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"Green Clay" – How clay courts can quickly become natural grass pitches
Clay courts are to the greatest possible extent obsolete. Although held in high regard by communities and sports facility operators due their nearly unlimited life expectancy, low maintenance outlay and relatively high capacity for utilisation, most of today's users have finally written them off. Clay was never a preferred playing surface and now, as a greater range of alternative surfaces is available, football clubs above all are under pressure to change to something new. This has resulted in many places in the installation of above all artificial turf and hybrid grass pitches. Not necessarily a low-cost venture – conversion costs start at around Euro 350,000 and are usually in excess of Euro 500,000 – and due to a lack of community funds, in many cases clubs must share a part of the financial burden.
Low-cost alternatives are very welcome when funding is tight; and this causes a method to be repeatedly focussed on which, compared to conventional conversion projects with natural, hybrid or artificial turf pitches, is considerably less expensive: So-called "green clay". This renovation method is not a new development, but has been well known for more than 20 years. It involves mixing the existing clay surface with around 500 t of sand and substrates before sowing a sport-grass turf on this new surface after treating it with fertiliser. This sounds very simple and is actually not particularly difficult to carry out in practice. Important prerequisites however, are that the existing clay surface is suitable for this kind of conversion and that there is a functional drainage and irrigation system in place. Conversion costs including installation of an artificial rain system are usually around 80,000 – 130,000 Euro, although if the draining system needs subsequent improvement work, the costs can quickly increase by more than 100,000 Euro. Despite this, these conversion costs are still significantly lower than for other conversion alternatives.
Given that "green clay" is a viable alternative from a cost point of view, it does differ from a classic natural grass pitch with regard to play behaviour. As the sediment layer of the clay pitch is still there under the surface, these pitches are significantly harder than conventional natural grass pitches. The developers of "green clay" consider this to ensure a more hard-wearing surface as the grass roots find more hold in the sediment layer. This should also improve the ball rolling behaviour while maintaining the feel of a natural grass surface. It is expected that more than 800 hours of use each year are possible although around 600 - 700 hours should be taken for planning purposes. The conversion time is relatively short. As a rule, play should be possible on the new surface after only a few months although it depends on the weather conditions how well and quickly the grass grows.
Like any other natural grass turf, the new sports surface then requires good and regular care and maintenance costs are higher than those for an artificial turf pitch. Depending on the weather, use of the pitch can also be limited, especially in winter. It is better not to carry out some training exercises, above all endurance training, on the natural grass pitch and areas of heavy use such as the centre of the pitch should be allowed to recuperate between matches. As already mentioned, annual use is around 700 hours. If much higher utilisation is required, an artificial turf or even an unpopular hard surface will be required.
In conclusion it should be said that conversion to "green clay" can definitely provide an alternative to an artificial or hybrid grass pitch. The conversion costs are significantly less expensive and the natural grass has advantages from a playing point of view. However, a clearly lower number of hours of use (compared to artificial turf) and limitations due to weather conditions must be expected and reasonable maintenance must be guaranteed.
Picture: SSV Overrath 1919 e.V.