Hard Surface Cleaning

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Eradicating hard-surface tennis court moss

There’s no accounting for interests. Some people cultivate one of the 12,000+ varieties of moss for their intrinsic beauty. But if your passion is emulating Federer or Williams, tennis court moss is almost certainly a hard-to-eradicate, unsightly and potentially dangerous nuisance. Perhaps, by understanding moss and its weak points we can exploit these to find the best moss killer for tennis courts and give you more enjoyable on-court time!

The (brief) science bit

Moss is a Bryophyte – a non-vascular plant, which photosynthesises light and absorbs nutrients from the air, not from roots. Its equivalent to a normal plant’s root is called a rhizoid; this anchors moss to surfaces such as your tarmac tennis court. Moss propagates asexually and by propagating spores. During the former, a piece breaks off the moss and grows beside it; this is how clumps of moss develop. With propagation, which occurs when mosses cross-pollinate, thousands of spores develop in a capsule, which then 'explodes' – setting the spores adrift on the wind until they reach their new home….

Destination: your tennis court

When spores land on a suitably hospitable surface, they’ll start a new colony. For a surface to be hospitable, it needs to have the following characteristics:

  • A moist surface.
  • A shady area, away from direct sunlight.
  • A slightly acidic surface.
  • An undisturbed area. Moss doesn’t like heavily trafficked areas.
  • An open area to receive the floating spores.

Do you recognise any of these from your tennis court?

Astroturf Tennis court cleaning south gloucestershire

Clues to eradicating tennis court moss

Given this information, and remembering that we mustn’t damage the court surface as we clean moss away, how can we eradicate tennis court moss? I recently noticed a couple of things which suggested possible solutions.

At one property, leaves had accumulated in the corner of a moss-covered court. Expecting to find moss thriving underneath, I moved the leaves and found…no moss! Of course, even if spores got under the leaves the lack of light would make growth impossible. So, perhaps we could prevent moss by covering your court with black plastic sheeting? Or perhaps not, for though it would keep moss off, it would be unsightly and inconvenient when you fancied a game.

On another moss-afflicted tennis court, I noticed a lack of moss around the net posts. The court’s owner explained that her dogs cocked their legs at the posts. Of course! Urine is ammonia, which makes the surface less alkaline and therefore inhospitable to moss. So, maybe the answer lies in some kind of spray-on tennis court moss killer?

Closer to the ideal solution?

Armed with our new knowledge and observations, perhaps we’re getting closer to an answer – such as spraying the moss with chemicals (typically sodium chlorate). Unfortunately, experience shows that, though chemicals will kill it, the moss will eventually return! Why? Because rain washes the chemical moss treatment away and leaves a clean, hospitable place where more moss spores can settle.

By the way, I’m still seeking an alkaline moss cleaning solution that won’t harm tarmac tennis courts. In the meantime, whatever you do, NEVER use Jeyes Fluid or similar cleaners and bleaches on your court. Sure, they’ll kill moss, but like ferrous sulphate, lime and ammonia, they’ll attack and ruin your tennis court’s surface too.

Eradicating moss is a blast

Forget cumbersome covers and aggressive chemicals. Until we come up with a safe, effective moss inhibitor for artificial turf and tarmac, experience shows that the best way to remove tennis court moss is to jet wash it.

Done correctly, professional power washing digs out all the moss and spores, and washes them right off the court – without using nasty chemicals. What’s more, plenty of water helps neutralise the court’s acidity and makes it less hospitable for new moss spores. Jet washing also helps remove accumulated dust and debris. When added to tennis court moss, this helps other plant seeds to germinate, get their roots into the tarmac and start breaking up your court.

There may be 12,000 varieties of moss, but in our professional opinion there’s still only one sure-fire moss killer for tennis courts – professional jet washing.