Golf Bunker Maintenance

A uniform, firmed depth of sand of about 100mm should be adequate for the base of most (sand-trap) bunkers, with a. depth of 50mm being aimed for on the face of bunkers. The angle of the face of a bunker will typically be no steeper than 30°-35°, otherwise the ability to maintain a stable and uniform sand surface will be problematic, requiring increased maintenance.

Sand chipped onto a green, from a bunker, should be dispersed on a daily basis and especially prior to mowing. Switching the green can not only disperse any sand on the sward surface but any small stones or grit will be more easily heard when hitting the cane and these can be quickly identified and removed by hand from the green so as not to cause any damage to a mower blade.

Greenside bunkers, or the results of golfers chipping out of them, can create a problem of sand build-up on the green over time resulting in part of the green being sandier than the main body of the green. This can produce an area that is quicker drying, and which requires additional localised hand watering to complement any irrigation applied by sprinklers.

With a more rapidly drying area, the need for other work may include applications of a top-dressing material with slightly increased finer soil particles and/or material with a higher organic matter content to help better retain moisture. This would typically be applied after hollow tining the area. The use of organic conditioners, such as seaweed and biostimulants, might also be considered for these more drought prone areas.

The type of sand used in bunkers will vary, but when they are periodically topped up make sure the imported sand is compatible with the existing sand (assuming it is of an appropriate particle size analysis and shape in the first place). The particle size of the sand will be centred around 0.25-0.50mm diameter and will typically be sub-angular (to angular) in shape, as this shape will help to retain an adequate depth of sand on bunker faces. A rounded sand would not be able to provide adequate stability in a bunker, especially on the bunker face with a relatively steep angle.

Wind blow is also reduced with (sub-)angular particles, however, they are also more prone to becoming compacted and harder during drier weather, so regular raking and opening up of the sand is essential if a relatively soft and playable surface is to be produced.

The colour of the sand will typically be white to grey-white, or a shade of yellow, but it will depend on availability and the distance to procure a suitable supply. Too bright a white colour can be dazzling for players in bright sunlight.

Bunkers will typically be raked daily ensuring that if golfers encounter this sand trap then at least they have a reasonable opportunity of getting out of it; something which would be less likely in a poorly maintained bunker. Small bunkers will typically be hand raked, whilst larger bunkers might be raked with a ride-on machine with rake attachment/s to improve efficiency, although the edges of the bunker will still most likely have to have some finishing touches by hand raking.

The speed with which course bunkers can be raked using a ride-on bunker rake, for example, the Toro Sand Pro, can make this a much more efficient activity when compared with hand-raking of bunkers. This will be a significant consideration for courses with large areas of sand to rake and also those with limited staff availability. However, getting into and then out of a bunker can often result in sand debris needing to be cleaned at those locations, although this should just require a light brushing to produce a clean finish. The motion of the ride-on rake, especially where raked in the same direction can result in a rippling effect on the surface of the sand, so varying the direction of raking and even occasional cross raking by hand can help to ensure a smooth surface is maintained.

Sensible use of a ride-on bunker rake is important, which also includes operating at an appropriate and not too fast a speed, otherwise wheel spin within the bunker, as well as compaction and sand churn with tight turning circles, the rakes can bounce causing an uneven finish, and damage to the grassed edges of a bunker can occur, requiring unnecessary and often time-consuming reinstatement work to be carried out.

A well raked and presented bunker is an important part of providing a course which is a fair challenge for a golfer. Having found themselves in a sand trap it is unfair for them to then be presented with an unkempt bunker. Having arrived at a bunker the greenkeeper should first check for damage, whether rabbit scrapes, collapsed bunker faces or edges, or whether any waterlogging is present. They will try and rectify any damage either there and then or report it later on for attention.

Debris, such as stones, leaves or twigs, will be removed and then, typically, the flat part of the bunker is raked and then finished off by raking all around the edge, moving sand from the body of the bunker towards the edge and raking sand up the bunker face. The positioning of bunker rakes can be a contentious issue, so local rules need to be followed, although placing the rake on the sand and facing into the bunker with the handle nearest the edge with the rake prongs pointing downwards is one option.

The edges of bunkers will be trimmed to ensure they stay tidy, although greenside bunkers will typically be more manicured than bunkers located in a fairway or rough. The use of long-handled edging shears and strimming for routine trimming and a half-moon edging iron for reshaping might all be used as part of bunker maintenance.