In this article we take the soil samples you removed in Fix your bowling green Step1 and look more closely at them to discover what's going on under your green. This is one of the most valuable practices that any greenkeeper can undertake as it can reveal a wealth of information about the condition of your green that you could previously only guess at.
Towards the end of every bowling season thoughts start to turn to the autumn renovation program or the “closing of the green” as many clubs call it. Bowling clubs throughout the UK will take delivery of between 3 and 10 tonnes of very expensive top-dressing compost, which will be applied to the green after hollow tining or some other aeration operation, in the belief that this will ensure that the green is in perfect condition next season. However, too much top-dressing can actually harm the green and in many cases, clubs simply shouldn’t be doing it at all…but why?
The answer is simple yet full of complexity. At it’s most basic, the answer is that excessive use of sand on bowling greens causes the under lying soil to become inert; lacking life or the complex web of interactions that go to make healthy, high performance turf. The natural balance of the soil/turf ecosystem is upset and the green will never be capable of consistent high performance for as long as the folly of top dressing is allowed to continue.
The complexity comes in when we start to consider that top dressing is recommended by most experts and consultants and that this advice is religiously followed by the vast majority of bowling clubs. However, a brief look at the facts facing many bowling greens after decades of this type of maintenance makes it perfectly clear that top-dressing is not a good option for the majority of bowling greens in the UK.
In the remainder of the article I want to explore the issues I have experienced with greens that have been routinely top-dressed using high sand top-dressing composts over the past 30 years. I will explain the problems with Localised Dry Patch, Thatch, Soil Exchange, Green Levels and Surface Smoothness, Irrigation and water
management and the dilemma that all of this leaves many clubs facing.
So lets’ start with Localised Dry Patch or LDP.
Localised Dry Patch
Over the last 20 years Localised Dry Patch (LDP) has become a major problem on bowling greens, and although this is not wholly attributable to top-dressing, the excessive use of sand in the top-dressing mix has caused water retention problems on a lot of greens.
It is of course desirable to have a free draining soil profile on a bowling green to help to encourage deep rooting of the grasses and to maintain a reasonable green speed for play. However, continued application of bulk sandy dressings is of limited benefit to most greens and actually harmful to many due to their already high sand content and related lack of soil microbial activity.
Natural plant decomposition results in a release of nutrients from dead plant material, but soils low in microbial activity tend to suffer from a build up of organic material (thatch) at the soil surface, which will become much more water retentive than desired. However, the answer to this does not lie with dilution of the organic layer with huge amounts of sand, but rather in reducing this layer through judicious and very regular aeration and core removal and the ongoing encouragement of soil microbial activity.
Where the soil is less than perfect for fine turf production, soil exchange programs consisting of hollow tining followed by top-dressing with a more desirable growing medium will still be required, but this is an entirely different subject.
Green Levels versus Surface Smoothness
There is a great difference between “Surface Smoothing” and “Surface Levelling”. Surface smoothness in this context relates to very minor discrepancies in the surface which can be rectified by a combination of surface aeration, rolling and light top-dressing.
Surface levels on the other hand cannot generally be greatly improved through even “Heavy” top dressing work. This term relates to much more severe changes in level which can be measured by laser survey and can be seen to have a visible affect on a wood’s traverse across the green.
“Heavy Topdressing” usually defined as dressings over 6 tonnes will not have a dramatic effect on surface levels and are more in keeping with the type of operation required by new greens for the first 2 to 3 seasons to achieve the final levels not ironed out during construction.
I say this because if you do the calculations, a 10 tonne dressing over an average green (1400 m2) will result in a maximum coverage of 4mm, which is only suitable for smoothing out the smallest of imperfections.
By far the biggest culprit in poor levels is excessive thatch which moves, swells, compacts and contracts continually. Trying to keep up with this with top-dressing is futile.
Going back to the main issue of greens drying out, the average bowling club in the UK is finding it difficult to find the money to irrigate the green sufficiently during dry weather. Again when we look at the numbers, the average automatic irrigation system throws out approximately 1mm of water for every 2 minutes of run time.
Now I visit a lot of bowling clubs and I know that many of them rely on “rule of thumb” measurements like 4 minutes per head etc when timing irrigation. Well, on average a green will lose 25mm of moisture to evapo-transpiration (a measure of the combined effects of soil evaporation and plant transpiration) and that’s from a healthy green in a normal dry week. This doesn’t take account of excessively high sand content, drying winds or existing dry patch problems etc.
To simply replace the moisture lost from one day’s evapo-transpiration you need to run your irrigation system for 8 minutes per head, that’s double and in some cases several times what many clubs are doing. Over a 7 day period this equates to 50 minutes of run time per head.
Turning back to Localised Dry Patch. This is a condition that causes large sections of the green surface to turn brown due to lack of moisture. No amount of irrigation will make these areas re-wet. They are literally hydrophobic or water repellent. Careful use of wetting agents and hand watering can make some improvement, but usually it takes a wet winter to bring about full re-wetting. The main trouble with LDP is its tendency to make the green bumpy. This happens when the baked dry thatch layer on top of the soil starts to shrink below the surface of the surrounding healthy turf. Irrigation makes the problem worse as the healthy areas grow more and the dry areas recede further.
To crown it all, continued heavy use of the irrigation system in the desperate effort to bring these areas back to life, starts to encourage thatch fungus, which eventually sinks and causes an even more uneven surface.
The Performance Bowling Greens program isn’t completely anti-top-dressing, but I have found that very few greens, at least in the UK, can actually cope with the damage that would be inflicted by applying more sand. The program recognises that some greens will still require top-dressing and gives advice on this.
However, the most important aspect of the programs I recommend for most greens is that they focus on returning bowling greens to healthy, living eco-systems that are not only disease and pest resistant, but also in a condition that helps the club to provide their members with a consistently high performance playing surface that can be set up predictably over the entire playing season.
The Performance Bowling Greens Program is set out in comprehensive detail in Performance Bowling Greens, a practical guide.
It's hard to believe that a bowling club could easily save £1800 in greenkeeping costs every year whilst actually improving the green. Do nothing greenkeeping is my name for this phenomenon and I estimate that 98% of UK bowling clubs could benefit from it, starting this year.
Over 37 years of greenkeeping and teaching greenkeepers I have come to notice that bowling green performance comes down to just 3 major characteristics. Sounds easy then, doesn't it? Well it actually gets even easier when you identify the one key problem that contributes more to poor bowling green performance than any other.
One of the easiest, cheapest and effective methods of killing moss in turf is to apply Ferrous Sulphate. Therefore, on Bowls Central, I could sell many tonnes of Ferrous Sulphate at a nice profit margin every year by simply pandering to conventional thinking, but you won't find any for sale here. Let me explain why:
Greenkeeping Tasks for September and October have become to some degree a bit repetitive. This would be fine if the desired results followed, but in the majority of cases this can't be said to be true. This month John explains the science behind the perfect autumn renovation plan to get your green started down the road to consistent high performance.
A very general title for today’s article, but it reflects the current industry desire for a fix all solution to achieving a good bowling green.
Most clubs are unhappy to some extent with the performance of their bowling greens.
This leads to an open ended search for solutions where the searcher i.e. the bowling club or bowling club management official simply looks for information from whatever source to help with the perennial problem of the bowling green.
If this is you, if you simply don’t know where to start in your quest for the truth about achieving a consistently good bowling green here is my suggested reading in order of importance. You can click on these links for more in depth information:
Have you ever played a great game of bowls when everything on the green was perfect; you read every twitch on the rink and it seemed like you had finally got the green the way you wanted it.
The disappointment when you return to the green the very next day, prepare the rink in completely the same way but get totally different and inferior results is maddening.
What went wrong? or maybe what went right?
Like green speed, there is much debate about surface consistency, both in terms of consistency across the green surface and consistency of playing conditions over the season.
In order of their impact on green surface consistency these are the top 7 factors that you should bear in mind. Obviously there are others such as weather patterns, level of play etc, but these are largely out of the greenkeepers control and in any case do not figure highly in the management of green consistency.
- Fertiliser Policy; yesterday we talked about the role that Bio-Liquid fertilisers can play in producing Performance Bowling Greens. The use of these products is recommended primarily in order to help in the improvement of the underlying soil; but this has a knock on benefit of smoothing out the peaks and troughs of fast and slow growth to a more steady and slow growth pattern. I’ve made this my number 1, issue in achieving green surface consistency.
- Irrigation Management; understanding the water requirements and in particular soil water balance is an important aspect of green management. The finer grasses we seek to encourage can root more deeply than the weed annual meadow grass and as such our watering policy should be deeply, not daily.
- Localised Dry Patch Management; the scourge of many greens over the last 2 decades due, primarily to the overuse of sand top-dressings and the neglect of the soil/plant relationship. Localised Dry Patch is a condition (not a disease) that causes the soil to become hydrophobic (water repellent) and can cause major disruption to the surface levels. Localised Dry Patch is also a season long problem in most cases regardless of how much rain or irrigation there is; once it takes hold it is usually very difficult to overcome.
- Mowing Frequency; we looked at this issue in more depth last week. Mowing frequency is at least 100 times more relevant to green consistency than mowing height. Shaving the green down to 3mm is damaging to the grass plants and counterproductive in producing a performance green in the longer term. If we truly want a consistent green, we need to make some hard decisions on how we are going to manage the workload.
- Thatch Layer Control and Management; closely related to, and the catalyst for most other green maintenance problems, thatch is only a problem on intensively managed turf such as bowling greens. One of the most commonly discussed topic on this site.
- Compaction Control and Relief; one of the major catalysts for the build up of excessive thatch is the process of compaction of the soil. This causes the soil to become lacking aeration pore space and oxygen as a result.
- Sward Composition (grass types); a low priority on this list but none the less important in respect of the overall aim of the Performance Green Program. By doing the work required to encourage a tight sward of finer grasses we automatically do the things that encourage a healthy living soil and that is the key to a performance bowling green.
Where grass grows on soil of any type the health of the turf/soil eco-system can be assessed by looking at the thatch layer.
On grass areas where there is little or no human interference in the form of excessive compaction, fertiliser, pesticides and mechanical work (other than mowing) such as in meadows or parks the thatch layer will almost always be at the optimum level for a continued healthy turf/soil eco-system. This is due to the soil/plant relationship being in balance; a strong and sufficiently lively soil microbe population releases nutrition from the thatch layer as it decomposes naturally.
As we move to areas that are subjected to progressively higher maintenance and wear activity, the thatch layer is susceptible to becoming thicker and denser and therefore needs more intensive management if the turf/soil relationship is to be kept in balance.
This can be observed by taking samples from a variety of grassed areas and comparing them to your bowling green’s thatch layer; rough meadows and areas such as the roughs on golf courses being the most natural and healthy areas and greens usually being the least healthy and in need of the most remedial work to keep them right.
When turf is used for bowling or other activities, the soil becomes compacted which is literally the expulsion of air from the soil. This throws the natural balance in the turf/soil relationship and makes it necessary for us to intervene to correct things.It is important to remember that thatch is always being produced and the more vigorous and intensively used and managed the turf is the faster it produces thatch. The desireable fine bent grasses and the common weed-grass, annual meadowgrass are prolific thatch producers.
If we don’t do the right things to correct this effect or indeed if we don’t do them often enough the green can very quickly fall into the circle of decline we looked at in an earlier article.
After LDP there is probably more information on this site about Thatch than anything else.
Thatch production by grass plants is a natural process.
Thatch is the layer at the very top of the green surface between the green grass blades and the brown soil beneath.
Simply put; the bigger the distance between the green and the brown, the bigger a problem you have.
The denser and wetter and smellier the thatch layer between the green and the brown the more likely it is that you will be suffering other problems like fungal disease, slime, algae, moss, weeds, localised dry patch, bumpy surface, lack of green speed, lack of green consistency, grass growth problems, recovery problems, skinned heads, slippery surface and loss of grass cover.
Thatch is not an isolated problem; it usually comes along with some or all of the above.
To get a more thorough understanding of the processes going on here, have a look at this article.
For more detailed information on thatch, there are more articles here.
Performance Bowling Greens eBook is here.