Bowling Green Mowing

Mow at a height of no less than 5mm, especially where red fescue is the dominant grass, although in some instances mowing below this height might be desired for tournament play. Whilst figures are often mentioned of a height of cut of 3mm for such situations, this is really not acceptable if the aim is to have a bowling green that has an enduring surface which gives a good consistent playing experience without the need for continued high, and costly, maintenance inputs. The aim should be to mow as high as practically possible to help encourage as deeper rooting grass as possible. During dry weather it is desirable to raise the height of cut to at least 6mm, whilst during the non-playing season the setting should be no lower than 8mm leading up to the start of the season or just after renovation, preferably aiming for a height of cut setting of 10mm-12mm.

A bowling green in early spring, prior to the start of the playing season, is in a challenging situation due to the likely variable weather conditions which seem to be occurring each year on a more frequent and regular basis.

Caution should be applied in trying to lower the height of cut too early. Cold spells, early drought, unseasonal hot spells, excessive rainfall, as well as late frosts or snowfall are all distinct probabilities. These can all have a significantly negative impact on grass growth and development. It is wise to provide the grass plant with an added insurance policy of keeping a small amount of extra leaf on during this period, typically 1mm-3mm, until weather conditions in that period of the year stabilise and are more certain to progress into a more consistent good grass growing weather.

If a green is cut during the early pre-season preparation stage, say mid-March, at a height of cut of 12mm and if, for example, there are then still 5 weeks before the first game of the season (although the start of a playing season at a club will vary) then a very gradual reduction in cutting height can easily take place.

If the weather is suitable and the club has decided on an opening height of cut of 6mm, then the following approach might be taken to achieve this without undue stress on the grass plant:
• Mid-March (3rd Week): Cut height is 12mm, with 2 cuts this week; (Sat; Weds).
• March Week 4: Cut height is 10mm, with 2 cuts this week; (Sat; Weds).
• April Week 1: Cut height is 9mm, with 3 cuts this week; (Sat; Tues; Fri).
• April Week 2: Cut height is 8mm, with 3 cuts this week (Sat; Tues; Fri).
• April Week 3: Cut height is 7mm, with 2 cuts (Mon; Weds) and then a third and fourth cut (i.e. a double cut) at 6mm (Fri).
• April start of Week 4: day 1: green to be with an opening cut height of 6mm (Saturday morning). If the season starts earlier at a club then start at one of the higher heights given earlier and follow a gradual reduction in cutting height and don’t be in a rush to reduce the height of cut to 5mm, or so.
• The following might then occur for May: Week 1 - 5.5mm; Week 2 onwards - 5mm.

During the playing season the green will be mown in a diagonal fashion, corner-to-corner. The historical reason for this was that mowers could create a track which could influence the run of a bowl as well as act as a guide to help bowlers. Modern mowing machinery has improved significantly since the 1950s and 1960s and now the only reason for mowing diagonally is that of reducing the potential aid to bowlers in delivering a bowl by using the otherwise up and down stripes as a guide. Outside of competition, or similar days, there is a good argument to mow in the direction of play rather than diagonally. This will also help to increase different mowing directions and reduce the chance of a ‘nap’ developing and will also increase, or maintain an already good, sward density. In addition, varying the location of turning on the green at the ends with the mower can help to reduce the stress put on the grass plant by the mower due to the action of turning of the rear roller.

Mowing during September, especially after the finish of any major tournaments – the last of which might actually be at the end of August – should start to see the height of cut raised gradually. Players will be starting to ‘wind-down’ regards the grass playing season and getting ready for the transition to the indoor scene.
Whilst there is typically a flush of growth during the early to middle of September, this is easily controlled by regular mowing. The grass plant will be wanting to produce food reserves to be stored in roots and rhizomes ready for the overwintering period and for the start of the following spring. Raising the height of cut helps to maximise, within practical limits, the food which can be manufactured in the green grass leaves by photosynthesis. Waiting too long until October to raise the height of cut will significantly reduce a natural process of improving the long-term health and resilience of a plant.
Consider height of cut changes from 5mm, to 6mm, to 7mm and even to 8mm during September. If an early renovation was carried out, then the top-dressing would typically cover about 1mm-2mm of the base of the sward once it has been well worked in, so even an 8mm cut prior to top-dressing would not be especially short.

Frequent mowing, at least on three occasions per week during the main growing season, is important to maintain a compact sward. Mowing on four occasions might be considered a good balance when compared with daily mowing, which is probably unnecessary in many cases and puts considerable stress on the grass plant. A green which is cut on four occasions per week might follow a routine of mowing on Monday, Wednesday, Friday and Saturday. More frequent mowing will be aimed at the more elite level of clubs and greens, which will cost more to maintain as well.

Regularity of mowing is very important if a good playing surface is to be produced. Irregular mowing frequency during the playing season will lead to a more stressed sward which will become less dense, with reduced rooting, an inconsistent draw on the bowl and a slower and less true surface. Keeping the green cut at regular intervals, without removing too much leaf growth per cut is an essential ingredient in the production of a good green.

Ideally, mowing the green will take place when the grass and surface are dry, along with no surface casts from earthworm activity. Switching or dragbrushing a green will help to dry it when dew is present and to disperse worm casts prior to mowing. Cutting blade technology and blade maintenance equipment continues to improve, and whilst a good cut can still be achieved in wet conditions, the best and most consistent cuts will be produced on a dry surface.

The use of groomers, such as light metal combs, nylon brushes, ridged front rollers, or powered groomers, are often used prior to each mowing as this will help raise up lateral growth and to control creeping weeds in particular.
Verticutting and scarification will also help to eliminate and reduce the potential for lateral grass growth. The picture below illustrates what can happen where inadequate grooming activities are undertaken on a green.

Occasionally some clubs will leave a mowing strip around the edge of the green, which is cut higher than the rest of the green. This can be beneficial at certain times of the year where the edges dry out rapidly or where the edge of the green suffers from poor stability and reduced root penetration. Part of the reason often stated for doing this is also that it helps reduce wear. However, if this is to be undertaken then it needs to be done with caution. In particular, the period of time the extra length of grass is allowed for and more importantly the frequency of mowing, which should be as the same as the rest of the green, as well as the actual cut height, which will typically be 8mm (5/16inch). If the grass is to be cut so that no more than 1/3rd of leaf is removed his will mean that the maximum growth height permitted will be 12mm. Abiding by this in practice is seldom achieved. What will typically happen is that the mowing frequency will suffer as the edge will look alright and be left until next time. The sward will gradually start to thin more than the main body of the green and also more lateral, rather than upright, growth will develop; annual meadow grass and perennial ryegrass (where present) will produce flowering stalks which will further thin the sward, and this will also lead to increased wear, so in effective there is no difference from that on the main body of the green.

Where leaving a mowing strip of slightly longer grass is used judiciously and for a specific reason and within relatively short but defined time periods then this might be a practice which could be considered. If wear is the main reason then the cause of the wear needs to be addressed rather than trying to accommodate the problem; for example, spread usage more, encourage good etiquette from players on the green, ensure adequate aeration is carried out at the edges – by hand forking if need be, especially if the aeration machinery does not adequately reach up to the edge or is too shallow in penetrating into the rootzone.

Backlap a mower on a routine basis, possibly weekly to keep the bottom blade and cylinder sharp. The required frequency will depend on the amount of use from the mower and if there is any sandy material on the sward surface, such as particles brought to the surface by earthworm casting. If a blade is damaged, or in need of annual refurbishment then a regrind of the cylinder and bottom blade to recreate an initial sharp edge can be carried out – this can then be maintained by regular backlapping during the playing season.
Grass clippings will typically be boxed off and removed on most occasions, although during hot, dry summer weather the occasional letting of clippings fly would not be detrimental to the sward and can aid protect the basal crown of the plant from intense heat.

Arguably the largest contributor to the deterioration of bowling greens is the cutting of a green too short and the consequences of this on the grass plant and sward can be considerable. Primarily there is an increase in annual meadow grass content, a reduced depth of root penetration and density and an increase in thatch levels.

With relatively high levels of thatch also being present on many greens a cylinder mower might be set at a correct cutting height of 5mm, yet once mower is on the green the weight of it will sink slightly into any thatch layer, quite easily by 1mm or 2mm, or more depending on how moist or soft the surface is. The effective cutting height can therefore quite easily be 3mm which is unsustainable if a firm, good surface quality and good paced green is to be produced.