We asked some turf managers and equipment manufacturers for advice on maintaining the infill on synthetic turf fields.

Advice on maintaining the infill on your synthetic field

We asked some turf managers and equipment manufacturers for advice on maintaining the infill on synthetic turf fields. Our panel includes: Darian Daily, Sports Field Manager, Cincinnati Bengals; Jon Dewitt, CSFM, Athletic Field Manager, Georgia Tech; Paul Hollis, Executive Vice President, Redexim North America; Tom Lober, Director of New Business Development, Noland Sports Turf; Abby McNeal, CSFM, Director of Turf Management, Wake Forest University; Jason Mueller, Grounds Manager, Kirkwood (MO) School District; Ronn Ponath, President/Owner, Kromer Company; Doug Vescio, CEO/President, Vescio’s SportsFields; Will Wolverton, Manager, Wiedenmann North America; and John Wright, Director of Fields, Seattle Seahawks.


How often do you recommend adding infill material? 

Daily: Only when needed. I would suggest getting an infill depth measuring device and monitoring the infill depth throughout the year. In my experience, your infill depth will drop after the first year of installation due to the field “settling in,” which is normal. Once you get your infill depth back to the manufacturer’s recommended depth (each company’s recommendations are different), monitor the field and when your average infill depth gets below recommended threshold, call your manufacturer for their recommendation. If it is recommended to install more infill, have a professional infill installer apply the infill. One thing I have learned, you don’t need to apply much rubber to bring your numbers back into spec. Installers have methods of getting the infill down into the system for a safe and playable field more quickly.

Hollis: The infill material provides a cushioning effect; the more infill, the more cushioning. Playing surface hardness levels, or Gmax ratings, are almost always associated with low infill levels. It is not that the infill material is compacting like the soil does on natural turf fields. Instead, the infill is actually being removed or displaced on fields over time, in a variety of ways. The result is less infill in the field and increased surface hardness. In order to prevent this, infill levels should be measured regularly and compared to the infill depth recommendations provided by the field manufacturer. When infill levels drop below the manufacturer’s recommended range, additional rubber should be added.

Mueller: Our field is about 4 years old, and we monitor it regularly with an infill depth gauge. We have not had noticed a decrease in our infill depth, and the depth is consistent throughout the field. This is probably due to our regular grooming schedule. Also, our turf is Astroturf 3Di, and has a thatch layer incorporated into the fibers that reduces the movement of the infill.

McNeal: As often as the field needs it per your observation and manufacturer’s recommendation. Sports turf managers have to be diligent about monitoring the infill levels as the field is used; higher use fields may require more frequent additions of rubber infill mix. On our baseball field we add material in our higher traffic areas (batters boxes and base areas) almost every other day during our season. If we do not monitor these areas closely then we can have fiber wear sooner then anticipated.

Lober: The end user should have a system to chart the areas that tend to have infill movement due to high activity. For example the penalty kick line in soccer gets used heavily during practice where several kids will line up and go one after another. Corner kicks, goal mouth areas for soccer and lacrosse, and extra-point kicks for football are also critical areas. The growing application of turf for baseball fields makes sliding into second, third and home the areas that get infill movement more than any other application. 

How do you check the infill depth? This is easy and can be done by using a depth meter that can be purchased for as much as $250 or there are other companies that make depth testers for rubber track surfaces that are around $20. These tools are reasonably accurate because testing a rubber track surface requires a fine tolerance. 

The infill should be ~1/2″-3/4″ below the tips of the blade so a 2-1/2″ system should have a minimum of 1-3/4″ of infill. Not sure what height system you have? Go along the edge of the field and pull a bundle of blades and measure them. Charting the areas that require regular maintenance is something that should be done often but adding large amounts of infill should generally not be necessary for the first 3-5 years. Spreading bags of rubber and brushing the field to distribute it should be done by professional turf installers but can be done by facility maintenance staff if they are up to handling the task of moving and spreading supersacks of rubber. For example each pound of rubber equals about 1/2″ of infill per square foot. If an 80,000 square foot field is low by an average of 1/4″ then it would take approximately 1/2 pound of rubber per square foot or 40,000 pounds, which is 20 supersacks. I generally don’t recommend trying to put more then 6-10 sacks of rubber in at any one time unless the field is extremely low and requires more infill. A good practice would be to add 3-4 bags in years 4, 6 & 8. 

Dewitt: Never have had to; on my old rug the fibers were completely worn away and existing crumb was right on the surface! My new rug doesn’t get used a whole lot and it’s indoors so I haven’t had to add anything since it was installed in summer 2010.

Vescio: First and foremost the field should be filled to appropriate levels (according to specifications). The field should be checked in its entirety at least once per year. Typically a Gmax report will indicate the levels of infill. Through the Gmax report or at a minimum a yearly check will help establish the need for additional infill. More attention will be needed in small yet high traffic areas such as a soccer goal or football place kicking. These areas should be checked before use for tears, wear, and low infill.

Ponath: This depends upon several factors. With fields that have not had regular maintenance the infilling is usually done when the field shows a lack of infill and matted and entwined fibers and becomes less safe and playable. This is typically an after the fact approach and also has safety issues. Consequently more infill is needed immediately.

What is the most efficient way to re-distribute or even out the infill? 

Wolverton: Grooming the field is the most common and practical way to re-distribute the infill. This should be performed frequently based on the recommendations of the manufacturer.  Other methods help such as using a sweeper that brings some of the infill material into the sweeper, separates the infill from the debris, and evenly redistributes the infill back on to the playing surface.

Wright: Brush/tine groom multiple directions; add fill using topdresser best suited for quantity to be distributed/time-frame available; integrate added fill into system using Lay-Mor type front mounted brush.

Daily: I have seen a regular topdresser used to distribute the rubber evenly. In most cases a GreensGroomer or Sweep-n-Fill type brooms are used to work the infill in. In extreme cases, I have seen a Lay-Mor power broom being used. I would not recommend the use of a Lay-Mor unless it is use by a professional installer. A Lay-Mor will destroy a field VERY quickly if not used correctly.

Ponath: Regular conditioning grooming and finish grooming, which is a two-step process using specific tools designed for synthetic fields will redistribute the infill, decompact the fibers, and remove metal objects in one pass. The finish grooming process helps in reducing the static electricity and helps the infill to position it to support the fibers so that they stand up properly.  This improves the appearance and extends the life of the fibers. This also means that less infill will be needed.

Hollis: Brush the infill into the turf by lightly agitating the fibers back and forth using a simple stiff drag brush.

Vescio: The size of the area to refill will determine the method and the type of equipment. In large areas topdressing with a drop spreader or broadcast spreader is the easiest and most commonly used equipment.

In small areas such as a soccer goal or football place kicking, softball and baseball wear areas such as plate and pitching areas, as well as the sliding areas, redistribution of infill can be done by hand or a small push spreader. Careful consideration should be taken in these areas to simply not dump infill but to apply evenly.

Prior to any re-infill I would recommend the following steps:

Cleaning and removing any debris. There is equipment that is available on the market for so called “deep cleaning” that allows removal of the existing debris to a depth of 1/4″ or so. At the very least a tag along sweeper should be used to remove foreign particles.

After the “cleaning” and before adding additional infill brooming or sweeping the field with typical field groomer should be done to help the turf fibers stand up. In some cases a “power sweeper” may be necessary to aid in standing the fibers. This should be done by the synthetic turf provider or contractor.

In smaller high traffic areas such as soccer goal or football place kicking, softball and baseball wear areas such as plate and pitching areas, as well as the sliding areas standing up the fibers can be done with a medium to soft push broom or a hand held gas powered brush.

Make sure that the environmental conditions are good for installing the infill. Dry and non-windy days are best. 

Mueller: We use a John Deere Gator to pull a Redexim Verti-Groom. Between gym classes, band practice, soccer or football practice and games, and nightly rentals our field can see up to 10 hours of play in one day. To reduce compaction and to keep the infill evenly distributed we groom as often as once per week during periods of heavy use.

Dewitt: Don’t let it get too bad on you in the first place. If you have some really bad pockets from drills or kickers repeatedly using the same area use a power broom to heavily work those spots; otherwise a simple GreensGroomer drag behind brush has been sufficient for us. We drag about once per week and do a heavy cleaning/brooming annually.

McNeal: If it is a smaller area then we use a push broom to level out the infill or a metal tine leaf rake turned over. If it is a larger area we will use a drag over the area then the groomer and possibly the drag again. The drag is made from left over turf stapled around a wooden frame (for weight).

Lober: A push broom is the most common way but the rubber tends to fly up in the air and land back in the same spot so I recommend a two man process of push broom and blower which works very well for small areas. They can also use a small power broom. Other than that the proper use of the drag brush is the best way to make sure the field has a consistent level of infill.

 What steps should be taken to prolong the life of a field, e.g., reducing fiber wear, etc.?

Daily: We constantly drag and groom our field to keep the fibers standing up. We monitor our infill depths to insure the proper amount of infill is in the system to help the fibers stay standing up. Lastly we have the Coaches constantly moving around just as we do for our natural grass fields. It’s not much, put just enough to spread the wear out.

Hollis: Regularly scheduled maintenance consisting of: brushing or grooming the fibers, adding infill when needed, raking the existing infill that has settled to loosen the infill and prevent compaction, as well as, an annual deep cleaning should be considered when trying to extend the life of a synthetic playing field.

Mueller: We communicate with our athletic director to rotate use of the field for PE classes and practices. This is especially important for reoccurring drills, or where home plate is thrown down for PE softball. We try to match or grooming schedule to coincide with the amount of play. Our groomer has nylon brushes, and metal tines. We limit the use and the depth of the metal tines to reduce wear on the turf. We sweep our field with a Redexim Verti-Top 3 – 4 times per year. This is scheduled to coincide with periods of heavier debris; fall leaves, spring pollen, female sports (hair in turf). This debris could mix with the infill causing drainage and compaction issues.
McNeal: We groom it before each event. Monitor weekly and remove any debris (trash, leaves, etc.) off of the field. Yearly I have an outside contractor perform a deeper more through clean, Gmax testing, and independent evaluation. This allows me to see if we have missed something with our field checks. I try to communicate to our coaches the importance of moving drills and activities around to reduce “wear patterns” with some coaches I have success with others not so much. We monitor each field and adjust our program as needed, just like a natural grass field.
Lober: A very good way to prolong the life of the field is to properly decompact the field and groom it with a machine that has vacuum filtration capacity. This keeps the field from compacting and reduces the amount of dirt and debris that will settle to the bottom of the turf and reduce the drain rate. When the field does not drain properly water tends to puddle and then more dirt and debris will travel to the low spots and cause more compaction that compounds the issue. In the first 2 years of a field it is not necessary but after that a regular annual maintenance from an STC approved system should be the recommendation.

I have been doing turf maintenance with the SMG Sportchamp for 6 years now and recommend that in years 3, 4 & 5 a standard groom should be performed, after that a deep clean groom should be performed once or twice a year from year 6 on. The benefits of this are that the field is cleaned and dirt is removed to allow for proper drainage and reduced compaction. This makes the field safer by reducing the Gmax rating and also helps remove debris from the infill which can then be a better product to reuse when the field is replaced around years 10-12.

The best way to reduce fiber wear is to keep the infill up to the proper height. Having a good understanding of the difference between slit-film and mono-filament is also important.  Excessive brushing of slit-film can cause it to become wire fine and abrasive. Excessive brushing of mono-filament can cause blade release and reduce the tuft bind later in the life of the field.

Wright: Treat the surface as if it is natural turf by limiting vehicle traffic except when necessary; require vehicles to have turf-type tires; use protective flooring/plywood when non-turf friendly vehicle traffic is necessary; and prohibit food, drink and glassware on unprotected turf.

Use flooring protection system for non-sporting events and events with high volume/concentration of foot traffic. Always use an impervious layer of some sort (visqueen) beneath protection systems when hosting dirt shows, i.e. Supercross, Monster Jam, sod-overs.

Vescio: Education; it is critical that the client understands the limitations of the synthetic turf and the intent for which the turf was installed. 

Provide the client with guidelines for usage (do’s and the don’ts).

Rotation of areas; try to avoid practicing repetitive drills or usage in the same areas.

Wearing footwear that is recommended for the synthetic turf.

Inspecting infill levels monthly. Note: High traffic areas should be monitored weekly or after heavy usage and these areas should be replenished more frequently as needed depending on the use.)

While maintenance logs may not help prolong the life of the field, they may help the client if a wear or warranty issue should arise. Furthermore it will provide vital information for the synthetic turf manufacturer and contractor for what future clients can expect. Just like a vehicle warranty use and years don’t always equate to longevity.

Site visits by the contractor to the client’s site to help with evaluations and use as well as checking maintenance logs.

There is some specialty equipment in the market place available that will remove the existing infill material while producing very little disturbance and fibulation to the existing fibers. The existing infill can then be reintroduced, redistributed back evenly over the field along with additional infill needed to replenish the field. This may also help relieve compaction and lower Gmax levels.

Maintaining proper infill heights

Ponath: Maintaining the life of the field also means that less infill will be needed. If the tools and processes I’ve mentioned previously are used then the results are safer fields, playable fields and attractive fields. The final benefit is that these best practices also prolong the life of the synthetic turf which provides for a better return on investment. The frequency of this process is determined by the hours of usage on the field. The type of field whether for a specific sport or a professional, amateur, or general purpose will require different frequencies and intensities. Other factors such as sun and shade, weather, indoor and outdoor must be also considered.

Wolverton: Routine maintenance which consists of grooming and sweeping. It is important to redistribute the infill and stand your fibers vertically to reduce the breakage of fibers when they are lying down. Another important practice is to maintain proper drainage by cleaning your field periodically to remove dirt and debris.