By: Carl Schimenti, Urban Environmental Scientist
Our program has spent quite a bit of time in recent years promoting the practice of rolling. This interest is rooted in research done more than 20 years ago with Bethpage State Park, which found that rolling, in conjunction with other “alternative” practices (at the time) allowed for significant reduction in pesticide use. More research since has continued to support the idea that rolling can provide pest suppression, most notably with dollar spot (1, 2) but also pink snow mold (3, 4).
However, I’m under no illusion that the main topic of conversation around rolling is pest control. It is mainly viewed as a playability practice: more rolling = faster, firmer surfaces for golfers and athletes to play on. But, how much should you roll? If you’re golfers want faster green speeds, how much MORE rolling should you do? If the answer to that question is somewhat knowable, you can start to estimate the added time and resources it will take to achieve that goal.
In 2025, SUNY Delhi student Taylor Brock ran a research study at our Bluegrass Lane Turf Research Center. This was really a mess-around-and-find-out (MAFO) study, investigating the playability effects of rolling, in addition to other aspects such as growth rate, organic matter accumulation, and Poa annua encroachment.
The study was run on both putting green and fairway height creeping bentgrass (A1/A4) on an 18-inch sand-based rootzone. Rolling was applied using a Salsco greens roller. Green speed was measured twice per week, in addition to other variables such as clipping volume, firmness, and visual turf quality. The rolling treatments were:
- No rolling (NR)
- Rolling 3 days per week (3x)
- Rolling 5 days per week (5x)
- Double rolling 5 days per week (10x)
In short: more rolling = more green speed. I had four key takeaways from these data
- The green speed effect from rolling is dynamic through time. Initially, the difference is small, where after two weeks the difference between no roll and 10x treatments was only 12 inches. But over time the effect magnified, ballooning to a 30-inch difference between no roll and 10x by study’s end, and an 18-inch difference between no roll and both the 3/5x treatments.
- While 5x was faster than the 3x treatment, the differences was typically less than 6 inches. This is probably not perceptible by the average golfer (5).
- In general, a rule of thumb number I would conclude from these data is: each additional roll per week will increase green speed by 2.5 inches.
- The 10x treatment did not have any deleterious effects. In fact, abiotic stress tolerance was better in the 10x treatment than the 0x, as evidence from the picture below from July (Figure 1).
Important context here was that this was on a sand-based rootzone in a research setting with no additional traffic. Would a push-up green doing 20,000 rounds a year perform differently? Probably!
Here is where I start to think about practical application. An important concept I have learned from Dan Schied, soon-to-be Emeritus Director of Grounds at Cornell, is wrench time. For any maintenance task there is the time spent doing the actual task (wrench time), e.g. on the roller doing the rolling. Then, there is the other time that elapses while doing things associated with that task that are not the task itself (non-wrench time), such as checking fuel in the roller, loading it on the trailer, driving from green-to-green, waiting for the 6:30am tee-time golfers to play through, etc…
Here is my napkin math on wrench time for rolling (you’ll see where I go with this shortly).
- When you send an employee out to roll greens, I would estimate that 50% of that time is wrench-time. Maybe that’s low, but remember, you have to drive SLOWLY, take the flag out, get the roller loaded 18+ times, among other things.
- Using that 50% wrench time number, let’s say it takes 4 hours to single roll greens. This means 2 hours of rolling, and 2 hours of non-wrench time.
- If I were to double roll, the non-wrench time doesn’t change (2 hrs), but I double the rolling time to 4 hours. Under these estimates, it would take 6 hours.
If I apply this wrench time idea to scenarios of single and double rolling, paired with my rule of thumb estimate from our 2025 data, I can generate the below table that compares time of rolling programs to the estimated green speed effect.
| Table 1. Estimated time to perform rolling program and associated green speed effect | ||||
| Rolling Program | Total effective rolls per week | Time per week (hrs) | Estimated green speed increase (in) | Rolling efficiency (in/hr) |
| 0 rolls | 0 | 0 | – | – |
| 3 single rolls | 3 | 12 | +7.5 | 0.63 |
| 5 single rolls | 5 | 20 | +12.5 | 0.63 |
| 3 double rolls | 6 | 18 | +15 | 0.83 |
| 4 double rolls | 8 | 24 | +20 | 0.83 |
| 5 double rolls | 10 | 30 | +25 | 0.83 |
My wrench time estimate could be incorrect (would be happy to get real data!), but if it’s close, wouldn’t it make sense to roll fewer days per week, but make it a double roll every time? If I can get more green speed for the same amount of time (5 single rolls vs. 3 double rolls), or more green speed for nominally more time (5 single rolls vs. 4 double rolls), isn’t that preferrable?
Perhaps that is a ridiculous recommendation. Rebuttals like “greens might be more inconsistent day-to-day”, or “would double rolling cause more turning injury” are valid concerns. This is the point of MAFO. You should not take these data as definitive, but rather as a piece of a larger body of evidence on rolling. But I can assure you, this rolling recommendation isn’t 10% as crazy as the ones we might begin to make on fairways. For that, you’ll need to wait for part two!