A Closer Look at Our Putting Greens
12 JUN 2020
You have a 10-foot putt for birdie. You are standing behind your ball reading the gentle left to right line you are going to take to make this putt. You take a few practice swings to figure out the speed. You tap your ball on the exact line you drew up with exactly the right weight. The ball should fall in the hole. At RattleSnake we are constantly keeping up with our agronomic practices to ensure your ball rolls smooth and true on every green. We cut our greens at 0.110 of an inch, so you can bet that a single blade of grass out of place will cause imperfections to your ball roll.
There are many factors that affect your ball roll that you probably do not take into account. Things like thatch layer, moisture levels, type of grass, and how the grass is cut will all determine the purity of roll. The least amount of thatch and the drier the soils, the smoother the putt. At RattleSnake we have bentgrass putting greens with the inevitable poa encroachment. As Bill mentioned in last week's article, this time of year the poa is seeding making it less desirable for putting. However, once we get passed the seed head season (about another week or so), poa is actually a very good grass to putt on. Poa tends to get a negative rap in the industry because of its seed head season and its limited root system making it very challenging to manage. But, poa has a bunch-type growth habit that allows the grass to stand straight up and down, this helps us to mow with minimal inconsistencies. Bentgrass, on the other hand, is a lot more reputable. It is easier to manage, but mowing causes the plants to lay down. Because of this, bentgrass has a sideways growth habit with blades of grass growing off each other above ground (called stolons). Once the grass lays down it does not get proper cuts and causes slight bumps or directional imperfections in your line.
This picture was taken on a green at another golf course. This is not at RattleSnake but is an exaggeration of what happens on greens if not attended to. The laydown growth of the Bentgrass is very obvious and mowing continues to just push the grass down rather than getting a good cut. If you were to swipe your hand across the bentgrass to stand it up, the blades would stand close to 5x higher than the poa blades. This is where vertical-mowing comes into place. Vertical mowing breaks the stolons of bent grass, stands the grass up, and pulls up thatch. Once we have opened up into the thatch layer we add a thin layer of top-dressing sand to work in and dilute the thatch. We got our vertical mowing and top-dress in on Sidewinder this week and we are doing the same on Copperhead Monday. Here is a look at our greens after the vertical mowing.
The majority of the grass blades are standing up so when the mower comes around, every blade will be cut at that 0.110 inch. Whenever we get a break in the heat we send our mowers out with brushes ahead of them. The brushes act as a more gentle vertical mow we consider grooming. Funny that poa is under so much scrutiny, yet we are constantly trying to mimic its growth habits on our bentgrass putting greens!
Christine Kumagai, Golf Course Associate Superintendent