Thomas J. Koske | 4/19/2005 10:28:31 PM
Although sports fans might not think much about how lines are painted on the field, those responsible for the job take great pride in getting their home fields to look just right, according to LSU AgCenter horticulturist Dr. Tom Koske.
Numbers and lines on turfgrass are best applied with specially formulated turf paints. These materials are not toxic to leaf blades, and they allow them to breathe. They also wear well and are usually much thicker in pigment content, so the cost is more reasonable considering what you are buying. These are often diluted to one-third or one-fourth strength.
Sometimes, though, specialty paints aren't available or affordable. In that case, Koske advises groundskeepers to use a water-based acrylic paint and to dilute it some. For football fields he recommends a 1:1 mixture. For baseball lines he recommends trying a 2:1 ratio of water to paint. It will be a "try and see" approach, since pigment density varies.
He adds, however, that some quality paints with lots of pigment may even allow a 4:1 dilution.
Gloss is important, too. "Conscientious groundskeepers do not choose a flat sheen," the horticulturist says, "because its roughness will cause it to rub off sooner."
Koske lists other features managers might not be aware of:
• Dark colors (navy, black, dark purple, etc.) will do more damage to underlying turf.
• Paints should be washable so they will stick and stay.
• Good field paints do not contain vinyl copolymers, which suffocate the grass.
• A non-mildewing agent is a desirable, though not essential, ingredient in field paints.
Koske urges teams that use a powder for marking to use ground marble dust. He doesn't recommend powdered lime products, because they cause skin irritation and change the soil chemistry in localized areas.
Once the paint is ready, a wide variety of equipment is available to apply turf paints. "Some teams still use rollers, but most use spray equipment," Koske says, explaining, "They use a compressor type or 'airless' sprayer."
He notes that others use a hand-pumped sprayer or striper, or one which applies with a fixed aerosol can of turf paint. Painting large green areas, however, is accomplished with a pesticide-type, boom spray rig. Numbers and logos are sprayed in with hand-held nozzles or wands and defined by stencils. Keeping nozzles closer to the ground gives a sharper edge.
A plant growth regulator (PGR) can be tank-mixed with the paint. This will stop the painted areas from growing much and reduces repainting frequency.
Managers must know about game boundaries and line placement. They also may have specific line widths. The sanctioning authorities will specify field size and line requirements.
"Straight lines are painted along a stretched string, but you must know whether the line is in bounds as in baseball and soccer, or out as in football," Koske points out.
For related topics, look for Gardening and Get It Growing links in the Feature section of the LSU AgCenter Web site: www.lsuagcenter.com Additional yard and garden topics are available from an extension agent in your parish LSU AgCenter office.