Scarifying the lawn correctly – Instructions – Does it make sense?

Scarifying comes from the English “vertical” and “cut”, in German “vertical” and “cutting”, in French the plow blade is called “coutre”. Scarifying means nothing other than “vertical cutting”, and that’s exactly what you do when scarifying. They cut into the lawn with a knife and to a depth of a few millimeters.

Or rather, you do that to your lawn. When you cut the lawn, always cut the roots as well. Plants really don’t like that. This assertion quickly becomes understandable when you consider how a healthy and beautiful lawn is created and how it is put together in the root area.

How does a lawn grow?

Lawn plants are grasses. Not only one grass grows on every lawn, but several, which support and complement each other in their respective properties. Most lawn seed mixtures have the same basis: a triad of perennial ryegrass and red fescue with a little meadow grass (depending on the type of lawn in different proportions and supplemented by other grasses). Perennial ryegrass grows in clumps (in clumps, clump-forming), red fescue grows in clumps and rasped (lawn-like, lawn-forming), meadow meadow-grass grows loosely rasped.

Both growth forms make a difference for the botanist. Not for the development of a beautiful lawn: A clump-forming grass develops many, mostly upright shoots close together by branching at the base. The more the growth is described as clumpy and the less as raspy, the shorter are the runners that the grass forms for propagation. In the ideal-typical clump, the young side shoots would only develop in the leaf sheaths of the mother shoot. The ideal eyrie would simply grow as an ever thicker and denser clump in one place. In the lawn-like growth form, new shoots also grow close together. However, the grasses multiply continuously to the sides by conquering the terrain via shoots or rhizomes of different lengths.

The roots of these grasses are fairly shallow under the ground. They do not know taproots for anchoring in depth. Each root now forms further roots at the base of the stem and at its foothills, these form lateral roots. In this way, a community of many grass plants on the lawn develops a very artistic structure in “constructive cooperation” – a root system in which the root of a single grass plant can reach a considerable length (red fescue: 250 meters in radius). However, as each individual grass plant spreads, this root system is often intertwined and supports each other. The competition among the grasses is conveyed so that each individual grass gets its own habitat.

This complex, coherent growth with which the grasses cover the ground is called turf. A neatly constructed and closed turf is something like the “Holy Grail of the landscape gardener”. Soil life begins under this turf on a healthy lawn. A rich soil flora, bacteria, centipedes and earthworms ensure that the balance and thus cohesion are maintained. If soil life is disturbed or if cohesion is impaired by mechanical measures, the turf can tear off. A well coherent turf is also the reason why we buy expensive rolled turf to be able to bear loads quickly. At least it already has a turf of about 2 cm thickness (for the professional area there are lawn tiles with a turf of 8 cm).

If you take a look at this growth form of a healthy and resilient lawn, it seems all the more astonishing that it is said to be beneficial for a beautiful lawn to repeatedly cut up this root cohesion.

Does a lawn have to be scarified at all?

The professionals take care of the turf on the golf course or in the football stadium, i.e. turf that must be resilient and playable in all weathers. The quality of the turf must be secondary to these requirements. The required resilience and water permeability can only be achieved if the turf base layer (the growth layer) consists largely of sand. A typical stadium turf growth layer consists of 90 percent sand and 10 percent sandy topsoil. This is an almost sterile soil with no soil life to speak of, hostile to plants and lean. Any seasoned farmer would weep if his soil looked like this. But it is easy to mow and extremely water permeable. Rain seeps away very well.

However, in order for a blade of grass to show up on such a ground at all, and then in a density that looks like lawn, specialists have to constantly give it very special care measures. And that’s where we’ve arrived: with scarifying, which replaces the careful work of the soil organisms with an attack on the lawn armed with knives, because where there is no soil life, no plant remains are broken down either. This treatment of the lawn damages it considerably, so scarifying is far from enough. Such a lawn must also be supplied with new sand and nutrients on an ongoing basis. Above all, it must be regularly reseeded.

In the private garden, however, nobody forces you to attack your lawn like Mackie Messer. An hour of “slicing the lawn” in more than strenuous manual labor may help you reduce aggression, but it will not benefit your ornamental lawn, no matter how many times you attack your lawn. They disrupt several of the functional mechanisms of a healthy turf, which you probably don’t want.

• You really don’t want every blade that lands on the lawn while mowing to contribute to the matting of the lawn. What you actually want is a healthy soil under your lawn, in which many soil organisms can break down the thatch without your intervention. A bit of loose thatch, about an inch, will appear during the breakdown process, but that’s the way it’s meant to be. This felt is important for the bonding of the turf.
• You also don’t want rainwater to simply run through the roots of your lawn into deeper layers without the roots being able to absorb enough water. You want your lawn to absorb a lot of liquid in the root area every time it rains.
• You actually don’t want the roots and the freshly sprouting stalks of your lawn plants to be badly shredded by a whole row of knives at regular intervals. Instead, you want each individual grass plant to develop as well as possible so that it can find a balance of existence with its neighbors and so that all of them form the wonderful network known as the “sward” as soon as possible.
• In fact, you don’t want a lot of weeds to settle in your lawn, because the grasses are so weakened by the constant attacks that they have no resistance to the foreign invaders.
• You don’t actually want to encourage these growths that are far from the lawn by digging up space in the lawn for them. But that is exactly what you are doing when you scarify the lawn and then use the rake to rip out everything that is just half clinging to the ground.
• You actually don’t want the plants’ respiration, which in contrast to human respiration works not via air but via light (photosynthesis), to be disturbed by your lawn care measures. But that’s exactly what you’re doing when you scarify with the idea that your lawn needs air, damaging roots and stalks in the process. The lawn plant must first repair this damage, and the metabolism suffers.

Wenn Sie all das also nicht möchten, lassen Sie Ihren Zierrasen doch um Gottes Willen einfach in Ruhe (wachsen)! Wenn Ihr Rasen angemessene Bedingungen vorfindet, können Sie sich darauf beschränken, regelmäßig und immer nur ganz wenig mit dem Rasenmäher abzuschneiden. Das bleibt dann einfach auf dem (ruhig 5 cm langen) Rasen liegen, und Ihr Rasen wird ganz von alleine immer schöner und dichter.

Vertikutieren als begleitende Pflege

Ein gesunder Rasen entsteht jedoch nur auf einem gesunden Boden, mit genügend Bodenorganismen darin, und genügend Nährstoffen. Viele Gartenböden wurden in der Vergangenheit in einer Weise behandelt, die dem Nährstoffgehalt und dem Bodenleben stark geschadet hat. Überdüngen, zu viel und zu tief Vertikutieren und vieles mehr. Hier ist also zunächst eine Bodensanierung bzw. gründliche Bodenverbesserung erforderlich, die dauert.

Dann dauert es vielleicht auch eine Weile, bis sich im Rasen das oben beschriebene Gleichgewicht einpendelt und der alte Spruch wieder gilt: Die Grasnarbe wächst alleine zum schönen, dichten Rasen. In der Zwischenzeit können Sie Ihrem Rasen helfen. Durch regelmäßiges Einharken von feinem Kompost, und auch durch Vertikutieren zu Beginn der Hauptwachstumszeit. Das stresst den Rasen zwar sehr, aber regt auch das Wurzelwachstum an. Sie müssen dann nur im oberen Bereich mit einem nicht sehr dichten Rasen rechnen. Wenn Sie es übertrieben haben, werden die betroffenen Flächen absterben.

Steriler Sportrasen gewünscht?

Vielleicht lesen Sie ja diesen Artikel, weil Sie auf Ihrem Grundstück den Rasen anlegen möchten, auf dem demnächst die Spiele der Kreisliga ausgetragen werden sollen (oder für die Pflege dieses anderswo gelegenen Rasens zuständig sind). Dann können und müssen Sie Vertikutieren, aus folgenden Gründen:

• Rasen, der immer belastbar und bespielbar sein soll, wächst auf einer sogenannten Tragschicht aus viel Sand und wenig sandigem Oberboden (90 zu 10).
• Wie diese Tragschicht aussehen muss und welchen Saatgut Sie benutzen dürfen, ist für wirklich professionelle Anwendungen in der DIN 18035-4 geregelt.
• Ein solcher Sportrasen ist sehr gut wasserdurchlässigen und sehr schnittfest, wächst aber auf einem fast sterilen Boden.
• Er wird durch Bespielen mit Stollenschuhen zusätzlich verfilzt, indem Gräser in den Boden gerammt werden, dieser Filz wird ziemlich hart.
• Da unter diesem Rasen kaum Bodenleben ist, würde sich aber noch nicht einmal der natürliche Rasenfilz ausreichend abbauen.
• Deshalb braucht er dauernd Pflege, in den nacheinander folgenden Schritten: Vertikutieren, Sand unterbringen, Nachsäen, Düngen.
• Beim Vertikutieren wird der Filz entfernt, der Sand stellt den Wasserdurchlauf wieder her und lockert den Restfilz.
• Dann schließt man die beschädigte Grasnarbe durch Nachsaat wieder und stärkt das Gras durch düngen.

Anleitung zum Vertikutieren

Ob Sie einen Sportrasen mit dem elektrischen Vertikutierer befahren oder Ihrem kleinen Rasen vor der Haustür mit einem Hand-Vertikutierer auf die Sprünge helfen, das Prinzip ist immer gleich:

• Sie fahren mit einer Messerwalze über den Rasen, die den Rasen in regelmäßigen Abständen einschneidet
• The depth is chosen depending on the purpose. In order to stimulate root growth, it is sufficient to cut open the excess felt to a depth of approx. 5 millimeters.
• If a sports turf has not been cared for and is really matted, you will usually scarify it a little deeper to restore the water permeability.
• The lawn thatch cut into pieces by scarifying must now be removed by vigorously raking it off with a sturdy rake
• It is best to scarify at the beginning of the main lawn growth, then the lawn can handle the stress best
• Before that, the lawn is cut shorter than usual, to about 3 mm. The soil should not be too wet, otherwise entire turf will remain in the rake when raking
• After scarifying, the soil is overseed and when the new seed appears, it is also fertilized.

Conclusion
If you want a really beautiful ornamental lawn that grows dense and strong without much work, scarifying is just one possible supportive measure on the way there. No true English lawn has ever seen a scarifier. This constant damage to the turf actually belongs in the professional field, in which the lawn has to meet completely different requirements than in most private gardens.