I have received several questions lately about field painting. One in particular inquired about the use of paint for field lines and logos and the possibility of the darker colors (red, blue) causing more turfgrass injury than lighter colors.
Most field paint materials these days are water based acrylics and not harmful to the players. These products are made specifically for sports field use and are far superior to, and less injurious than, anything that can be picked up at a hardware store.
Picture 1: Field lines and logos on a football field are a big part of the manager's preparation. On some sports fields, like MLS or international soccer, logos are prohibited from the official play area.
Products like powdered lime, used a lot in the past, have been found to cause skin burns on players. In fact, a goal-keeper in Britain has just been awarded $50,000 in damages for injuries incurred during his soccer career. Powdered products used now, on areas like baseball skins, are made from ground marble dust.
While today's paints would appear to be harmless to players, continuous use of paints during the season will invariable lead to grass injury or death. There is a possibility that the darker colors, particularly red, filter out the spectrum of light needed for photosynthesis but Dr Jim Metzger, Professor of plant physiology at Ohio State, thinks there is more to it. "In thinking about it, I guess I could not come up with a reason based on selective absorption of light that would explain why red paint would be any more harmful than other colors. Certainly, if you used blue paint that too should have a detrimental effect on photosynthesis, since that would remove red light. My best guess as to what is going on is that the red paint has something in it that is phytotoxic and is not present, or present in low quantities in other paints".
As a brief guideline, turfgrass injury may be reduced by (1) using equipment that does not heavily coat the grass blade. Four-inch rollers can apply excess paint if not used carefully, as can aerosols. Airless or walk-behind equipment may apply less (2) painting the field as near to game day as possible (3) using lighter colors.
Brian Gimbel, superintendent of athletic fields at OSU, changed from red paint to white and gray for the Buckeye's football field logos because he wanted to minimalize grass toxicity.
Picture 2: Brian made the change so that the block color is white and the red only acts as a logo border.
Another useful tool in field painting may be the use of trinexapac ethyl (Primo). Mixed at 1oz Primo/1000ft2 this may slow down turfgrass growth, thus making the painting material more efficient. To date, there is very little technical data on the use of this product in a field painting mix.
Authors: Pam Sherratt
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