Editing Golf course (section)

===Greens<span class="anchor" id="Putting green"></span>===
{{see also|Greenskeeper}}
[[File:OldHeadGolfLinks18thHole.jpg|thumb|The 18th hole at the Old Head Golf Links on the [[Old Head of Kinsale]]]]
The ''putting green'', or simply the ''green'', is an area of very closely trimmed grass on relatively even, smooth ground surrounding the hole, allowing players to make precision strokes on it. To "putt" is to play a stroke on this surface, usually with the eponymous "[[putter]]" club, which has very low loft so that the ball rolls smoothly along the ground, and hopefully into the cup. The shape and topology of the green can vary almost without limit, but for practical purposes the green is usually flatter than other areas of the course, though gentle slopes and undulations can add extra challenge to players who must account for these variations in their putting line. The green typically does not include any fully enclosed hazards such as sand or water; however, these hazards can {{nowrap|be{{tsp}}{{mdash}}{{tsp}}and}} often {{nowrap|are{{tsp}}{{mdash}}{{tsp}}placed}} adjacent to the green, and depending on the shape of the green and surrounding hazards, and the location of the hole (which often changes from day to day to promote even wear of the turf of the green), there may not be a direct putting line from a point on the green to the cup.

Golfers use a method known as "reading" the green to enhance their chances of making a putt. Reading a green involves determining the speed, grain, incline, decline and tilt of the green on the line of the putt. Most putts are not struck directly at the hole, instead they must be struck to take into account the characteristics of the green to arrive at the hole at the proper angle and speed. The best players will read the green by walking around the green and studying the characteristics of the green before addressing the ball. Many golfers consider reading the green and putting to be the most difficult part of the game.

The green is typically surrounded by slightly higher grass, cut at a height between that of the green and fairway, and then by the fairway and/or rough. This longer grass surrounding the green is known as the ''fringe'' and is designed to slow and stop balls rolling along the green from an approach shot or errant putt, preventing them from exiting the green. Though putting strokes can be made on it, the higher grass can interfere with the path of the ball, so players often choose to use a lofted club such as an [[iron (golf)|iron]] to make a "[[chip (golf)|chip shot]]" or a "bump and run", where the ball carries in the air for a few yards and then rolls along the green like a normal putt.

The grass of the putting green (more commonly just "green") is cut very short so that a ball can roll for a long distance. The most common types of greens are for cold winter, but warmer summer regions (i.e., not extremely warm, as in the Southern and Southwestern United States) are bent grass greens. A green may consist of a thin carpet so that bad weather is not allowed to become a serious factor in maintaining the course. These are considered the best greens because they may be cut to an extremely low height, and because they may be grown from seed. Bent grass does not have grain, which makes it superior as a putting surface. However, bent grass may become infested with ''[[Poa annua]]'', a costly and time-consuming weed. Augusta National is one of many golf courses to use this type of green. The original design of Augusta National did not include bent grass greens, but in the early 1980s the greens were converted from Bermuda to bent grass. This affected the speed of the greens, making them too quick, and several areas were subsequently remodelled to reduce the slopes and make them more playable.<ref>{{cite news |last1=Madden |first1=Michael |title=Master builders change course |url=https://www.newspapers.com/image/437619497/ |access-date=11 August 2023 |work=The Boston Globe |date=10 April 1986 |page=56 |via=Newspapers.com |url-access=subscription}}</ref> Many other golf courses subsequently made the decision to change from Bermuda to bent grass when they observed increased business at courses that had already changed over.<ref>{{cite web|url=http://usatoday30.usatoday.com/sports/golf/masters02/2002-04-11-grass.htm|title=Bermuda, bent, rye: Grass types make big difference|work=USA Today|access-date=12 November 2016}}</ref>

Another type of grass common for greens is TifDwarf Hybrid Bermuda (other variants exist, but TifDwarf is one of the most common), or simply Bermuda grass. Bermuda is more common in regions that have very warm summers and mild winters, such as the Southern and Southwestern United States. Red Bridge Golf Course was the first course in North Carolina to utilize a special Bermuda called Mini Verde. A green is generally established from sod which has had the soil washed off of it (to avoid soil compatibility problems) and which is then laid tightly over the green, then rolled and topdressed with fine sand. Another common and more economical approach for establishing a putting green is to introduce hybrid Bermuda sprigs (the [[stolon]] of the grass which are raked out at the sod farm), which are laid out on the green.

[[File:Flag at Spur Valley Golf Course - panoramio.jpg|thumb|left|upright|Flagstick at Spur Valley Golf Course]]

Two downside factors of Bermuda greens are cost of maintenance, and also the existence of grain (the growth direction of the blades of grass), which affects the ball's roll and which is called "the grain of the green" and not to be confused with "the rub of the green" which are idiosyncrasies encountered getting through the hole. The slope or break of the green also affects the roll of the ball. The hole, or cup, is always found within the green and must have a diameter of {{convert|108|mm|in|2|sp=us}} and a depth of at least {{convert|10|cm|in|2|sp=us}}. Its position on the green is not fixed and typically is changed daily by a [[greenskeeper]] in order to prevent excessive localized wear and damage to the turf. A new hole will be cut by a device that removes a plug of the turf from the ground, and the reinforced cup is then moved, before the old hole is filled in with the plug cut from the new hole and levelled. The hole has a flag on a pole positioned in it so that it may be seen from a distance, but not necessarily from the tee. This location marker is officially called the "flagstick" but is also commonly referred to as the "pin". Flagsticks are made of either coated fiberglass, metal, or wood and have a metal or synthetic bottom (called a ferrule) that is designed to fit in the hole cup.

Putting greens are not all of the same quality. The finest-quality greens are well-kept so that a ball will roll smoothly over the closely mowed grass. Excess water can be removed from a putting green using a machine called a [[water hog]]. Golfers describe a green as ''fast'' if a light stroke on the ball makes it roll a long distance; conversely, on a ''slow'' green a stronger stroke is necessary to roll the ball the same distance. The exact speed of a green can be determined with a [[stimp meter]]. By collecting sample measurements, golf courses can be compared in terms of average green speed. It is, however, illegal by the [[rules of golf]] to test the speed of a green while playing by rolling a ball on it, or by feeling or rubbing the green.

The cost of installing and maintaining grass greens constitutes a considerable proportion of the expense of installing and maintaining a golf course. To save money, many low budget courses catering to casual players have sand greens instead of real grass. In recent years, [[artificial turf#Golf|artificial turf]] has also become an increasingly popular surface as a less costly alternative to grass which more closely resembles the appearance and feel of real grass compared to a sand surface.
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