What's the deal with grain?

[natureboy]

So at the event at Kapalua, announcers pointed out what they called an effect of grain on a putt by Ryan Moore (gif below) where the trajectory of a left-to-right putt seems to change in a slight double-break.

Objections were raised that studies of grain effects indicated they were minimal...up to 2 inches on a 20' putt. Not sure if that was for mostly level or appreciable slope. This jibes with what I recall about grain from one of the original empirical looks at grain in Vector Putting (since superseded / updated by AimPoint)...that it was relatively a small contribution vs. slope.

From what I've come across, the least 'grainy' grass is supposed to be Poa Annua as it has the most vertical 'growth habit', while creeping bentgrass has more tendency to develop grain, and Bermuda even more (greens at Kapalua).

The intuitive assumption might be that amount of deflection is spread out evenly along the whole length of the putt (like slope is - ball is always falling) so grain-induced deflection is like .008" per foot of putt length. I'm not convinced that's how it would work as it seems likely that grass grain (if present) would have more effect on a slower moving ball (end portion of longer putts or most of a short putt that is only intended to go a bit past the hole). So shorter putts might experience a greater percentage of deflection (but still under 2").

Most of the information says that grass grain tends to follow the slope (downhill) if it's present. So grain and slope would typically be aligned the same. On that basis it's implied that in the GIF above there was most likely a slope change that is reflected in the color change of the grass. The more closely mown the grass, the less the grain tends to be in play because the stems are cropped nearer the ground.

But here's a video where grain has developed independent of slope sun or maintenance practices due to some particular quirks of the site, green location, or the plants. Grain changes 180 degrees where there is no appreciable change in slope.

Based on the video above it seems possible that the color change apparent on the green in the Kapalua GIF isn't a change is slope, but only a 'random' variation in the grain as in the video above. In that case it seems like the 'jog left' the putt seems to take might be a case of the 'rising fastball' effect where the anticipation of the curve on the early phase of the putt as the ball is falling with gravity on a 'fast' portion of grain continues to fall, but does so more slowly on a 'slow' portion of grain (opposite the slope / falling ball) and tracks into the hole on a less curved than expected line for the average 'grain with the slope' green speed?

So what's your experience? Do you find that grain primarily follows slope so that you can use visual 'grain' cues to help find slope inflections? And do you find patches of grain on some courses / holes that does not follow the downhill slope? If so, how frequently, and do you notice any common patterns or is it more random? If you notice grain effects, what type of grass is it usually? Do you find short putts have an equal amount of break as longer putts or do you find the effect of grain proportional to the length of the putt? Do you notice differing effects from grain if the average stimp is high or low?

Here's some general info on grain and green agronomy (who knew there was a global turf network):

 

Edited January 9, 2017 by natureboy

[Club Rat]

On our bent grass greens, the grain typically affects Speed. Down hill with the grain are lighting quick, against the grain is typically slower.
The grass color is noticeably different, some areas almost appear having a Metallic appearance when looking down grain.
Looking at the line from the opposite direction, the appearance is difficult to see.

[paininthenuts]

It's all about playing to conditions. We were never meant to putt on carpets !!

[saevel25]

1 hour ago, natureboy said:

So what's your experience? Do you find that grain primarily follows slope so that you can use visual 'grain' cues to help find slope inflections? And do you find patches of grain on some courses / holes that does not follow the downhill slope? If so, how frequently, and do you notice any common patterns or is it more random? If you notice grain effects, what type of grass is it usually? Do you find short putts have an equal amount of break as longer putts or do you find the effect of grain proportional to the length of the putt? Do you notice differing effects from grain if the average stimp is high or low?

 

In the midwest there is little to no grain on the greens. I've played in Florida and the grain pretty much follows the slope of the green. 

For me, I think of grain more in terms of influencing speed. Putts with the grain are faster, and will break more. 

[Patch]

I think like most plants, grass will follow (point) to the sun.

A green's undualations has more effect than grain probably has, especially the the slower the ball rolls.  

As for the grain itself, I don't worry about it that much when putting, as  I tend to roll my putts pretty fast. 

I do think from past expirience, that grain becomes more prevalent, the longer the grass has been allowed to grow from it's last mowing. However, since most courses have a consistent maintenance schedule for their greens, what ever effects grain might have on a ball is minimal. 

This is my story and I am sticking to it. 

[iacas]

16 minutes ago, Patch said:

I think like most plants, grass will follow (point) to the sun.

It doesn't. To maximize sun exposure the blades of grass would actually want to be perpendicular to the sun, not pointing at it exposing the "end" to the sun.

---

• Grain primarily follows the slope of the green.
• You can find examples of the opposite, but they're very rare.
• Bent grass greens have very little grain.
• The 2" over 20' was the maximum variance possible, and that was before an adjustment for speed.
• Grain primarily affects speed. If a green stimps at 10, into the grain may be as low as 9 and down-grain may be as fast as 11. See bullet point number one.
• Golfers probably shouldn't worry about grain much at all, except possibly to consider the item just above.

That's about it. There's no big mystery to grain.

[natureboy]

4 hours ago, iacas said:

Grain primarily affects speed.

I was familiar with that, and I figured that's likely the primary way that grain would make its small influence on putt direction. I understand it's not a primary element of concern vs. slope (except maybe to help ID slope inflection areas). But I'm still curious about unusual cases.

What about the hypothetical of a putt sent toward the hole where there is a section of grain in the first half (or so) of the putt that roughly follows the direction of slope such that the putt is falling ~ with the grain. Now partway through the putt, the ball crosses to a section of 'grain' that is 180 degrees opposite to the first section such that the putt is now falling ~ into the grain. Roughly per the representation below:

What's a reasonable expectation of the maximum effect on the ball and the shape of the putt trajectory?

[bkuehn1952]

There are so many other ways I lose strokes over the course of the round, misjudging grain on a 20+ foot putt is unlikely to create a lot of pain for me compared to other issues.  Years ago I played reasonably frequently in FL.  I spent too much mental energy on "the grain."  Eventually I decided to not get so wrapped up in "the grain" and just played for quicker downhill putts, slower uphill and slightly greater breaks when going across a slope.  Here in MI, I pretty much ignore "the grain" since from my uneducated perspective, "the grain" on our northern greens has an extremely subtle effect.

As to the putt in Hawaii, rather than grain, it could just be a "bump" or unevenness next to the hole, perhaps caused when they set the hole/liner.  However, it is too simple an explanation for TV so they probably wanted to jazz it up by talking about grain.

[Club Rat]

9 minutes ago, natureboy said:

What's a reasonable expectation of the maximum effect on the ball

I had a good discussion with our GK a few beers back and he indicated GS is basically "friction"

Grass types, sand, moisture are what influence friction as a ball rolls across a surface.

We did not discuss "grain" to any extent, mainly because of maintenance of the greens eliminates any grain effect. It's controlled.

So, a reasonable expectation your considering would only be in certain areas on the greens.

Consider putting through a small area of the green with casual water or dew.

Areas with Grain would be a similar effect on the upslope of grain.

People who play Bermuda greens on a regular basis most likely become accustom to reading grain on them.

When I golf on Bermuda, I'll look at the cup to see the grass growing over the edge.

If I see it growing over the edge on my line on a downhill putt, I'll be ginger with it, let it rollout into the hole.

On uphill putt's in the opposite direction, a ball will circle the rim easier and lip out sometimes.

 

Oh, really good videos, thanks for posting.

[Golfingdad]

6 hours ago, iacas said:

Grain primarily affects speed. If a green stimps at 10, into the grain may be 9 and down-grain may be 11.

Golfers probably shouldn't worry about grain much at all, except possibly to consider the item just above.

That's the answer right there.  Playing grainy greens?  Hit your uphill putts with more weight and your downhill putts with less.  The end.

[sjduffers]

I beg to differ somewhat: I regularly play a course on the Big Island of Hawaii that has kikuyu grass on both the fairways and the greens, basically everywhere.  This is somewhat rare: kikuyu is usually used only on the fairways and rough, with something like a strain of bermuda for the greens. Besides interesting/positive agronomic properties, that kind of grass is very strong and grabs your club in the rough and even in the fairway if you don't use the bounce around the greens. Beware!

On the greens, it is like velcro when against the grain and pretty smooth when going with the grain: the difference in speed is huge going with vs against the grain, much more so than 9 vs 11 on the stump: more like 6-7 vs 10!  As for the amount of grain, it's enough to move a ball over 6 inches in the last 2-3 feet of a putt as the ball dies. Yes, clear across the hole! And you wouldn't believe how hard you have to strike a putt going uphill into the grain, against the wind. 

The grain general direction is towards the sunset, which is also the general slope of the surrounding terrain, but it does not quite follow each and every little slope or contour of the green. It can visibly be checked at the cup as the side towards the grain is very frayed, much more so than with bermuda grass.

The first time I played there, I couldn't believe it, but grain is definitely a big factor on this course, nearly as much as slope (not to mention the wind, which can easily gust to 30mph+). Of course, in many areas of this course, it's downhill with the grain and uphill against, but that is far from being the overwhelming rule. In particular, there is an elevated green sloped back to front (back much higher to help hold shots) but the grain is going front to back and despite the significant rise from front to back, it is extremely easy to land a ball at the front of the green and see it roll all the way through, off the back, even with a PW-8i, thanks to the grain!

Edited January 9, 2017 by sjduffers

[Golfingdad]

1 hour ago, sjduffers said:

On the greens, it is like velcro when against the grain and pretty smooth when going with the grain: the difference in speed is huge going with vs against the grain, much more so than 9 vs 11 on the stump: more like 6-7 vs 10!

Yeah, I was fortunate enough to play Kapalua this summer and the difference seemed bigger there as well.  His point, of course, wasn't that it would always be 2 point difference or anything, just that that is really the only place you'll see it pop up.

1 hour ago, sjduffers said:

The first time I played there, I couldn't believe it, but grain is definitely a big factor on this course, nearly as much as slope (not to mention the wind, which can easily gust to 30mph+). Of course, in many areas of this course, it's downhill with the grain and uphill against, but that is far from being the overwhelming rule. In particular, there is an elevated green sloped back to front (back much higher to help hold shots) but the grain is going front to back and despite the significant rise from front to back, it is extremely easy to land a ball at the front of the green and see it roll all the way through, off the back, even with a PW-8i, thanks to the grain!

I love the Big Island! :)  Mind if I ask, though, what makes you think that the green slopes from back to front if the ball rolls through the green on approach shots?  I've played a lot of holes where I think I can tell which way the green slopes, but after I play it, I realize I was wrong.

[sjduffers]

44 minutes ago, Golfingdad said:

Mind if I ask, though, what makes you think that the green slopes from back to front if the ball rolls through the green on approach shots?  I've played a lot of holes where I think I can tell which way the green slopes, but after I play it, I realize I was wrong.

I understand the visual illusion type of green, where due to the general layout, you're going down a big hill/mountain and the green is still going downhill and your eyes are totally deceived going back the other way, where it feels like downhill but is actually uphill, just less uphill than the fairway and the mountain behind look like.

This hole is the opposite: from the back, it looks uphill because the general layout is uphill, (if you ignore the big swell in front of the green that makes the green elevated). However, the green is built to allow approaches to hold better and is thus sloping back to front, and if you putt from the back towards the front, there is definitely a downhill slope to the putt, but the grain is going the other way (towards the sunset and/or the general lower slope of the whole hill, which in this case is Mauna Kea, a big 14,000ft hill! The approach shots roll out a lot because the green is elevated (pretty steeply too) and the ball rolls down grain (even though it may be uphill) and usually, with the trade winds, downwind too. 

As I said, rather the usual slope or sometimes slope + wind, at that course (Waikoloa Village, if you must know) you have to contend with slope + wind + grain.

45 minutes ago, Golfingdad said:

Yeah, I was fortunate enough to play Kapalua this summer and the difference seemed bigger there as well.

That could be more due to the huge changes in elevation, even on the (large) greens, than to the type of grass and grain. It's bermuda there, isn't it?

Edited January 10, 2017 by sjduffers

[iacas]

4 hours ago, natureboy said:

What's a reasonable expectation of the maximum effect on the ball and the shape of the putt trajectory?

It would be almost the same as if there was no grain, because the grain affects the putt and lets it break a little more in the first part, and then helps "hold it up" a little tiny bit during the latter half.

So the read would be almost exactly the same as on a green with no grain at all.

Note of course it's highly unlikely that you'll find a green with grain growing like that with an inflection point and yet constant slope.

I don't think you understood what I meant when I shared the Mark Sweeney stuff from above.

3 hours ago, Golfingdad said:

That's the answer right there.  Playing grainy greens?  Hit your uphill putts with more weight and your downhill putts with less.  The end.

You can adjust your reads, too. But the read is accurate for the effective stimp of the green.

And that's only for uphill/downhill putts. Most of the time you hear announcers talking about grain it's on a cross-grain putt.

2 hours ago, sjduffers said:

On the greens, it is like velcro when against the grain and pretty smooth when going with the grain: the difference in speed is huge going with vs against the grain, much more so than 9 vs 11 on the stump: more like 6-7 vs 10!

The faster greens are the more the differences in feel will be different. If you play on Oakmont or Augusta National, you feel like you have to HAMMER the uphill putts, in part because the downhill putts are so slippery.

Let's say 20' level requires a stroke with 10 units of force at Augusta National. A downhill putt might of 20' might require 2 units and an uphill 20' putt might require 17.

Yet at your local muni, a putt with 10 units of force might only go 12.5 feet. A downhill 12.5 footer might require a force of 7 units, and an uphill 12.5' putt might require 12. They're closer to each other, because the friction of the grass itself is playing a greater role.

There's a greater disparity on the faster greens because gravity takes on a larger percentage of the relevant forces acting upon the ball (because the relative weight of friction decreases). This creates a larger "gap" between uphill and downhill putts on faster greens.

The grain on a stimp 8 green is often WORSE than the grain on a stimp 13 green. After all, the grass is longer. Yet it FEELS like the stimp 13 green has a greater disparity into the grain versus down grain… because even without grain, it has a greater disparity.

We can't easily separate out what the grain is contributing versus what the slope and stimp are contributing towards our feels.

The most we advised our players to adjust their AimPoint reads back in the days of using the charts with different stimps was two: if the stimp was 10, and you were playing the grainiest greens in the world, you could go to 8 for a putt within 30° uphill, 9 for putts from 30-60°, and vice versa for the downhill putts.

Most of the time we told people not to worry about it, or if they were playing noticeably grainy greens, to adjust by 1 on the putts that were within about 30° of straight uphill or downhill… which didn't change their reads much because the putts close to straight don't break much as it is, so many would just stay on their "9" chart all day and adjust by an inch or two or three when they had an uphill or downhill putt, depending on the length.

2 hours ago, sjduffers said:

As for the amount of grain, it's enough to move a ball over 6 inches in the last 2-3 feet of a putt as the ball dies.

You won't like to hear it, but I really doubt that's accurate. Mark Sweeney would disagree with you, as would I. On a stimp 10 green, even a 3% slope will cause a 3' putt to break only 5 inches.

2 hours ago, sjduffers said:

The grain general direction is towards the sunset, which is also the general slope of the surrounding terrain

All the greens slope to the west? That doesn't make sense to me.

2 hours ago, sjduffers said:

The first time I played there, I couldn't believe it, but grain is definitely a big factor on this course, nearly as much as slope (not to mention the wind, which can easily gust to 30mph+).

Nothing I've ever read or seen by people with good science leads me to believe that's even remotely true.

Again, on the grainiest greens, Mark Sweeney found that a 20' putt was affected by about 2 inches. That means that a putt that he'd predict to break 27" would break 29". If he could magically flip the grain to be 180° (up the slope), it would break about 25".

I think it's easy to talk yourself into these kinds of things, particularly if you don't appreciate how much more fast putts break (or putts from 60° downhill, 30° above perpendicular to the slope - which at higher green speeds break MORE than putts straight across the slope).

I don't think we'll get anywhere with this conversation, either. I just have my science and some experience on greens with grain (I spent a good amount of time with a relatively grainy green in FL a few years ago, and one on Kiawah Island too during an AimPoint yearly workshop)

7 minutes ago, sjduffers said:

I understand the visual illusion type of green, where due to the general layout, you're going down a big hill/mountain and the green is still going downhill and your eyes are totally deceived going back the other way, where it feels like downhill but is actually uphill, just less uphill than the fairway and the mountain behind look like.

I'm not really interested in visual illusions. The green slopes the way it slopes; I don't care if it appears to slope differently. Grass doesn't have eyes and isn't fooled by visual illusions.

Grain, when present, almost always grows downhill.

[Golfingdad]

1 hour ago, sjduffers said:

(Waikoloa Village, if you must know)

Haha, cool!  I've stayed and played at the Waikoloa resort courses but only driven by the Village course.  Love that area.

1 hour ago, sjduffers said:

That could be more due to the huge changes in elevation, even on the (large) greens, than to the type of grass and grain. It's bermuda there, isn't it?

Yes, it's all bermuda, and yes, it could more be more due to the slopes.  That's why I said "seemed," because my perception during/after one loop around the course was that the difference between downhill/downgrain putts and uphill/upgrain putts was enormous.  But the amount of that difference that was due to the slopes versus the grain I could not quantify.  Other than just to recognize that they were really grainy.

[sjduffers]

46 minutes ago, iacas said:

The faster greens are the more the differences in feel will be different. If you play on Oakmont or Augusta National, you feel like you have to HAMMER the uphill putts, in part because the downhill putts are so slippery.

I am well aware of this.

46 minutes ago, iacas said:

3 hours ago, sjduffers said:

The grain general direction is towards the sunset, which is also the general slope of the surrounding terrain

All the greens slope to the west? That doesn't make sense to me.

That's not what I said. At that course, the general landscape goes towards the place where the sun sets, ie. West, much like at Kapalua, the general landscape slopes towards that bay, i.e. more or less North.  After all, the course I am talking about is at about 1000ft elevation on the side of a big ass mountain, the extinct volcano Mauna Kea, peeking at nearly 14,000ft.

Yet, greens can be contoured to slope one way or the other, by moving terrain, adding soil, etc... (on the Big Island, there isn't much native soil anyway, it's a thin layer on top of lava rock, so some big efforts had to be made to lay out a course there, in the early 70s). So, some, many in fact, greens generally slope towards the West at that course, but not all, including the one I was describing to @Golfingdad.

46 minutes ago, iacas said:

I'm not really interested in visual illusions. The green slopes the way it slopes; I don't care if it appears to slope differently. Grass doesn't have eyes and isn't fooled by visual illusions.

Admittedly, this was slightly OT, but was in response to the question asked by @Golfingdad on how I knew that the putt I was describing was indeed downhill, and not uphill. Please re-read the following paragraph for something more on topic.

Look, I am a decent putter at 30.5 putts per round average. I have seen many different green complexes, at different speeds (not Augusta speed though, I admit ), some with grain and some without, and generally I agree, again, you are right.

But this place is something else: I have seen several putts, from others and from me, completely crossing the hole on a slight slope (e.g. 1% or maybe a bit more, but not close to 3%) as the putt was dying while they were "in the jaw" just a couple of feet prior, a move of 6 inches in 2-3 feet.  You may have never seen this situation as kikuyu grass is not common at all on greens: it's the only course where I have seen it: I have seen plenty of kikuyu on fairways and rough though and as you know, that stuff is real strong (much stronger than bermuda). The short grass on the green is similarly strong...

[iacas]

14 minutes ago, sjduffers said:

That's not what I said.

Okay. I get what you're saying about that now.

14 minutes ago, sjduffers said:

But this place is something else: I have seen several putts, from others and from me, completely crossing the hole on a slight slope (e.g. 1% or maybe a bit more, but not close to 3%) as the putt was dying while they were "in the jaw" just a couple of feet prior, a move of 6 inches in 2-3 feet.  You may have never seen this situation as kikuyu grass is not common at all on greens: it's the only course where I have seen it: I have seen plenty of kikuyu on fairways and rough though and as you know, that stuff is real strong (much stronger than bermuda). The short grass on the green is similarly strong...

Would you settle for me saying "Maybe, because nothing like this is impossible"?

I'd love to get there to film it sometime… even if it's just ultimately a curiosity or an exception.

[sjduffers]

58 minutes ago, iacas said:

Would you settle for me saying "Maybe, because nothing like this is impossible"?

I'd love to get there to film it sometime… even if it's just ultimately a curiosity or an exception.

Absolutely! You would find it "interesting" I am sure, especially on one of those days when the trade winds blow to 25+mph, gusting to 30-35mph. Then you would believe the 3 variables: slope, wind and grain.

If you ever make your way there, let me know as I might be there too and would love to see your reaction and then get you a cold beer!