Green Speeds and the Stimpmeter Explained
The “stimp” or “stimp rating” of a putting green is a numerical value that represents how fast the golf ball rolls on the putting surface. Golfers call this rating the green speed.
Greenspeed is best measured with a Stimpmeter which should be part of the equipment of every greenkeeper. Most courses will use a stimpmeter regularly so that greenspeeds can be accurately monitored.
A reading of below six would indicate very slow greens; eight to 10 would be quite fast while 10 to 12 would be tournament speed. Augusta greens would normally run at 12 on a flat surface but could be as quick as 20 to 30 down one of those notorious slopes.
At Augusta, the greens are normally amazingly fast at 6.00 feet per second. The distance a golf ball rolls on a pulling green is determined by the force imparted and the friction generated between ball and surface. Therefore, to speed up greens, the coefficient of friction must be reduced.
So, how do we do this? Firstly, the type of grass is important. Fescue is a fine grass with a strong leaf, but fescue greens will never be as fast as greens of Bentgrass, which has a softer leaf. Despite all the criticism about it, Poa Annua (meadowgrass) is also quite capable of producing an extremely fast surface, as we saw in the 1994 US Open at Oakmont.
Height of cut is an obvious factor if speed is to be increased, but low heights of cut will not automatically lead to fast greens. There are other factors involved.
A height of cut of 5mm, or three sixteenths of an inch, is fairly common for growing conditions but to produce extreme pace, a height of 3mm would probably be required.
When the USGA introduced the Stimpmeter in 1978, it had just completed a year-long test of 581 courses. It found the average green speed to be about 6.5. Less than 2% of the 2,116 measurements recorded were higher than 9.