Spring maintenance of clay tennis courts is not rocket science with many secrets to uncover. With the right tools and the necessary background knowledge, it can be easily accomplished.
The tennis court in winter
Two essential things happen to a brick dust tennis court in winter.
- The substrate dries out
- The brick dust covering loses its compaction and becomes loosened due to frost exposure in winter.
The first point, in particular, sounds paradoxical. While it is indeed cold, the ground still dries out to deeper layers. Precipitation, frost, and snow then only accumulate in the brick dust layer, softening it. The underlying lava, however, dries out and loses moisture. For a firm tennis court after spring maintenance, the moisture balance in the lava layer must also be restored.
Especially in years with a very dry start to the year with little rainfall in March and April, it can be observed that the tennis courts remain soft for longer, comparable to a sponge, but the problem is actually the lack of water exchange between the layers.
It takes some courage to flood soft tennis courts so that the water can penetrate to deeper layers. Simply adding small amounts of water to the surface won't solve the problem, as the water remains trapped in the clay surface, keeping it soft. The water must penetrate through the clay down to the lava and restore the moisture balance throughout the entire clay surface; only then will the tennis court become truly hard again.
The second point, however, is easier to understand. The loosened layer of brick dust needs to settle again. This is essentially achieved through water and sunlight. Rolling is helpful in this process, but not strictly necessary with sufficient time and effort.
The use of heavy rollers weighing more than approximately 600 kg on the tennis court is not recommended. While these may accelerate hardening, the compaction is too great for the brick dust material. If the court loses moisture again, cracks can form in the surface, similar to a dried-up riverbed.
If the lava layer is already mixed with fine brick dust, this can lead to the formation of hardened layers in the brick dust cover, which then do not allow a continuous bond of the entire brick dust cover.
If the connection between the lava and brick dust is still open and permeable because the tennis court is relatively new, then fine brick dust can be pressed into the lava layer and destroy precisely this permeability between the layers. The result would be a much shorter lifespan for the tennis court before it needs to be renovated.