Har-Tru Maintenance Guide (above ground, sprinkler-irrigated courts)

Keep your clay court in peak playing condition. Here’s everything you need to know about taking care of your above-ground, sprinkler-irrigated courts.

Daily Clay Court Maintenance

•  After play and before watering, brush the surface using a drag broom and clean the tapes using a line broom to smooth out and level the court surface.

•  Water the court thoroughly and uniformly to keep the court stable and to eliminate dust.

•  Roll the surface as needed, particularly on new courts. This ensures a firmer, faster court, with less granular build-up and erosion, improved moisture retention and faster drying time.

As-Needed Clay Court Maintenance


A sprinkler irrigated Har-Tru tennis court will develop depressions or low areas over time in certain high play areas, like baselines and service boxes. These depressions/low areas will be evident because water will stand in these areas longer after watering or rain. Running a string line over the court will also highlight low areas. These low areas will need to be patched.

To patch a low area, follow these steps:

  • Scarify the low area with a lute or other scarifying equipment to rough up the surface - this helps the new Har-Tru material to bind and adhere to the existing court.
  • Spread new Har-Tru material into the low area.
  • Level Har-Tru material with a straight-edge (ladder or flat side of a lute).
  • Hand water and roll the low area.
  • You may need to repeat the process if the low area is particularly deep.

Removing "Dead" Material

Daily play and watering will cause some of the larger Har-Tru granules to work themselves to the surface. These larger granules provide some ideal sliding surface material to the court and are good in small amounts. However, large quantities of large granules - known as "dead" material - can cause bad bounces and inhibit playability. These large granules are grayer in color and can accumulate in certain areas, particularly near the net and baselines.

To control "dead" material, simply use the flat edge of a lute to scrape the material into piles and remove from the court. Take care not to scrape into the regular court surface when removing the "dead" material.

Top Dressing

Sprinkler-irrigated Har-Tru courts will lose material over time due to the effects of watering, wind, rain, and play. Sprinkler-irrigated Har-Tru courts in most regions of the country will lose 2-3 tons per year (50-75, 80 lb. bags). Sprinkler-irrigated courts in Florida lose 4-5 tons per year (100-125, 80 lb. bags) due to more rain and year-round play.

In order to properly maintain a Har-Tru court, they must be top dressed on an annual basis. To top dress, follow these steps:

  • Before top dressing, be sure the court is completely dry.
  • Scarify the entire court surface using a tow scarifier, Court Devil, or lute
  • Patch low areas (see above).
  • Apply court surfacing material using a spreader.
  • Level the material using a straight edge, usually a ladder.
  • Hand water and roll the court.

Top Dressing Tips

  • You can either top dress using a small amount of material (8 bags per court) on a monthly basis or top dress using a large amount of material (50-75 bags per court) once per year.
  • If you are going to add more than 25, 80 lb. bags at one time, you may also need to remove and replace the line tapes, as more than 25, 80 lb. bags may bury the lines.

Long-Term Maintenance and Upkeep

Har-Tru courts require 1" of Har-Tru surface material for optimum playability, court stability, and moisture retention. For this reason, all new sprinkler-irrigated Har-Tru courts are built with +/- 40 tons (1,000, 80 lb. bags) of Har-Tru surfacing material. Each new Har-Tru court is also built with a 1" in 30' slope to ensure adequate rainwater drainage. This means that a new single court will slope 2" if it is sloped from side-to-side or 4" if it is sloped end-to-end.

Sprinkler irrigation, rain, wind and play will cause Har-Tru material to regularly wash off the court and to migrate (or shift) from the high side of the court to the low side of the court. Over time, your Har-Tru court will lose the ideal surface depth of 1" and the slope of the court will begin to flatten out. These changes will cause the court to retain less moisture, shift under rolling and play, and drain poorly, resulting in less than optimum (possibly even dangerous) playing conditions. Consequently, sprinkler-irrigated Har-Tru courts should receive a "laser-tapered" resurfacing every 4-5 years.

In a "laser-tapered" resurfacing, laser-guided grading equipment is used to remove excess material at the low end of the court and add new material at the high end of the court to restore the proper court slope. Fast-Dry Courts, Inc. was one of the first companies in the United States to utilize this revolutionary technique to restore Har-Tru courts to a like-new condition.