Nap
Nap refers to the direction of grass growth on the green, which can accelerate, slow down or pull the putted ball sideways.
The nap forms because blades of grass do not stand upright but lie in a preferred direction, usually towards the sun or the water. If you putt with the direction of growth, the ball runs faster and breaks less. If you putt against it, the grass slows the ball and the putt gets slower. Across the direction, the ball can additionally be deflected. On native grasses in Germany the nap is usually weak. On bermudagrass courses in warm regions, by contrast, it is a factor to be taken seriously when Reading the Green.
You can recognise the nap from the appearance of the green. If the surface looks shiny and bright from your viewing angle, the blades lie away from you and you are putting with the nap. If it looks dull and dark, the blades face you and you are putting against it. An example: on a holiday course your ball sits five metres from the flag and the green looks dark. You give the putt noticeably more speed than usual and allow generously for the Break, because the grass holds the ball back as well. After a hole or two you will have developed a feel for the effect.
A common misconception is confusing it with the break caused by the slope. Nap and gradient are two different influences that can add up or cancel each other out. On most German greens the slope clearly dominates; the nap only plays a noticeable role with certain grasses and seasons. Anyone who obsesses over every barely visible direction of the grass at home complicates their putting for no gain. When travelling to southern golf regions, that attention pays off immediately.
FAQ
How do I recognise the direction of grass growth on the green?
Look at the green from behind your ball: if it looks shiny and bright, the blades lie away from you and you are putting with the nap. If it looks dull and dark, the blades face you and you are putting against it. After a hole or two you will have a feel for how strong the effect is on that course.
Do I need to worry about the nap on German courses?
Usually not to the extent you might think. On native grasses the slope clearly dominates the break, and the nap only plays a noticeable role with certain grass species and seasons. Anyone who analyses every barely visible direction of the grass at home complicates reading the green without any real gain.
How do I putt correctly against the direction of growth?
Give the putt noticeably more speed than usual, because the grass slows the ball. Also allow more generously for the break, because the slower ball has more time to drift. On holiday courses with a strong nap, it pays to treat the first holes deliberately as an adjustment period before you sweat the important putts.