Heat Waves and Tennis Court Irrigation: Maintaining Optimum Hydration

Heat Waves and Tennis Court Irrigation: Maintaining Optimum Hydration

There is no doubt that a properly hydrated court is a more consistent court to play on and is easier to maintain. This is the reason that so many are switching to technologically-advanced, underground irrigation systems like HyQ. With HyQ, courts hydrate quickly and automatically, and only to the extent needed.  They are easy to monitor but require little actual adjustment.  There are no wet/dry cycles that courts with timed irrigation systems experience.  And there is no need to shut courts down midday for watering. All that said, many still have to manage with above-ground irrigation, so here is information to help you build a plan to keep your courts in great condition, even when temperatures are soaring.


Why does water matter?

Tennic court irrigation

It is important to understand that the surface and base layers of a Har-Tru court act as a reservoir for water.  When evaporation rates rise, water resting in the base of the court is pulled to the surface, keeping it smooth and stable during and after play.  With inadequate replenishment, from rain or manual irrigation, there will be no water to draw from, and the court surface will become dry, dusty, slippery and uneven.  Our job is to figure out a watering schedule and a maintenance regimen that allows us to keep the reservoir from drying out.


When and how much should we water?

The best time to replenish the water is overnight.  The courts are closed and evaporation rates are low.  How long to water should be determined by observing your irrigation system in action and timing how long it takes for the court to flood to the point where the water is just running off.  Use this information to schedule two to four watering cycles that allow for deep soaking water penetration (see a sample watering schedule in Chart 2). With good replenishment overnight, you should be able to get by with just one watering cycle during the day.  Make sure the daytime cycle if long enough for soaking and drying in a period of 1.0 - 1.5 hours.


Avoid too much sweeping

Sweeping prior to watering is a good routine. Sweeping without watering is not.  Every time the top layer of the court is turned over and redistributed, evaporation is accelerated.  So it is best to try to avoid sweeping unless you will be watering immediately afterwards.  The type of tool you use to sweep can also make a difference.  A heavy brush turns over more material and will cause a court to dry more quickly than a lighter one.  We recommend an Aussie Clean Sweep in place of a drag brush.  The Aussie is a drag mat that does a good job smoothing and levelling but disturbs less material.

 Aussie Clean Sweep


Use water absorption enhancers

Magnesium and Calcium Chloride are great products to supplement your above ground irrigation system (MAG & CaCl should not be used on sub-irrigated courts). Both products chemically attract water, drawing it out of the air and pulling it to the court surface. Many use Magnesium & Calcium on a weekly basis to get through hot, dry bouts of weather. An application of 45 kg per court applied with a broadcast spreader or thrown out with a shovel is all it takes. The effects of Calcium & Magnesium are temporary and only last 2-3 days so it’s best to apply them just prior to a time of heavy court use.  Be sure to water following an application to be certain the chlorides dissolve before play resumes.


Assess and experiment

Since water is such an essential ingredient for keeping your court in good shape, a sprinkler system that provides inadequate water and/or uneven distribution may be the single biggest maintenance headache a Har-Tru court owner can have. There are several ingredients to understand when designing and maintaining your watering system, namely the water pressure and volume you have and the size of your incoming water line. With this information you can begin to devise a strategy to improve water distribution and maximize the amount of water you can get on the court in a short period of time.

The data will allow you to experiment with sprinkler heads, valves and controllers that may be better for your situation. There are many old, outdated, irrigation systems out there and it may make sense to have your system evaluated by a professional. Our Consulting Services department can always inspect what you have and assist you in drawing up a plan to improve it.


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