The characteristics of clay courts in tennis

Clay is a coating used in tennis and other sports with earth pitches.

We can imagine a clay court as a layer cake, made of 5 layers with a total thickness of around 80 cm. For the very first layer starting at the bottom, place big pebbles followed by crushed pebbles, over a thickness of 40 to 60 cm. Just above that, add some clinker (a residue of coal, a carbonaceous rock) over 7 to 8 cm. For the next-to-last layer, you need crushed limestone (grit) over 6 to 7 cm. Finally, sprinkle it all with 2 mm of red brick. This last layer, so unique to clay courts, concludes this magnificent layer cake of clay.

In order to not harden and to retain its flexibility, the clay must stay moist. That's why it is watered very frequently (at least once a day in summer). This surface requires a very significant amount of water and maintenance, which makes it expensive and not very practical for tennis clubs.

So, who had the brilliant idea of mixing these materials to create such a unique surface? It all started in the 1880s in Cannes, France. When two British players, the Renshaw brothers, realised that grass tennis courts weren't well-suited to summer conditions in the South of France, they decided to cover them with a red powder from ground-up terra cotta pots from Vallauris (a Provençal village specialising in the production of artisanal terra cotta). The legendary clay court was born, and then spread throughout Europe. It was primarily developed in France and took on a new dimension in the 1930s in Paris.

One of the first tennis tournaments to adopt a clay court was the French Open, now known as Roland Garros™. Created in 1891, the tournament was first played on cement courts, until 1928, when the surface was replaced by clay. Since then, Roland Garros™ has become the most prestigious tournament in the world, welcoming the world's best tennis players each year and thus shining a spotlight on this legendary court surface.

Clay is considered to be a slow, slippery surface. It is unique for tennis players and requires some adjustments for better performance:

▪️ Clay slows down the ball: the surface absorbs a lot of the ball's speed, which makes strokes slower. So players need to be ready to adapt by adjusting the timing of their strokes.

▪️ The surface is slippery: Due to the presence of clay dust on the surface, players should be able to use sliding techniques to reach the ball. Footwork is less important than on other surfaces. For players unused to the surface, it can be hard to adapt. But experienced players can use it to their advantage to create winning angles and strokes.

▪️ Balls bounce higher and have more spin on their bounce: Since the surface absorbs part of the ball's speed, balls bounce higher on clay. That is called the coefficient of restitution. As an example, a ball falling from 1.8 m will bounce up about 1.3 m on a clay court and 1 m on grass.
The ball will also adhere for longer on the ground and thus take on more of the desired spin than on other surfaces. This coating helps promote topspin, for example. This is called the coefficient of friction. It means that players need to be ready to play higher, more defensive shots. Not so easy for those with a more aggressive play style.

▪️ Points are often longer: Due to the slowness of the surface, points on clay courts tend to be longer and more physical. Players need to be in good shape to perform on that surface.

Adapting to clay courts is essential for professional players. This is why there are specific workouts that take place as clay court season approaches. Players can also participate in a number of tournaments on clay: Estoril and Monte Carlo in early April, Barcelona and Munich in mid-April, Madrid in late April, Rome in mid-May, followed by Roland Garros™ in late May/early June.

Most tournaments take place on surfaces other than clay. They all have their own characteristics, requiring adaptation and a group of specific technical skills that players must develop. 

↪ Grass
The oldest and least democratised court surface is grass. This surface speeds up the ball and leads to a fast game. The flagship tournament on grass is a Grand Slam tournament played in England: Wimbledon. To participate, professional players must wear only white or risk paying a fine. The world's oldest tennis tournament respects tradition.

↪ Resin
In competition, tennis is frequently played on resin (a blend of rubber and asphalt). Two of the three Grand Slams are fought on this surface: the US Open and the Australian Open. It's the fastest tennis court surface, allowing for a dynamic play style oriented towards offensive play and with faster volleys.

↪ Concrete
Concrete, also called "quick" because of the speed of play, is the most widespread surface because it is the most durable and cost-effective. Concrete easily absorbs moisture and rain, making it very practical for outdoor courts. Good serves and offensive play are helped by this type of fast court.

There are also other surfaces such as carpet, artificial clay, or even parquet. Every player has their own preferences when it comes to court surface.