What affects the grain of a green?
Putts down grain (in the same direction the grass is growing) go faster than putts into the grain (in the opposite direction from the grass growth). The grain of a course, of course, has an effect on where you have to aim a putt.
The grain of the green can be affected by the position of the sun in the sky. Blades of grass will reach towards the sun as it moves across the sky, so the grain might vary slightly throughout the day.
Looking at the cup shows you which way the grass is growing. Especially in the afternoon, you may see a ragged half and a smooth, or sharp, half on the lip of the cup — that shows the direction in which the grass is growing. The ragged look is caused by the grass’s tendency to grow and fray. If you can’t tell either way, go to the fringe (the edge of the green). The grass on the fringe is longer, so you can usually see the direction of the grain right away.
Also keep an eye out for nearby water sources like ponds or creeks; the grain will usually run towards water.
What affects the break of a green?
Many different features can determine the break, features such as water and mountains, the grain of the grass, and most importantly, how hard you hit the ball.
Most golf courses trim their greens from a different direction every day to keep the grain even. If the golf course cuts their grass in one direction every day it will start to grow in a distinct pattern, leaning to the side and pulling golf balls in that direction.
First, find the natural slope of the terrain:
If there are mountains nearby, finding the natural slope is easy. The slope on every green is going to be “from” the mountain. Unless, of course, an architect thought it would be a good idea to bank some holes toward the mountain.
If the course is relatively flat, go find the pro or course superintendent, and ask about the area’s lowest point. Once you find out where that point is, take advantage of gravity.
After you know the lowest point, look at each green in detail. If you’re on an older course, the greens probably slope from back to front because of drainage. Greens nowadays have more humps and undulations than ever and are surrounded by more bunkers. And the sand tells a tale: Most courses are designed so that water runs past a bunker and not into it. Take that insight into account when you line up a putt.
Tip number 1: Analyze the grain
Walk in a circle around the green until the grass behind your ball appears to be slightly lighter; you are now looking in the direction of the grain. When the grass looks darker you’re looking against the grain.
Putting with the grain means your ball will roll 25-30% faster. Putting against the grain will move your ball slower.
Tip number 2: Get a new perspective
Never hit the ball before you view your put from the other side of the hole.
The ball moves so fast when you first hit it that the grain doesn’t have a chance to ‘grab’ it and pull it off course. The last 2/3 of your putt closest to the hole is what you really need to pay attention to.
By viewing your putt from the other side of the hole you’ll get a clearer idea of what those last few feet of the green look like.
Tip number 3: Trust yourself
Take a quick look around, use your best judgement, and let your subconscious and muscle memory guide your swing. Trust that you will see all that needs to be seen. Have confidence in your decision by the time you hit the golf ball.
Don’t spend too much time over-analyzing your putting line or you’ll start to see things that don’t exist.