Every morning, my team checks the speed of the practice green to be sure we are staying in the range we feel keeps the putting surfaces challenging for the better players and fair for the higher handicappers. This is a delicate balance and very subjective to golfers. There has never been a Golf Course Superintendent, who didn’t hear the complaint: “The greens are too slow, or the greens are too fast.” Green speed is often determined by a few things, the key being the slope of the greens. Golf courses with flat greens can get away with faster green speeds compared to that of a Club with undulating greens. Using the example of a car, you can drive 100 mph on a highway that is wide and flat, but would you take that same speed on our mountain roads? Probably not. So, to start off, we’ve found that 11-12 feet is the stimpmeter reading that seems to fit our membership well for everyday play. There is nothing that piques the interest of golfers on the practice green that see us, stimpmeter in hand, rolling golf balls back and forth. It always generates fun conversation.
In the 1930s, Edward S. Stimpson, the 1935 Massachusetts Amateur champion, addressed this problem: how to achieve accurate, objective, statistically valid measurements of the speed of a putting green. Known as the father of the Stimpmeter, Edward S. Stimpson was an accomplished golfer. The result of his efforts was the Stimpmeter. What began as a wooden, homemade instrument, Mr. Stimpson's device was later modified by the USGA's technical department in the mid-1970s and made available to golf course superintendents and course officials in 1978. As green speeds have steadily increased since its release in 1978, the Stimpmeter was further modified in 2012.
The Stimpmeter is a simple, accurate device manufactured by the USGA that allows us to make a standard measurement of, and place a numerical figure on, the speed of a putting green. It does so by measuring ball roll distance. The Stimpmeter is an extruded aluminum bar, 36 inches long, with a V-shaped groove on each side that extends along its entire length. It has a precisely milled ball-release notch, positioned approximately 30 inches from the tapered end that rests on the ground. The ball-release notch is designed so that a ball will always be released and begin rolling when the Stimpmeter is raised to an angle of approximately 20 degrees with the putting surface.
As stated, green speed is not at all a speed, usually measured as distance over a period of time. For example, miles per hour or feet per second. Rather, green speed is simply the distance a golf ball rolls off the end of the stimpmeter. Without getting too deep in the details, an accurate measurement is gained by rolling three golf balls one direction, then turning around and rolling three golf balls the other direction. This prevents a course official from rolling a ball down a hill and getting an inflated reading. Essentially, provided the golf balls stopped within 6” of each other, the numbers are averaged together to give the official reading. For example, if I roll 3 golf balls one direction and get 11’, and then do the same the other direction and get 11’ 6”, I simply add the two numbers together and divide by two; the green is rolling 11’ 3”.
The stimpmeter was a tool developed to help superintendents keep consistency across the golf course. The goal was to quantify the consistency of the 11th green compared to the 18th green, and so on. Of course, over time it fell into the wrong hands and somehow turned into a device that some unfairly judge their Superintendent with. It has often got many good superintendents in trouble, trying to obtain a specific desired speed at a time of year when it wasn’t practical. In order to speed up a putting green, often requires agronomic practices that may not be in the best interest of plant health. For example, anything that reduces friction, will increase “green speed.” This may mean mowing at an extremely low height of cut or more frequent mowing. Excessive rolling and thinning the turf with groomers also increases speed. Doing these practices at the wrong time of year could be, and has been, disastrous for some superintendents. That’s why as a Superintendent, I consider it part of my job to educate those who influence golf course standards.
One aspect that has a tremendous amount of influence on green speed, is humidity. Humid conditions not only work against the golf ball itself, after you strike it with your putter, but high humidity can cause grass blades to swell, leading to more friction working on the golf ball. This is typically why greens are faster in spring and fall (lower humidity), compared to summer. Further more, cooler temperatures cause the turf to tighten up, as opposed to swelling, and the reason for those super fast greens during the autumn season.
Next question: Are greens faster in the morning or the afternoon? This is another great debate and I think there are is another factor determining the answer to this question The main factor is how much fertilizer the greens have access to. A green growing under a high nitrogen content, would be slower in the afternoon because the turf grows a 1/16" or more, increasing friction on the golf ball. But turf growing under low amounts of Nitrogen fertilizer (the way I prefer) are faster in the afternoon because the growth in minimal and moisture isn't present during the afternoon hours. Moisture on the leaf blade will always slow a golf ball as it rolls across the putting green.
How about turf variety or species? First, Poa annua greens are usually faster in the summer because Poa annua can tolerate lower mowing heights compared to bentgrass. Furthermore, it is far denser than any other species of turf, leading to smoother ball roll. But, new varieties of Bentgrass aren't too far behind. Our 12th and 14th greens were sodded with 'Pure Distinction,' a creeping bentgrass variety that rivals Poa annua in terms of density. The downside of Poa annua is the seed head it produces in April and May and the varying growth rates of the species at that time of year. These factors influence ball roll in terms of speed and smoothness.
I hope this gave you a little more insight into a topic that everyone has likely heard about, at your Club or through commentators of televised golf events.
