Let’s begin by acknowledging that synthetic fields are NOT maintenance free and have more characteristics of a natural turf field then is believed. No matter what anyone says, synthetic turf does require routine maintenance. Second, infill material will gradually disappear from the field as it is carried off by players, wind, rain, snow removal, routine maintenance, equipment tires, etc., and since it is a crucial element of a synthetic field, missing infill will need to be replaced.
Replenishing infield material
Most synthetic turf sports fields lack adequate infill material (whether the infill is all crumb rubber or a rubber/sand mix). On average, an athlete or end user will carry off two to three pounds of infill material during a playing season. Without infill support, the turf fibers bend over too far under traffic and then break off prematurely. Also, ultraviolet rays from the sun are extremely damaging to synthetic fibers. By maintaining a proper amount of crumb rubber, you can help prevent the fibers from folding over, which minimizes the amount of each fiber that is exposed to the sun and reduces fiber breakdown from ultraviolet rays.
To calculate your field’s infill-replacement needs, you first need to first determine how much infill your field currently has. Measure the amount of crumb rubber in a variety of locations within the field boundaries (there are several tools you can use to this and most are easy to find; a 3-legged measuring device is recommended and your turf manufacturer can assist in where to purchase, or you can use a Starrett gauge, depth gauge or something as simple as a pen or pencil with a tape measure to determine how much infill is in the turf).
If your turf is 2-1/4 inches tall and you have less than 1-1/2 to 1-3/4 inches of infill, you need to add more and since there is no standard and each manufacturer will recommend different levels, my experience is to maintain infill to allow ¾-inch or less of exposed fibers above the infill level.
In each square foot a ¼-inch of infill is equal to approximately 0.55 pounds of crumb rubber.
Most rubber/sand infill systems will not need additional sand since sand tends to stay stable within the turf. On rare occasions, sand may be lost due to operations (snow plowing) or torrential downpours that cause flooding; in those circumstances, sand will need to be added to the mix.
Grooming the field
Grooming the field is an essential maintenance task. We highly recommend using a groomer designed specifically for synthetic turf, such as the GreensGroomer or the Wiedenmann units. When using any groomer, adjusting it so that it only lightly touches the fibers will provide the best results; do NOT lower the entire weight of the groomer onto the turf UNLESS you want to level out uneven spots or move the crumb rubber to fill an area such as a lacrosse goal crease. When “tickling” the fibers with the groomer’s brushes, the intent is to stand the fibers up to minimize their lay-over from use.
We recommend that the field be groomed every 300 to 350 hours of use; some internet articles suggest 400 to 500 or more hours, and much depends on your facility’s available manpower. At minimum, the field should be groomed several times during the highest use periods and less often during the down times (if there is such a thing).
Cleaning the field
Trash and debris are a constant nuisance. Timely removal is important to keep them from becoming ground into the infill material, causing removal problems later on.
Although largely overlooked, chewing gum on the field should be removed as soon as possible. Most chewing gums today never harden, and with the intense heat in the field, gum becomes gooey and eventually spreads across the turf surface. To remove gum, use either ice cubes or a freezing spray agent to harden the gum, chip it off and remove it.
When we deep-clean our clients’ synthetic fields, our equipment most frequently removes items such as sunflower seeds, pistachio/peanut shells, candy wrappers, cigarette butts, wire ties from nets, buttons, fabric scraps, cleats, bobby pins, jewelry, screws, nails, staples, paper clips and rocks (from broken stone bags that are used to weigh down goals and equipment). These items—plus dust, dirt, pollen, body skin cells, human hair, leaves and pine needles—can end up embedded in synthetic fields, where they remain for much of the life of the field.
It’s astounding, actually, how quickly debris can accumulate, unseen, on a synthetic field, causing several problems. Such debris can create safety hazards for the athletes (particularly sharp metal items), abrade the synthetic grass fibers and degrade the crumb rubber (which, in turn, increases the field’s hardness), reduce water infiltration by clogging drainage pores, and develop an organic layer that is conducive to the proliferation of bacteria, mold, moss, fungi and insects, as well as the germination of weed seeds.
Special deep-cleaning equipment with HEPA-filter vacuums can remove this type of debris from within the turf. Rain, snow, sleet and hosing will not wash it out.
Invariably, field managers ask if synthetic fields need to be disinfected. For the best answer, my suggestion is to review the research pages of Dr. Andrew McNitt at Penn State (http://cropsoil.psu.edu/ssrc/sportsturf-scoop).
Weeds can exist and thrive in synthetic turf, especially if the field is not deep-cleaned regularly enough to prevent an organic layer from developing. Also, if your turf is surrounded by bermudagrass or any other creeping grass variety, be prepared because the stolons and rhizomes of such grasses tend to seek their way into and under the synthetic turf. Synthetic-field surfaces reach optimal growing temperatures before the surrounding turf does, providing a perfect greenhouse effect for creeping varieties to spread. After they start spreading beneath the synthetic field, they will find the drainage holes and send their shoots upwards for the sunlight.
The resulting sewing-machine effect makes removal of creeping grasses quite difficult, and in most cases, they will need to be chemically treated (as approved by the turf manufacturer) to kill them off. The simplest solution is to prevent them from growing in the first place; this can be done either by pulling them when young, spraying Round Up or an organic product designed to kill young weeds and grass, and then being vigilant so that you can act quickly if you discover an encroachment.
Patching worn areas
Pay particular attention to maintaining adequate infill material in heavy wear areas. Synthetic fields wear just like natural turf, except that you can’t grow the fibers back in once they are gone.
For instance, lacrosse players can destroy a goal crease in as little as one year if the turf is not maintained. The infill material gradually gets kicked or shuffled out, and then the fibers take a beating and break off quickly without the support of the infill material. Before you know it, you’re left with a big black area (which is the backing for the synthetic turf), and now it’s time to patch it. You could replace the area with either a piece saved from the initial installation, or you could cut a piece from outside the playing area so that it matches in color and type. Still, though, it won’t be a perfect match because the fibers in the patch piece will not have had as much wear (so the “nap” won’t be the same).
In addition, to make a patch in a synthetic field, you will need special materials, and your local home improvement or hardware store does not carry them. Don’t use Gorilla glue, “liquid nails,” styrene bonding agents, and/or drywall screws or framing nails for repairs, since they are not designed for synthetic turf and may later become a liability nightmare. Instead, contact the manufacturer or a reputable service company to handle making the patch.
Painting the field
Painting may or may not be needed on these fields, depending on whether or not the painted areas (lines, logos, etc.) were inlaid during installation. If you need to paint, use only a paint product that is approved for synthetic turf. It seems that every year a new synthetic turf paint debuts, so do your homework; look at each company’s history, and get recommendations from other turf managers with synthetic fields. In case you later need to remove the paint, ask the supplier whether it can be done, how it is done, what it will cost, how long it will take and whether you will need special equipment and chemicals. Also ask if the product has been endorsed by any synthetic turf manufacturers and whether your turf’s manufacturer is one of them.
If you have to paint, try to do so at times other than during the heat of the day. Also, removing lines works much best at night or early in the morning (when the turf is the coolest); otherwise, the chemicals will evaporate long before they start to work, and this will only cost you more time and materials.
Damping down static
Static on a synthetic field is common and can increase with humidity and (sometimes) field age. If you need to combat this, you can do so with one of several household products. Liquid Tide detergent and liquid fabric softener both work well when sprayed on the turf.
Finally, unlike with natural turf, we can’t see what is happening underneath the surface of a synthetic field. ASTM has recommended that synthetic fields be tested annually to determine their hardness in G force (better known as Gmax). Although some turf managers do not believe this is necessary, I can assure you that it is an important tool, much like soil tests with natural field (see page 12 in this issue for more on this).
If you don’t test every year, you have no data to determine what has occurred over time.
If properly maintained, a synthetic sports field will provide years of use and play for all users. Just be aware that they do require regular care. If you have a concern, don’t hesitate to ask a peer or your contractor for an answer; doing so can keep you from making a mistake that could significantly shorten the life of your field.
Jim Cornelius, CSFM, is manager of the Pro Services Division of Fisher & Son Co., Exton, PA, www.fisherandson.com.