of the rake to precisely target the lawn thatch at the root, mowing first clears the way for pesky moss and brazen weeds.
Step-by-step instructions – How to dethatch in an exemplary manner.
To properly dethatch a large lawn area of approximately 200 square feet or more, please allow one work day. Here’s how to proceed expertly, step by step:
- Mow the lawn to 2 to 3 cm
- Adjust the scarifier to the desired working depth
- Position the machine parallel to the edge of the lawn and start it up.
- Scarify the lawn lengthwise slowly and without stopping
- Sweep off cuttings with a rake
- Comb out and sweep the lawn in the transverse direction
- If necessary, sand and lime the lawn
- Finally, sprinkle the scarified lawn with water
The question of how deep to scarify a lawn causes worry lines on the forehead of home gardeners. Many years of residential and commercial practice have proven that a combing depth of 3 millimeters is recommended. Set the dethatcher to this in the beginning and walk a few meters of the lawn. If there is a thick layer of moss, felt and weeds on the path, no further adjustments are required.
Humus levels lawn holes
When lawn mowers and scarifiers bump over the green area, level the irregularities with humus. Best opportunity for remediation is after combing out moss and weeds. Enrich the humus to one third with fine-grained sand. Spread this mix evenly over all gaps in the lawn. Then roll the damaged areas smooth and scatter lawn seed. The light seedlings are sifted with a very thin layer of sand and watered with a fine spray. The use of peat has long been frowned upon in natural home gardens, even for this purpose, to stop the overexploitation of our valuable moorland.
Seeding the lawn after dethatching – this is how it works
Are bare patches of lawn a thorn in your side and wondering when to reseed? Lawn seeds find excellent conditions for rapid germination in a scarified lawn. Scarifying removes moss, weeds and felt that make life difficult for young lawn seeds. Here’s how to properly seed lawns after dethatching:
- The best time to seed after dethatching is between April and September.
- Fill seed into a spreader
- Adjust dosage according to manufacturer’s instructions
- Spread lawn seed lengthwise and crosswise
- Work in lightly with a rake and irrigate
In the following four weeks, keep the dethatched and reseeded lawn constantly slightly moist. In summer drought conditions, sprinkle daily. From a stalk height of about 8 centimeters, mow the rehabilitated lawn back to 4 to 5 centimeters.
Lawn reseeding without scarifying is usually doomed to failure. An all-suffocating layer forms on the turf from moss, weeds and leftover clippings. In order for lawn seeds to germinate and seedlings to take root, the felty bulwark must first give way.
Sanding the lawn after scarifying – when and how?
If a lawn thrives on clay soil, the danger of waterlogging hovers over the green area like a sword of Damocles after every heavy downpour. By applying fine-grained 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 set to a dosage of 5 liters per square meter.
Aerate or scarify the lawn? – Differences
Scarifying superficially scarifies the turf to remove weeds, moss cushions and old lawn clippings. If the lawn still remains sparse, a deeper treatment solves the problem. By aerating a lawn, you break up compaction to a depth of 10 centimeters. In technical jargon, the freshening treatment is called aerification.
Powered aerifiers use hollow spoons to deeply perforate the oxygen-deprived turf. Machine rental companies offer the equipment at a low rental price. You can aerate smaller lawns manually. Hand aerators consist of hollow ground nails on a rail. These are pushed into the turf via a handle with a stem, and the soil cones are collected in a trough. You then sweep fine-grained sand into the punched turf holes as drainage.
Liming only when necessary
Liming does not automatically count as expert aftercare of a combed-out lawn. Increased moss growth signals that the pH is too low and should be improved with the help of lime. If, on the other hand, clover and other weeds are mixed in with the lawn thatch, you should check the actual pH value. The last doubts can be cleared up with a soil test, which you can purchase at a reasonable price in garden centers and hardware stores. A pH of less than 5.5 signals that you should lime your lawn after dethatching.
Frequently asked questions
When can we dethatch our newly installed lawn for the first time?
New turf is not rooted well enough for you to scarify the green area for at least two to three years. A scarifier cannot distinguish between moss, weeds and noble grasses. Please wait with the first dethatching until the tender blades have taken root so deeply that they do not give way on a light pull.
I would like to scarify, reseed and maintain my lawn according to the lunar calendar. What should I pay special attention to?
From our point of view, it does not make sense to maintain a lawn exclusively according to the lunar calendar. Rather, a combination of local conditions and dates according to the lunar calendar has worked well in daily gardening practice. When the lunar calendar recommends a date for dethatching, the lawn should be dry and the soil thawed.
Removing moss from the lawn without scarifying – is it possible?
It is not an easy task to remove moss from the lawn without dethatching. It is necessary to remove the basis of life for moss in the lawn by improving the conditions for the noble grasses. The main causes of a mossy lawn are: too low pH, lack of nutrients, soil compaction, waterlogging and mowing too deeply.
Why should I fertilize my lawn first and then scarify it? Isn’t that a waste of expensive lawn fertilizer?
Valuable lawn grasses need to be tough so that they do not fall victim to the rotating blades of the scarifier. You will significantly strengthen the resistance of the blades if you first fertilize a lawn and then scarify it after about two weeks. As another advantage, small gaps in the combed-out lawn will close faster if you have administered a lawn fertilizer in advance.
Should I dethatch the lawn in the fall?
During the summer, mowing and plant residues accumulate between the noble grasses. In this way, the lawn becomes matted and the soil becomes compacted. If moss and weeds also sprout, water, nutrients and air can no longer reach the roots of the lawn. It is therefore recommended to scarify the lawn one more time before winter. Here’s how to do it right:
- In August or September, scarify the matted lawn one time lengthwise.
- The blades do not slice deeper than 3 millimeters into the turf
- After a week, fertilize the lawn and water it repeatedly.
At this time of year, the lawn in the garden requires a different nutrient composition than in the 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 fluctuating temperatures between freezing and thawing weather are better withstood by the cell walls thanks to potassium. Experienced lawn whisperers therefore fertilize every year with patent potash after scarifying as part of fall care.
What are the alternatives to scarifying?
Experienced gardeners scarify their lawns at least once a year if necessary. However, if you don’t want to be faced with a thinning lawn for several weeks, you can tackle the problem with continuity. Instead of slashing the sod once with knives, the lawn is aerated after each mowing. This is the right way to do it:
- The lawn has not mutated into a completely mossy meadow.
- A sturdy, high-quality spring broom is available
- After each mowing, rake the grass area thoroughly with the spring broom
- Moss and uncollected clippings are continuously removed.
Provided that all other measures of professional lawn care are carried out in the garden, thanks to this perseverance, you can save yourself from scarifying every year. Since during this activity you will meet each weed individually, simply prick out unwanted guests, such as dandelions and consorts with a weed cutter.
If you’re willing to shell out a little money, you can have your lawn dethatched by a professional. The decisive factor for calculating the costs is the size of the green area. For as little as 1.19 euros per square meter, experienced professionals will do all the scarifying work, including any preparatory and finishing work. If you choose a local provider, there are no extra travel costs.
I have 30 years of experience and i started this website to see if i could try and share my knowledge to help you.
With a degree a Horticulture BSc (Hons)
I have worked as a horticulture specialist lead gardener, garden landscaper, and of course i am a hobby gardener at home in my own garden.
Please if you have any questions leave them on the article and i will get back to you personally.