Reflecting on Traditional Practice

There are many maintenance activities and management decisions which can usefully be reflected on, however we have chosen the following example because the principles are very relevant for any turfgrass surface.

Mowing bowling greens: Why the drive to cut short?
Received wisdom and tradition is that a fine, shortly mown, surface is one that is suitable for the game of bowls. This seems quite sensible and straightforward. However, an important aspect of reflection in groundsmanship is to question and challenge assumptions and actions.

This is a really important process to consider how best to manage the following, especially due to what is happening in the industry and to bowling green provision:

• Reducing numbers of experienced and well-qualified greenkeepers and grounds operatives.
• Reducing bowling green membership numbers at many clubs.
• Limited funds due to reducing or low membership income.
• Increasing costs of materials.
• Cuts to local authority budgets resulting in bowling greens often being maintained to a minimal, if not below, level or being 'farmed out' to clubs to self-maintain.
• Greater reliance on volunteers to maintain greens.

The reflective question is, "Why mow at the 'traditional' height of cut of 3/16" (5mm) and why not higher?".

Well, it's nice and short and produces a dense sward, plus it's the same as what is carried out on a golf course. This doesn't really answer the question though, so what impact does height of cut have on the distance rolled by, or speed of, a bowl, as speed is typically the main focus of discussion for many players?

If the grass was at a height of 25mm (1 inch) then clearly, we couldn't play bowls as it would be like playing in a meadow, or more like not being able to play at all. This is surely the reason, i.e. too long and the bowl won't perform; so 5mm (3/16") it is, but is there any evidence to support the question of mowing higher as a matter of routine?

For most bowling greens we want a fit for purpose surface, not a championship one with all the costs involved in providing one of those. Could raising the traditional cut height slightly still create the required desirable playing conditions yet reduce the stress put on the grass plant from shorter mowing and help counter consequences of many of the issues happening in the industry?

An added benefit will be that with reduced grass plant stress the bowling green will be more resilient, better developed (i.e. increased root development; increased density) reducing the competition from weeds and disease, as well as reducing the intensity of input. So, what does the evidence say in relation to height of cut and green speed or roll?

The context here is that we want a bowling green to provide a suitable level of playing satisfaction but within limited financial resources and reducing memberships. This might not be as big an issue at clubs with large memberships and more available monies, but it is still something all clubs should consider ensuring optimum use of resources is applied to the green.

What is the evidence?
We don't really want a particularly slow green, i.e. one which is less than 10 seconds otherwise it is going to be very heavy and difficult to have a more elegant controlled game.

We must not get too hung up on speed though: World Bowls give performance standards for a bowling green (albeit focussing on synthetics though) as between 10 and 18 seconds; so whilst 10 seconds is at the lower end it is still an acceptable speed. 10 seconds has been identified as an acceptable minimum speed, with 12 seconds being a preferred minimum (Perris, J. (2008) 'All About Bowls: The history, construction & maintenance of bowling greens', 3rd Edn, STRI, p211).

Clarification on green speed is needed as to whether the figures quoted are for a non-biased bowl used form a ramp, or a biased bowl delivered by hand. Figures are mostly quoted for the use of a non-biased bowl from a ramp, so to compare these with a more common and quicker way of testing (i.e. delivery of a typical biased bowl) then a small amount of extra time is added, 1 second can be used as a guide, so if 12 seconds is being aimed for with a non-biased bowl, then this would equate to 13 seconds for a biased bowl. (Woodham, P. 28th August 2018, 'Tournament monitoring at Victoria Park', https://strigroup.com/bowls-england-national-championships/)

Do we want a speed which is relatively fast for some of the playing season but which we can't afford to maintain and ultimately creates a poorer quality surface for parts of the season, or do we want a speed which is relatively consistent and where we can have a relatively decent and enjoyable game of bowls on an acceptable surface which we can afford to maintain?

Green speed is related to the height of the grass, but there are other factors, especially firmness, thatch content, moisture content, surface evenness and surface coverage, which affect the speed. Unfortunately, there is a strong focus on the height of the grass and limited attention to the other factors.

The type of grass which is present can affect the distance and speed of a green. A fine fescue or bentgrass species can add an additional second to the speed of a green, when compared with an (undesirable) annual meadow grass green. So, from being generally slow to slightly acceptable, the speed could increase to slightly acceptable to satisfactory (Perris, J. pp205 & 216).

If we look at desirable grass species only and consider grass height data, we can see that the average speed gain for cutting from 8mm to 5mm is 0.6 seconds (Just 10.8 seconds, compared with just over 11.4 seconds for the faster and shorter height of cut - this is just an average and a generalisation, but it illustrates the point of questioning the real gains from cutting short on a regular basis).

The data ranged from:
• 10.2 to 11.3 seconds for the 8mm cut green
• 10.3 to 11.4 seconds for the 6mm cut green
• 10.7 to 11.9 seconds for the 5mm cut green.

How much of an impact this really has to the practical bowler is dubious at best; just think about it - half a second gained. Increasing the height of cut from 5mm to 8mm for most occasions would, however, have a significantly positive impact on the grass plant, for example:

• A 60% extra in leaf area to capture energy from the sun and to help improve root growth and grass development.
•A more competitive situation for the desirable grasses, especially fescues, reducing the capability of annual meadow grass.
•Reduced fungicide applications, in principle, as the grass plant will be more stress free (from being mown too short all the time).
• Ability to withstand wear that much better.

This poses a couple of questions (at least)
1. What would the speed be if we allowed the grass to grow slightly longer in between cuts (say 11 or 12mm) before cutting it at a set height of 8 or even 9mm?
2. What impact, though, will this have on the required mowing frequency?

We know that grass needs to be mown regularly to maintain a relatively dense sward, plus it grows at varying rates from March - November, slowing to dormancy in areas from December to February, but still requiring the occasional topping. Clearly, we need to mow the green, but what frequency can we typically 'get away with' to ensure we can still play a satisfactory game of bowls on the green with limited membership, income and resources for maintenance inputs?

We don't want a fluffy green which affects the roll of the bowl, so what height can we let it grow to until we then need to mow it?

Each grass species will grow at different rates, and there are many inter-connected environmental factors which also affect growth rate: temperature, available moisture, sunlight, nutrient availability, age of grass plant, whether it has recently been 'stressed' by a mechanical operation, and more. So, giving an actual height growth is quite problematic, but we do want something to work on as a principle for our considerations.

We also need to consider how much growth can be removed each cut without being especially detrimental to the grass plant - this is typically no more than 33% (to 40%) of the leaf, so that's a helpful point we need to consider.

One reported experiment (Shildrick, J.P. 1986, 'Mowing regimes and turfgrass regrowth', The Journal of the Sports Turf Research Institute, Vol. 62 pp36-49) for turf mown at 12.5mm to 50mm saw the finer grasses grow an average of 2.8mm to 3.4mm per day over the whole season, although figures for the trials with lower heights of cut saw an average of 1.6 to 1.9mm per day. We mustn't forget that this does relate to turf allowed to grow in a trial to 25mm, which is significantly higher than for a bowling green, but at least it provides us with a general guide.

An estimate from the above data for bowls speed might indicate a further reduction in speed from an 8mm average of 10.8 seconds to maybe between 10.5 and 9.5 seconds, if the cut height was 9mm, so we are into the area of a slowish green, which we don't really want but would be generally acceptable for many situations.

If we say 2mm growth per day and have a cut height of 7mm then we could cut Monday (7mm) - ideal for some good games that need playing; grows to 9mm for Tuesday (speed = arguably a bit slow and slowing over the day) - plan for casual, general games that day; cut Wednesday (back to 7mm); same thing - cut Friday and cut Saturday for weekend. So, 4 cuts per week, at times this could easily be 3 cuts, but we would limit the maximum to 4 cuts, except for tournaments, but there wouldn't be too many of those at the type of club we are considering for this change of mowing practice. The height of cut for premier tournaments at clubs might be set at no lower than 5mm, whilst for other tournaments 6mm and normal club play and competitions 7mm.

If most greens are typically cut from 3 (minimum) to 7 times (maximum) per week, saving one cut for those cut 4 times or more, and at a slightly higher height of cut, may only be a small saving (although this may still be 20 cuts, or more), but the benefit is that considerable thought is being given to making the most of the grass surface by making the grass as competitive and as hard wearing as possible, reducing the need for other (often excessive) material inputs of fungicide, water, and fertiliser in particular. Given good greenkeeping working practices an improvement in the overall quality of the bowling green should result.

To sum up: For many clubs and greens, giving serious consideration as to what is fit for purpose for your situation can help reduce inputs yet still maintain satisfactory playing conditions ¯ don't just follow the crowd. Trying to keep up with others may not be in the best interests of your club, or green. In fact, a systematic and logical (and genuinely well-informed, in contrast to well-intentioned) approach to greenkeeping can save considerable time and money. There are numerous other maintenance activities to consider, along with the existing condition of the green, but reflect on received wisdom, traditional and current practices to determine what is best for your specific needs.