The Science of Green Speed (Part 3)

Every golf course green has a speed limit based on various factors. As we have learned in the two previous articles, the “Green Speed” has two MAIN components that encourage and/or limit the speed of greens. In part one, we explained that better mowers and light weight rollers are the key to “Green Speed.” To explain how the PGA Tour play on green with speeds in excess of 11 feet (on the Stimpmeter, see first article) we must ask how many times per day do mowers and rollers get used and at what height.

The newest mowers allow superintendents to mow grass below 3mm in height, which will produce faster green speeds. Your average golf course will cut the greens every morning before play at 3.5mm height and will be rolled two to five times a week right after mowing. For a PGA tournament the mower will be sent out every morning and every evening to cut the greens and in some cases the greens can be cut twice in the morning before play and twice in the evening after play. Added to mowing, PGA Tournaments often have the greens rolled in the morning before play and in the evening after play.

  # Cuts/Week #Rolls/Week
PGA Golf Course 14-28 7-14
Average Golf Course 6-10 2-5

Making a standard assumption that it requires 4 hours to cut 18 greens and 4 hours to roll 18 greens, your average golf course can only afford to cut and roll once per day versus a PGA golf course. A PGA tournament uses an incredible amount of staff and volunteer hours mowing and rolling greens. If there was a desire to consistently maintain greens at the level of a PGA tournament, maintenance requirements would dramatically increase. Because of the significant use of rollers and mowers for a PGA tournament, there is an incredible amount of maintenance work that occurs before and after the tournament.

This brings us to part two of “The Science of Green Speed”. To say that a golf course superintendent walks on a razor's edge when maintaining putting greens for a PGA golf tournament is an understatement. Every small reduction in height of cut (0.025”) on putting greens reduces the photosynthetic potential of the putting green by 50%, and over time the plant will die back and thin out. Although lightweight rollers smooth putting greens, rolling more than seven times per week has shown to cause the plant to die back and thin out. Researchers from Michigan State has indicated there is a small level of return to rolling; too much of a good thing will cause putting greens to die back, thin out and be more susceptible to disease, like fungi.

If each golf course set a SPEED LIMIT, this in turn sets how many times and at what height, the greens can be cut, as well as how often can they be rolled during the week. This also sets how much maintenance must be done to ensure the health of the putting greens. There is direct association of increased cutting and rolling to the increased stress of a putting green. The stress on the plant can be solved by good SOIL PHYSICS, good SOIL BIOLOGY, increased CULTIVATION, increased IRRIGATION and of course FERTILIZATION. Unfortunately all of these parts of the EQUATION (read Part 2) increase the cost of maintaining putting greens. However, without increasing the maintenance levels and simply cutting lower and more often, and rolling more to gain green speed, there will be a breaking point to the putting green. Thus, set your SPEED LIMIT, because as we all know excessive speed actually kills putting greens.