Turfgrass leaves, stems and stolons growing horizontally across the playing surface can influence play by creating grain. In severe instances, grain can “grab” the clubhead as it strikes the turf and alter shots. Golf balls roll faster down the grain and slower going into the grain. Clubheads will skip or glide through the turf when hitting a shot with the grain but can grab or slow down when hitting into the grain. Some golfers even argue that hitting an iron shot into the grain may injure their wrist! Chip shots and pitch shots around the green can be especially challenging when hitting into the grain. The more aggressive the grain, the more difficult the shot may be – especially in wet conditions.
Grain tends to grow in the direction of water moving downhill, but not always. The truth about grain is that it can grow in many different directions and does not follow the setting sun. Grain can also develop from repetitive mowing patterns, especially in bermudagrass or bentgrass fairways. Switching the mowing pattern is a clear way to help mitigate grain and an important strategy should your turf have excessive grain. For many years, the primary recommendation to mitigate grain was a combination of vertical mowing and brushing. While these tactics are effective, if the grain is severe these strategies may take several years to significantly improve the situation.
I have seen several more-aggressive strategies used on bermudagrass fairways and approaches in the past few years. The most aggressive strategy – and likely the most effective – is to fraise mow the area. Fraise mowing to a depth of 0.25-0.75 inch is an effective way to significantly reduce grain. Other benefits of fraise mowing include thatch and weed seed reduction. Surprisingly, fraise mowing may not entirely remove all the grain so superintendents are encouraged to continue with varying mowing patterns and frequent brushing and vertical mowing against the grain after the turf recovers from fraise mowing. However, for many courses fraise mowing is simply not an option due to the disruption it causes and the expense of hauling off many yards of material.
A more pragmatic approach is to aggressively scalp bermudagrass fairways. To do this, begin by using vertical mowing equipment and/or a heavy spring-tine harrow rake to stand up the bermudagrass. Work against the grain and make circular passes to aggressively dig into the horizontal stems and stolons. Next, scalp the turf as low as the mowers can be set. The ideal scalping height is between 0.200 and 0.250 inch. The material harvested from this practice will be significant, but not to the extent of fraise mowing.
Healing time will vary, but it typically requires 10-14 days depending on the location and time of year. Avoid the urge to apply a high dose of nitrogen afterward as this will only create more thatch. This practice can be done once or twice during the summer months on bermudagrass fairways and should be included in the agronomic plan every year. Some courses apply sand topdressing to the impacted areas seven to 10 days after the event. However, this is not absolutely necessary.
Fairway grain can be significantly reduced but probably not eliminated with this aggressive scalping process. Surface texture, smoothness and firmness should also improve. Many courses in the West will complete this practice as early as May, but most will wait until July or August when the weather is ideal for recovery on warm-season fairways.
If you've got grain on the brain, try this aggressive scalping practice this summer – even on a small area – and assess the results. Please reach out to your regional USGA agronomist for more information on this strategy.
West Region Agronomists:
Brian Whitlark, regional director, West Region – bwhitlark@usga.org
Ross Niewola, agronomist - rniewola@usga.org