Golf Green Maintenance

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Golf Green Maintenance

Introduction

Golf is played on a range of course types, from coastal links, through heathland and parkland to upland moorland, with various 'blends' in between.

The golfing season is for 12 months, with the main competition and play taking place between April and September.

A normal round of golf consists of 18 holes: Where a course consists of 9 holes, then twice around the course enables a normal full round to be played. In this latter case, different tees are typically used for the first and last nine holes.

Par 3 courses are also available, whereby the player can hit the ball directly from the tee and onto the green.

Diagram to illustrate the main features of a golf course

Golf Course Features

The writing of this Golf Course Maintenance series has involved reviewing some 20 years of recent literature to provide a useful study of the wide range of methods and practices carried out on courses.

Quality

Course presentation can reflect the level of quality achieved, although the actual quality of a course can be masked or enhanced by the attention to detail.

The Greens are the main criterion for assessing course quality and these should

provide a smooth putting surface;
consist of a uniform, dense coverage of desirable grasses;
be free of weeds and pests;
be free draining; and
be firm.

Tees should

be free from divot holes (with divots being repaired regularly);
provide a firm, even surface from which to hit a ball; and
consist of grasses with good recuperative potential.

Fairways should

provide for the golf ball to be able to be well struck;
be smooth, without holes such as rabbit scrapes;
be well defined, by mowing.

Bunkers should

have a smooth surface (by being regularly raked);
contain firmed sand to aid a players foot grip and to prevent the ball from 'plugging' too far into the sand.

Diagram to Illustrate Quality and Individual Standards

Quality and Standards

The setting of these performance standards provides a means of objectively assessing the quality of the areas on a golf course.

Most users wish to have a first class golf facility, however, the cost in materials, machinery and especially the skills of qualified and experienced greenkeepers do not come cheap. Realistically the aim is for a course which provides for a challenging game of golf throughout the year, is well presented and is managed in a cost-effective manner.

The actual maintenance cost for a golf course will depend on a number of variables, in particular the size of the course, number of greens etc., the number of staff employed, the type of course and its geographical location.

Introduction

This article should hopefully provide a general review and snapshot of greenkeeping practices. It is not intended as a comprehensive review due to the vastness of the subject.

With golf being played for 365 days of the year, the amount of potential wear on a golf green can be considerable.

Even with a typical size of a green being some 500m² wear can be concentrated around certain areas of a green, such as the pin positions or popular walk off areas.

The main growing season is the period when the course is expected to look very good and play perfectly, with the jewel in the crown of any golf course being the greens.

Care should be taken not to produce lush and coloured greens as this will be detrimental to the quality of the greens: This demand for 'attractive' greens has arguably been encouraged by television and poorly informed golfers. [1] [2]

The colour of links courses "should have a pale greenish brown colour" and should be considered the optimum for most courses. [3]

The course manager of St Andrews, in 1986, neatly summarised what should be expected of greens: "To expect perfect greens every day of the year is asking the impossible. Good greens are expected and great greens should be appreciated". [4]

Continuous maintenance, usually of the highest order, is required to ensure the desired standards are achieved. The large amount of different operations required need to be undertaken in a well planned manner if the most is to be achieved from the, usually limited, resources available.

How, when and what to undertake ultimately comes down to the decision of the greenkeeper who should be well trained and educated. "When judging the relevance or value of a maintenance practice it must be related to the local soil type and/or climate".[5]

It is no use undertaking a task that will ultimately result in a significant and accumulative deterioration of a green. Always think before acting and understand the consequences of carrying out an operation at different times of the year.

'Acid Theory'

The 'acid theory' was practised during the early parts of the twentieth century and was based on the application of ammonium sulphate and sulphate of iron to fine turf.

This practice, however, "came into disrepute in the 1930's due to over-enthusiastic applications without correcting associated aeration and irrigation problems".[6]

In America, after 1928, this practice was also questioned and "the USGA ceased to support the acid theory". [7]

During the 1980's the acid theory was often viewed as a "highly controversial, radical theory". [8]

The practice of applying acidic materials to fine turf may have started off as being a theory, however, it became an established fact that fine fescue/bent turf favoured an acidic situation more than disliked it.

The basic principles of greenkeeping were established some 80 years ago by the Rhode Island Experiment Station and considering scientific and technological developments since then, have stood the test of time exceedingly well.

The appropriate requirements for fescue/bent turf were found to be as follows:

Nitrogen was identified as the most important nutrient and the source should be acid reacting, such as ammonium sulphate.
The acid soil conditions were favoured by the fescue/bents and disliked by weed species.
Phosphorus and potassium should not be applied as a matter of course, only if there is a deficiency. [9]

Dr Murray, in South Africa, is quoted as saying, in 1912, that turf nutrition should "provide an adequate supply of nitrogen in an acid medium, with a very limited source of phosphates and potash". [10]

"The history of golf green nutrition during the subsequent years has been characterised by attempts to deviate from these basic principles, sometimes with disastrous consequences".[11]

Fine turf composed of fescue/bent has been and should continue to be maintained in accordance with the basic principles of greenkeeping founded in the early part of the twentieth century. The appropriateness of this practice was reported in a comprehensive summary of fine turf requirements carried out by the STRI in 1987. [12]

A later report, in 1995, showed that whilst the majority of greens tested in a research project were on the acidic side, a significant amount - 19% - had a pH of 4.5 or less. "Under these circumstances healthy turf development could be affected". Careful consideration would therefore need to be given in these situations as to the most appropriate materials to apply. [13]

The acidic approach has been has been shown to be the most appropriate regime in most situations, however, this must not be taken as being the only approach to take. Creeping bentgrass greens, for example, benefit from less acidic greens than typical fescue/bent greens and would require a different maintenance regime.

Blind adherence to continued acidity inputs can result in the disappointing failures that were previously mentioned that occurred in the 1930's. Be aware of the benefits of following the basic greenkeeping principles, however, monitor the situation and understand the consequences of an over-enthusiastic approach.

Mowing

This is the most important and visual operation that is carried out and is the one which provides for the finishing touches to a green. Hand mowing or ride on triple mowing can be undertaken depending upon personal choice, although both produce the very fine finished results required from a green.

Both types of mowers can readily be utilised throughout the season. The frequency of cut may be alternated between hand mower and triple mower, although this will be down to personal choice and staff availability.

Grass clippings are invariably boxed off to reduce earthworm activity and to limit the potential for annual meadow grass and weeds spreading.

Changing the direction of mowing is essential to produce an upright growing grass and not one that develops a nap or grain, which can result from mowing in one particular direction too frequently.

The finishing touches to a green can be achieved by mowing around the perimeter of the green with a triple mower or once or twice with a hand mower.

The height of cut for greens can sometimes be a contentious issue, however, a good rule of thumb is 3/16" throughout most of the growing season, being raised slightly in times of drought, with tournaments being cut at 1/8" or 5/32". The height would be 1/4" during the slower growth periods leading into and out of the winter and 5/16" over the winter period.

Cutting turf too close on a regular basis, i.e. 1/8" can result in moss becoming evident within the sward. To help provide for a more competitive grass in such situations a higher amount of nitrogen can be applied. [14]

Unfortunately this continued close mowing will encourage the development of annual meadow grass as well as all the detrimental issues that arise thereafter. [15]

3/16" appears to be the most appropriate minimum height of cut for golf greens for normal club play conditions and where a consistent fine quality turf is aimed for. [16] [17] [18] [19] [20] [21] [22]

The lowest height of cut that is usually considered for short periods of time, such as during tournaments / championships would be 1/8" to 5/32". [16] [17] [23] [24] [25]

It is unwise to suddenly reduce the height of cut for fine turf - a gradual reduction over a period of time should be carried out when considering lowering the height from 3/16" to 1/8". One of the most publicised occasions when things went wrong were at Royal Birkdale in 1991 when there was allegedly "a sudden and severe drop in mowing height and related treatments to achieve faster speeds". Such adverse publicity, however true or exaggerated, is not welcome by any greenkeeper. [26]

A typical mowing frequency during the main growing season will range from 4 to 7 occasions per week, depending upon growth activity. Following fertiliser application, mowing will be more regular than say during a drought. An 'average' frequency of cut during the peak growing season will, however, be either 5 or 6 occasions per week.

Immediately adjacent to the green is the surround - which is typically one or two cylinder mower widths (some 50 - 100 cm width) - and the apron/approach immediately in front of the green. These are usually cut at the same time as the green.

The green surround will typically be mown at 1/4" - 5/16" height of cut, whilst the apron/approach might be at the same height as the green or at a the height of the surround.

Double mowing the green, whilst increasing the overall time of the mowing operation, helps to increase the speed of the green without having to reduce the height of cut which would increase the 'stress' placed on the grass plant.

A typical programme of events for mowing greens leading up to and during a major championship, such as The Open, would be along the following lines (this assumes that the event is in the main growing season, with periods of relatively good growth either side of the event):

The first day of the championship will be called D-Day, and all the other days will be related to this.

Day	Height of cut	Frequency of cut	Comment
D-14	3/16"	x 1	A gradual reduction in the height of cut should take place
D-13	3/16"	x 1
D-12	3/16"	x 1
D-11	3/16"	x 1
D-10	5/32"	x 1
D-9	5/32"	x 1
D-8	5/32"	x 1
D-7	5/32"	x 1
D-6	5/32"	x 1
D-5	1/8"	x 1
D-4	1/8"	x 1
D-3	1/8"	x 1
D-2	1/8"	x 1
D-1	1/8"	x 2	Double cut, or x1 in morning and x 1 in evening
Day 1 of Championship	1/8"	x2 or x3	(a) if cut twice x1 in morning; x1 in evening; (b) if cut three times then: x1 in morning x2 in evening
Day 2	1/8"	x2 or x3
Day 3	1/8"	x2 or x3
Day 4	1/8"	x2 or x3
First day: Post event	3/16"	x1

[4] [16] [17] [24] [27] [28]

Turf Nutrition

The amount of fertiliser to be applied to fine turf, especially golf greens, has been the subject of much debate over the past 20 years. One view is to apply a balanced amount of nutrients to the turf on a regular basis, whilst another view, which can be termed the minimalist approach, is to basically apply only nitrogen to golf greens.

Much maligned and misunderstood by some we will look at the minimalist argument and try to piece together the different threads of this argument.

Firstly though, we should just remind ourselves that a plant needs nutrients to grow and these nutrients are obtained either from the air, water or soil. The majority of these nutrients are provided naturally without the need for any additional input from applied fertiliser or to a lesser extent by top-dressing.

Nitrogen is the main element applied in a fertiliser to a green. The amount, as well as the source, of the nitrogen can, however, have a significant impact on the sward composition.

The other main nutrients commonly applied are phosphorus and potassium. These two nutrients are a particular bone of contention in the minimalist fertiliser debate and are said to be "needed in such small amounts that the needs of fine grasses are already oversupplied". [6]

This has been a consistent theme and is actually supported over the years with documented evidence.

Leaving aside hearsay and gossip, what has actually been reported in magazines and other sources about turf nutrition of golf greens. Obviously this section can only provide a general overview, however, it should provide enough information to confirm what is required from fescue/bent greens.

The fundamentals of turf nutrition have not changed since the early part of the 20th century, just the wide range of potential sources from which to choose.

"The overall nutrient balance for turf maintenance should be around 4:1:3 to 4:1½:3; N:P₂O₅:K₂O".[29]

This can be supplied either from the soil/organic matter, air depositions, top-dressings or fertiliser applications. Significant quantities of nutrients can be found within the soil profile of golf greens.[30]

The innovations made by fertiliser manufacturers, such as controlled release fertilisers which can be usefully employed on very high sand content facilities (especially football pitches and creeping bentgrass greens), or the ready availability of different balanced fertilisers which have a longer storage life than home made mixtures, has certainly assisted the greenkeeper in having a wider choice from which to select for their specific situation. [31]

Unfortunately this has also lead to confusion in some cases over what to apply and when to apply it. With improved marketing skills we also see amateurs, such as golfers influencing greenkeepers to 'go along with what this other course has used' even though the greenkeeper knows it is not the solution. We need "grasses working for the keeper of the greens instead of him working for them". [32]

A balance needs to be made between the amount of fertiliser to apply to produce the 'ideal' golfing turf and enough to maintain a good sward coverage with the ever increasing usage demands being made on golf greens. We should not automatically assume that good golfing turf cannot be achieved with medium-high usage levels, although this is what is typically implied.

Providing a source of available nutrients to a green does not necessarily provide the perceived benefits of a better green. "Rapid growth is not vital to quality in terms of the turf's ability to withstand stress". [33]

Liquid nitrogen fertiliser can easily encourage rapid growth, which is far from ideal. Careful consideration to the quantity and frequency of such applications should always be given. [34]

NPK autumn fertilisers can readily encourage disease and annual meadow grass and should not be used in the majority of cases of 'normal' as against sand only constructed greens. Forced sappy growth would be encouraged at a time when the natural cycle of a plant is to harden itself ready for winter. [6] [11]

"On soil-based greens, in general, no phosphate or potassium is required other than that which occurs in small amounts in top dressings, nitrogen fertiliser being adequate." The results of following routine applications "of compound fertilisers on golf greens which, combined with overwatering, will lead to Poa annua sponge puddings". Not a statement from an inexperienced person, but by the Chief Executive of the Sports Turf Research Institute in 1996. [35]

By way of a contrast, indications of the requirements of sand constructed greens were earlier given in 1992 and summarised as follows:

Nutrient / Requirement	Comments
Nitrogen	250 - 400 kg/N/ha/yr N.B. Soil based greens would be half this rate, or less.
Phosphate	There would only be "problems at less than 10 ppm of P₂O₅". The recommended amount of phosphate to apply in such circumstances would be low, being given as less than 25 kg/ha/yr.
Potassium	The application of this "didn't have a significant effect".
pH	This became very acidic, with some readings being below pH 4.0.

[36]

Reports from an earlier trial on pure sand for fescue/bent turf had also indicated the following:

A minimum Nitrogen application of 250 Kg/N/Ha/Year
The ratio of N:P₂O₅ to be less than 4:1
The ratio of N:K₂0 of 4:3 is adequate.

[37]

The core fertiliser of 8:0:0 (inorganic/organic blend) has been described as "perhaps the greatest influence on maintaining fescue/bent turf". [38]

The use of chemical soil analysis is generally held to be of benefit in enabling greenkeepers to have suitable information from which to make informed decisions for a management programme. Whilst much can be ascertained from a botanical and physical soil analysis, a chemical soil analysis can provide just that extra bit of information that can confirm an appropriate course to take. Even some people who have reservations about chemical analysis use such results to confirm their position. [39]

The occurrence of greens tested each year by the STRI, with less than 10 ppm of phosphate levels is very small.[40] [41]

This is the level at which fescue/bent is generally satisfactorily supplied with phosphate. Unfortunately the ADAS scale, which is used as a general reference, is misinterpreted as being very low at this level. It may be for lush agricultural grasses, for which the scale was originally devised, but it is quite suitable for fescue/bent swards.

Phosphorus is an essential plant nutrient, however, it is the relative amount that is available from the soil solution that is a significant factor in deciding whether annual meadow grass will be able to colonise freely or not at all.

One suggestion has been made that an application of "phosphorus should only be made if soil levels fall below about 20 mg l ^-1". [42]

It should also be noted that much lower levels, 2 and 3 ppm, of phosphorus have been shown to be satisfactory for creeping bentgrass growth. [43]

Another report observed a deficiency of a fescue/bent green when P₂O₅ was less than 7 mg l ^-1. [44]

A report in 1995 of a survey of golf greens found that within the top 10-90mm of the green profile, 21% of the greens had values that were classed as very low ( i.e. 0 - 15 mg l ^-1). [45]

In these situations it would be prudent to have a regular monitoring programme of soil tests along with a more intensive analysis of the sward to see how species content may fluctuate throughout the season.

The above figures are interesting considering that 10 ppm of phosphate was suggested for adequate growth of fescue/bent turf for at least some ten years previously. However, as this was suggested by a consistent adherent of the minimalist approach this was arguably ignored or ridiculed by many. [46]

A paper was presented at the 1988 National Turfgrass Council's Workshop on Turf Nutrition that included a calculation into how long nutrient supplies would theoretically last, based on some contemporary research figures. This showed that phosphorus supply might last from 1 to 23 years and potassium from ½ to 6½ years depending upon the amount of clippings removed per annum. Soil reserves were not considered within the calculation and this would have a significant impact on the length of time before actual nutrients would be used up and this would also be more pronounced in an established green than in a newly establishing one. This highlights the need for careful monitoring of soil nutrients and sward content to assist in providing useful and appropriate information for individual situations, instead of trying to rely on 'guestimates' from such theoretical calculations. [47]

Acidic soil helps to lock up phosphate and this in turn is the 'base line' from which good golfing turf is made. The amounts of available P (or P₂O₅) will vary with each situation. It probably isn't all that helpful trying to state a specific figure due to the wide range of soil types, pH values, time of year and condition of the grass etc. that can exist. However, the emphasis should be on very low levels of available P, that are monitored on a regular basis, say every 1 to 3 years depending upon circumstances. This would also be complemented by a botanical analysis of the sward to indicate the species content and over a period of time this would also provide an indication of the dynamic nature of a grass sward.

Potassium levels should be maintained at a suitable level on USGA greens and sand greens due to the leaching potential of high sand profiles. [48]

If an improved colour is required during the autumn / winter period, then an application of either sulphate of iron (typically at 4 -6 g/m²) or a commercially prepared liquid iron (at around 15 kg/ha) can be used.[49]

Conclusion for turf nutrition

There is no 'silver bullet' fertiliser for golf greens - there is just too much diversity of course type, geographic location, climate, age of green and impact of usage to name some significant influences. Emphasis should, however, be made in following the established basic principles of greenkeeping.

For further information on turf fertilisers, refer to Turf Fertilisers and Fertiliser Programmes.

Switching / Brushing

The removal of dew in the morning is an essential part of any routine maintenance programme. Whether or not the greens are to be cut, dew should nearly always be removed, normally with a switch (basically a cane attached to a pole).

A brush attachment to a cushman, or similar unit, can also be used to remove dew, however, despite the reduction in time taken, tyre marks can be quite noticeable, especially on thatchy greens which can affect putting smoothness for a variable period of time after the brushing operation has been completed.

Dew left on leaves can encourage disease attack and is the main reason why dew removal needs to be carried out as soon as possible. Disease would otherwise spread rapidly amongst the moist leaf blades if conditions were right.

Aeration

Possibly the second most important operation after mowing, as the amount of usage that takes place on modern golf courses exerts a higher amount of compaction than would have been experienced many years ago.

Aeration regimes have to be adapted to suit local conditions - there isn't much point aerating a green if all that is going to happen is surface and subsurface smearing. Consider the importance of aeration and use the wide range of machinery and equipment available to best effect for each specific situation. There is almost bound to be something to suit most circumstances.

Regular aeration throughout the autumn and winter periods, varying from weekly to fortnightly intervals, will mostly be with slit tines, whilst during the spring and summer periods it will mostly be with solid tines.

Hollow tining may be considered around renovation time if conditions were deemed necessary: Typically this would be in March/April or September/October. Micro-hollow tining using 1/2" or so tines, is something which has also been carried out during the growing season. [50] [51]

Intensive deep (or appropriate) aeration, which is varied to prevent an aeration pan being formed, should be undertaken to maintain soil structure and a relatively open soil profile. Weekly aeration at alternate depths (100mm and 150mm) can be useful in combating surface compaction. [52]

Where thatch has been a problem, combined slit and hollow-tining, supplemented with regular top-dressings has been shown to be of benefit. [53]

Hollow-tining is particularly useful for soil exchange, thatch removal and for the introduction of soil ameliorants.

Aeration is an essential component of not only maintaining fescue/bent swards but also for increasing the sward content of these species at the expense of annual meadow grass. Even in three years of such work, positive effects can be seen when poor annual meadow grass greens have been addressed. [54]

Vertidraining, or similar deep spiking, is an operation which is particularly suited to helping alleviate deeper seated compaction when soil conditions are moist enough to allow adequate tine penetration, yet will also permit adequate shattering of the soil profile if required. It is unlikely that vertidraining would be carried out more than twice in any one year, with yearly to every other year being typical. [46] [55] [56]

Water injection, such as the Toro Hydroject, can be particularly suited to use in the summer months and especially where Dry Patch exists as it helps to force water into the soil profile and doesn't run off the surface.

Compressed air injection is another form of aeration which can also be suited to deep seated compaction, whilst powered drills can also be useful on localised areas of compaction.

Approaches and surrounds should receive similar attention as the greens. [57] [58]

Scarification

This is carried out on a regular basis throughout the growing season, when the grass is growing strongly. Mounted scarifiers are the norm, although hand mechanical scarification may be more suited to slopes and awkward edges near bunkers.

The frequency of scarification will vary considerably depending upon the amount of existing thatch, type of grasses present - whether stoloniferous growth or tufted annual meadow grass - and how much verticutting and grooming is taking place as well.

Monthly scarification, in general, should be the starting point from which to adapt a maintenance regime, with it being unlikely to occur more frequently than on a fortnightly basis.

Verticutting and Grooming

Verticutting will typically take place weekly when growth is strong, to fortnightly when it is not so strong, with grooming maybe twice or three times a week.

Grooming could be carried out with verti-groomers or even wire combs or brushes attached to the front of mowers.

With wire combs or brushes, grooming might be carried out with each cut (except in droughty conditions) and is particularly useful in controlling lateral growth.

The groomer height would be adjusted according to grass growth so as not to cause undue stress on the grass plant.

The actual frequency for both operations can, however, vary considerably.

Verticutting prior to top-dressing is beneficial in helping the eventual incorporation of the top-dressing as well as any applied materials such as seed or fertiliser.

During a major tournament the last verticutting would typically take place two weeks before the event.

Some greens may even be verticut in February "to clean them off" although this would not be the norm. However, for this situation it will have been deemed necessary and highlights the need to consider how to respond dynamically to an individual situation. [59]

The regime for grooming, verticutting and scarifying will and can vary considerably, however, the relative frequency will be grooming more than verticutting which in turn is more than scarification.

Overseeding

During renovation, the greens will usually be oversown with a suitable grass seed mixture. The exact mixture will depend upon local circumstances, although the species will invariably consist of the following:

Chewing's Fescue,
Browntop Bent, - both Common and 'Highland' although the latter is often replaced by the 'Common' browntop because of it having a finer leaf blade and higher shoot density;
Slender Creeping Red Fescue (2 subspecies available);
Creeping Bentgrass - mainly confined to the South of England and high sand specification constructed greens, although there is much debate as to the suitability of this species regarding cost-effective maintenance practices, as well as to the British climate;
Velvet Bent - this has recently been reintroduced with the cultivar 'Avalon' (first appearing in the STRI Turfgrass Seed 1998). The last time another cultivar of velvet bent appeared in this publication was in the 1989 issue and was called 'Kingston'. This was withdrawn due to its habit of excess thatch production etc., something which is said not to be as pronounced with Avalon.

A general mixture for a golf green might consist of the following:

40% Chewing's Fescue
40% Slender Creeping Red Fescue
10% Common Browntop Bent
10% 'Highland' Bent,

although there are wide ranging permutations to suit a greenkeepers needs.

A typical application rate will be 17 g/m², or 1/3 ^rd of a 25 kg bag per 500 m² green. This rate will supply about 60,000 seeds per m² (if we estimate :1000 seeds per gram for the fescues and say 13,000 seeds for the bents: 80% x 17g x 1000 = 13,600 fescue seeds and 20% x 17g x 13,000 = 44,200 bentgrass seeds per square metre; although individual cultivars can vary quite considerably).

Some areas of a green may require a higher application rate, maybe around some pin positions or walk off areas, but this figure should suffice for most of the green area.

Creeping bentgrass

The use of creeping bentgrass on golf greens has made an impact since about 1989, with the use of Penncross at the East Sussex National golf course. This species had been tried before, for example in about 1975 it was used at Southwood golf course in Hampshire and only lasted a few years before being replaced by other species. [60]

The disadvantages of creeping bentgrass are said to be that it

has severe winter dormancy,
can 'pluck up' badly with use,
is a high thatch producer,
is more disease susceptible than 'traditional' species.

[61] [62] [63] [64]

In 1990 an article appeared in Amateur Golf titled, "STRI Agronomists express severe doubts on the use of Penncross species in Britain". Despite developments of improved cultivars of creeping bent, the message on the whole holds true today, 'they are unsuitable for the majority of golf'. [64]

One agronomist, however, has said that if the soil conditions are unsuitable and combined with inappropriate maintenance, then the species will obviously suffer. If, however, it is "properly cared for it can be as aggressive as any improved strains of bent grass or fescue".[65]

Where high specification greens, usually to USGA standards, have been constructed and with budgets to match, then very good facilities can be provided. One only has to look at some of the courses with all or some of their greens with creeping bent grass: The Belfry, Wildwood GC, Collingtree Park, The London GC, The Oxfordshire GC, Loch Lomond GC, Hanbury Manor, Dartmouth Golf and Country Club, Wisley GC and East Sussex National as already mentioned.

Such facilities, however, cannot be said to be representative of the vast majority of courses within the UK.

One course manager of bentgrass greens states that "to keep on top of thatch build-up..... an aggressive programme of hollow-coring, slitting and verticutting" is carried out. This indicates the increased level of maintenance that will be required for such greens. [66]

The increasing maintenance requirements of such greens are also identified by another course manager who states that with the higher nutrient requirements on these greens there is a corresponding "increase in the frequency of cultural operations like verticutting, aeration and top-dressings, necessary to counteract its associated level of thatch production". [62]

Annual meadow grass is also hand picked on many of the creeping bentgrass greens. An operation which is surely out of the reach of the majority of course managers - they just do not have the staffing levels to cope with such demands. Annual meadow grass can become well established in creeping bentgrass greens, with one course reported a content of "22 to 24%" on four of its greens.[67]

Staffing levels on courses with creeping bentgrass greens can typically be 20 staff (8 seasonals) in the summer reducing to 12 staff in the winter. All this for an 18 hole course. A 'typical' UK course of 18 holes will probably have 5 or maybe 6 staff throughout the year. [68] [69]

Whilst creeping bentgrass greens can be successfully maintained to produce very good conditions, a number of salient points need to be considered before embarking upon such ventures:

The South and warmer micro-climates are the preferred locations for such greens,
Construction costs will be higher as specifications will be more critical,
Maintenance inputs are higher requiring more materials, machinery (at least servicing requirements), staff and salaries. Typically this will be in the order of x2 or x3 of the typical golf course, so we are not talking just a few thousand pounds.

For the majority of course budgets, these considerations will be unrealistic and would not provide value for money. For those aspiring to more show piece type courses and who will have, and can maintain, an affluent clientele then these greens can be a serious proposition. The final question would have to be 'Why bother'? especially when the view held by the Royal and Ancient in their report 'The Way Forward' is as valid today as in 1989 "...as an ideal surface on which to play year-round golf, fescue/bent turf cannot be surpassed". [70]

Poa supina

This is a recent introduction from the late 1990's, however, it is debatable whether this is a gimmick with potentially catastrophic consequences (being similar to Poa annua) or if it will actually be a useful option available to the greenkeeper. Poa supina first appeared in the STRI Turfgrass Seed 2000 and was given comparable performance ratings to smooth-stalked meadow grass. [71]

Velvet Bent

The STRI reported, in 1997, on the Velvet bent cultivar 'Avalon' that "Historically velvet bents were available but used to go dormant in the winter. This one does not do that. It overwinters very well". [72]

A year later a golf course that trialled the grass reported that the initial use of this cultivar had been a success. [73]

Current research has also compared the qualities of different bentgrasses, with 'Avalon' comparing favourably with browntop bent cultivars. One note of caution is that the shoot density of 'Avalon' scored highest and this could have negative impacts from a maintenance perspective, e.g. increased thatch potential and grain control. [74]

Where conditions are damp and relatively enclosed, such as being close to or partially surrounded by trees, then this species may be considered as a component of a seed mixture when overseeding.

Seed treatments

A number of companies offer seed coatings to help improve the viability of grass seed.

'Fortiva' has been offered since 1996 (initially by Force Limagrain, then Nickerson UK). This coating "contains three fungicides and a biostimulant" and is said to help reduce the potential for disease attack and improve initial establishment rates. [75]

Current research has also reported positive benefits of such treatment, showing both increased live ground cover and shoot density for a fescue/bent sward. [76]

Mommersteeg (now Advanta Seeds) launched an improved version of its 'Headstart' biostimulant treated seeds in late 1996 and this also contained increased amounts of nutrients. [77]

On the whole though, good initial reports were made for both treatments and there has been a gradual increase over the past 5 years in the number of suppliers that offer treated seed over a range of seed mixtures.

Top-dressing

To maintain a fine, even playing surface throughout the year, it is essential to apply a sandy top-dressing, ideally composted to introduce a small amount of fresh organic matter.

Typically greens will be top-dressed in both spring (April / May) and autumn (September), however, a light top-dressing applied on a monthly basis throughout the growing season would also be considered beneficial.

To ensure a quick incorporation of the top-dressing into the sward, which will keep the greens in as playable condition as possible, make sure that not only is the green surface in a dry condition, but the top-dressing itself is also dry.

Applying top-dressing on a sunny day with a light wind will ensure it drys quickly and will be able to be worked into the sward that much easier.

A drag-mat will rapidly incorporate the top-dressing into the sward once a uniform coverage has been given.

If we take a golf green to be 500 m² in size and an application rate of 1.5 - 2 kg/m², which works out as a depth of around 1mm, the total applied to a green on each application will be 750 - 1000 kg.

Heavier applications will most likely be given if the green has been hollow-tined or vertidrained.

A green which is hollow-tined at 50mm centres, using 18mm diameter tines will remove some 10% of the surface area. By contrast 12.5 mm diameter tines at 50mm centres will remove some 5% of the surface area.

Wetting Agent

Greens that are prone to drying out and exhibit conditions of water repellency may benefit from an application of a wetting agent.

Dry Patch has been shown to be a significant problem on golf courses, of all different types (Parkland, Heathland and Links) throughout the UK. The majority of courses in a survey reported that the detrimental effects of Dry Patch was reduced by the application of a wetting agent, however, very few (3%) said that complete control was achieved.[78]

Typically a programme of applications, commencing in March and continued over the summer period is undertaken to maintain the affected green, or part of it, in a condition which can readily absorb water.

The underlying cause of the drying out should be investigated, as poor root growth combined with a high thatch and annual meadow grass content may be contributing, in a significant way, to the problem.

Ideally, aerate before applying a wetting agent and water in thoroughly to prevent leaf scorch.

Diseases

A number of diseases can pose a problem to the greenkeeper and each may need to be treated in a slightly different way.

Whenever chemicals are used make sure that they are handled and applied in accordance with the manufacturers instructions, in addition to complying with any relevant legislation.

Good greenkeeping practices should be applied throughout the year to provide as resilient and disease resistant surface as possible. This will include such things as switching at an appropriate time, maintaining an upright grass and removing decaying surface vegetation by scarification and associated practices. An integrated approach needs to be taken to maximise the desirable grass species content and minimise the amount of annual meadow grass. This will help to reduce dependence on chemical applications, although they will still form an important part of a greenkeepers armoury.

Individual diseases will be dealt with in separate articles.

Weeds/Moss

Weeds present in a green produce a blemished surface which is not only aesthetically unattractive but will also affect the putt and roll of a golf ball.

Broader leaved weeds, such as plantains, dandelions and daisies should not be allowed to become established within any green. As soon as a weed is noticed it should be removed by hand. A golfers pitch mark repairer, with the prongs bent slightly inwards, is a simple, yet effective tool in prising these weeds from the turf.

Finer leaved weeds, which would include yarrow, parsley piert, pearlwort, clovers as well as toadrush, will be more of a problem. Mechanical control by scarification and followed up with mowing can help to weaken the ability of these weeds to colonise other parts of a green.

Normally this would not be sufficient to eliminate the weeds and a suitable selective herbicide would be needed to provide the finishing touches in eliminating them altogether. Some of the more persistent weeds may require more than one application of herbicide to achieve good control.

Lawn sand may be considered where weed infestation is not too diverse and this will help to reduce the reliance on synthetic hormone chemicals being sprayed onto golf courses.

Pests

Whilst the likes of rabbits, moles, foxes, birds and chafer grubs cause sporadic damage to turf, these are not usually the most significant pests: This honour lies with earthworms and leatherjackets.

Earthworms, whilst being beneficial in maintaining and improving soil aeration, as well as the effective recycling of organic matter, can be a major problem at certain times of the year when ground conditions are moist and mild. The surface casts produced by some earthworms can not only interfere with play and maintenance operations but can also lead to a deterioration of the playing surface, resulting in a surface that is prone to weeds, disease and annual meadow grass invasion, as well as being unattractive to look at.

Since the demise of chlordane in the early 1990's, the chemicals available to control surface casting earthworms have only given limited and relatively short term control when compared to the effectiveness and persistence of chlordane.

The environmental disadvantages of this organo-phosphorus pesticide necessitated its withdrawal from use. This has made greenkeepers rethink some of their strategies and revert back to preventative measures of earthworm control, such as using acidifying fertilisers, sulphate of iron, increased aeration and sometimes grittier top-dressing in hollow-tine holes.

Leatherjackets can be particularly troublesome where a significant thatch layer exists. Regular aeration, especially prior to chemical application - usually in the autumn - would help to improve the effectiveness of the chemical.

Thatch control and removal can therefore be a positive activity that can be undertaken to help reduce the potential for leatherjacket infestation.

Irrigation

Whilst grass needs to be supplied with water to survive, especially under combined conditions of dry, hot weather and heavy usage, the amount of water that is needed can be easily overapplied to maintain a greens appearance due to the ease of use of automatic pop-up irrigation systems.

The quality of golf greens is a reflection of the high content of the finer turf grasses, not the colour of the sward.

Water requirements for sports turf grasses are typically assessed as being some 25 mm per week during the growing season, part of which is received from rainfall, with the balance being made up by irrigation.

This can only be a guideline and the actual amount of water required will need to be carefully determined if a golf green is to maintain a good quality sward without becoming prone to excessive drying out from under application, or too soft from over application. Use the minimum amount of water possible to produce the desired surface - this is always easier said than done.[16]

A PGA Guide to the Tournament in 1985 made a very pertinent observation about irrigation, in particular over-application which ".. is bad for the long term health of the turf. Soft greens do not reward the skilful shot over the inferior". [79]

Inappropriate irrigation of greens can ultimately lead to target golf, which is the opposite of skilful golf. If we want to be able to succeed as a nation of golfers, good firm greens need to be produced the whole year round. Short term tinkering to produce holding greens to satisfy the whims of some poor golfers should not be entertained. Educate golfers to the needs of a good golf green and encourage them to enjoy the benefits of a skilful game, with a fair amount of sportsmanship thrown in. [80] [81]

With apparent changing climate patterns, the greenkeeper may also need to consider adapting their irrigation practices accordingly. This is an area where the wide ranging practices that are carried out in the USA may benefit from a detailed study. The need for adaptation was considered back in 1985, however, in a slightly different context before the increasing and noticeable evidence of climate change became more pronounced. [82]

Greenkeepers would find it beneficial to monitor, assess and evaluate the micro-climate for their own golf course to decide whether practices that may have been suitable some 20 years ago are still relevant today.

For further information on irrigation.

Rolling

Heavy rolling is not a requirement of golf greens. Occasional light rolling, in addition to all the rolling that takes place when the greens are cut with cylinder mowers, is sometimes carried out prior to major tournaments, or following verti-draining if surface heave has been unacceptable, or in the spring following frosty weather.

This operation should really be seen as a minor consideration in the greenkeepers armoury, but one that can be usefully applied if conditions dictate.

Hole Changing

Regular changing of the pin position is needed to prevent undue wear occurring around the current pin position. Typically the pin position will be moved on 3 occasions per week, but this will really depend upon the time of year as well as the amount of use the green is being subjected to. During tournament play the pin position will usually be moved on a daily basis.

Care needs to be taken to ensure the hole changing equipment is maintained in good conditions, especially the cutting blades which penetrate the rootzone. Damage to the immediate surrounding part of the green can occur if holes are changed in a lackadaisical manner.

Selecting a pin position and taking into account future positions for competition play needs careful thought. Try and ensure that most or all of the available pin locations are utilised before returning to the one which was at the beginning of the hole changing cycle.

Green Damage

Any damage done to the green should be repaired immediately. Small areas of damage may be able to be repaired by careful prising of the turf, a light forking, top-dressing and overseeding. More severe damage will most likely be repaired by removing the damaged turf area and inserting a new piece of similar turf, ideally grown on site in a turf nursery.

Hydraulic oil, or similar, damage might be repaired along the following lines:

Soak up as much of the oil as possible;
Fork the area and apply wetting agent; This will help to disperse any oil residue;
Consider applying a biostimulant, if in the growing season;
Consider applying a light fertiliser application, if in the growing season; Scorched tissue will be able to be removed more quickly;
Lightly top-dress and seed the area;
Apply camouflage by the way of grass clippings. These may need to be swept up and replaced every few days;
Keep the pin position away from the damaged area;
Returf small strips, although blending in may be a problem;
Excavate heavily contaminated soil, if appropriate.

[83]

Green Speed

A stimpmeter can be a useful means of assessing the speed of a golf green. The USGA guidelines for green speed are as follows:

Championship Play

Fast 10' 6"
Medium Fast 9' 6"
Medium 8' 6"
Medium Slow 7' 6"
Slow 6' 6"

Regular Membership Play

Fast 8' 6"
Medium Fast 7' 6"
Medium 6' 6"
Medium Slow 5' 6"
Slow 4' 6"

Normal stimpmeter readings in the UK fall within the range 1.6m - 2.8m (5.25' - 9.2'). An upper limit of 3.0m (9.8') has been suggested, otherwise "long term consequences on the quality of the putting surface would result".[84]

Various maintenance practices can be adjusted to improve the speed of a green without the obvious one of reducing the height of cut to an unacceptable level.

Increased mowing frequency, verticutting, a light rolling, regular top-dressing for a smoother surface, leaner surfaces by controlling fertiliser inputs and dry surfaces can all help to maintain and improve green speed. [85]

Golf Green Maintenance

Introduction

Quality

Introduction

'Acid Theory'

Mowing

Turf Nutrition

Switching / Brushing

Aeration

Scarification

Verticutting and Grooming

Overseeding

Top-dressing

Wetting Agent

Diseases

Weeds/Moss

Pests

Irrigation

Rolling

Hole Changing

Green Damage

Green Speed

References

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