Localised Dry Patch typically rears its ugly head in June in the UK, but by then it is way too late to do anything about it. Once your green is displaying the large brown patches of desiccated grass and powder dry soil beneath, no amount of watering or wetting agent will bring it back fully this year. Now is the time to inspect your green and deal with it permanently.
Its time again for clubs to be thinking about the end of season maintenance program and many of these programs will follow “tradition” and will include the application of several tonnes of high sand content top-dressing.
However, one of the most prevalent problems on bowling greens in the UK is that of Localised Dry Patch LDP a condition that causes soil to become hydrophobic (water repellent) and which is undoubtedly related to excessive sand content in rootzone
The autumn renovation program is the only real chance clubs have to start to make inroads into the major problems with their greens and the only time when it is possible to make large corrections to thatch and compaction; and you’ve guessed it, thatch is another major problem associated with LDP.
Localised Dry Patch creates large dry areas on greens where grass dies back and the surface is disrupted. All attempts to re-wet these areas by watering the green are doomed to failure due to the water repellent nature of the underlying soil.
The application of yet more sandy top-dressing is not going to make this better; indeed it will in most cases make the problem worse next year.
It would be more beneficial to start the process of recovery by following a program that includes thatch reduction, wetting agent application and overseeding. All autumn programs should include the application of a granular fertiliser to correct any underlying deficiencies, usually a low N and high K product.
Where moss is a problem; and with LDP it usually is, you should use a proprietary moss-killer or lawn sand between 2 and 4 weeks before thatch removal work.
The recent hot and dry weather has seen the UK experience forest fires for the first time in a lot of years.
It’s a hot dry spring, just the thing to get the bowlers out and active early in the season.
But, of course with this comes a problem. How do you get a green that has just come through one of the most prolonged and cold winters on record to perform well when the underlying soil is powder dry?
Performance turf requires heat and moisture and it is inevitable that you will have to turn to your irrigation system at this time to keep your green’s progress moving forward. Failure to keep up now could result in a disastrous season later on when the green dries out unevenly, succumbs to Localised Dry patch or simply doesn’t perform due to a lack of moisture early in the season.
Over the last week or so we have been inundated with readers asking for advice on the correct irrigation of bowling greens.
There are 2 key pieces of information you need to know before you can hope to keep up with the irrigation requirements of your green:
- How much moisture (in mm) is being lost from the green each day due to evaporation from the soil and transpiration from the grass plants? The combined effect of this is, strangely enough called Evapo-transpiration or ET
- How much water (in mm) does your irrigation system apply for each minute of run time?
Armed with these two pieces of information you can water your green confidently without over or under doing it.
So what are the answers to these questions?
There is a detailed article on this here.
But you’ve come here for a cheat sheet haven’t you?
For a very large proportion of bowling greens the answers are as follows:
- Around 25mm per week.
- Approximately 0.5mm per minute of run time; i.e. 1mm requires 2 minutes of run time.
These answers are based on averages; so if you are suffering blisteringly dry heat the first answer could easily be higher. If you have anything other than a standard specification, 4 pop-up sprinkler system from one of the main manufacturers such as Toro, Hunter, Rainbird etc the second answer could be a lot different, particularly if you are using a hose.
Getting irrigation right is essential to achieving a consistently high performance bowling green.
For more detailed information on the problems associated with this issue have a look at these articles.
For more in depth information on calculating your irrigation requirements and inputs have a look here.
As always any questions or comments please feel free to contribute.
The watering of bowling greens is one of those critical issues in bowling that splits opinion across the game.
Some purists would see no artificial watering of greens regardless of how dry the weather gets. Some are in favour to different degrees; some would argue that the green should only be watered enough to keep it alive, while others demand that the green be watered heavily and often to keep it green.
For me the critical issue is as always performance.
We can argue about the right way to water or not water greens until the cows come home, but green performance is the only measure we should really be worrying about and that means we need to deal with individual greens on an individual basis.
Some greens, mainly those that haven’t been subjected to years of sandy top-dressings dry out evenly across the surface. As the weather gets drier, these greens get faster and smoother and everyone is happy. However, there is a point of no return for these greens also and a complete drought will see them go Read more
Recent summers have seen a lot of greens devastated by Localised Dry Patch a disorder that is rapidly becoming the scourge of Bowling Green Maintenance Specialists and Club Greenkeepers a like.
I make no apology for writing about this once again, because in my opinion this issue has the ability to accelerate the decline of many already shaky clubs.
It is also clear that there is a deep misunderstanding of the issue across the bowling community…how do I know this?
Well, on several occasions over the last week I have been confronted with some of the worst examples of Localised Dry Patch I have seen in 30 years; in some cases there is virtually no grass cover left and the green surfaces are unlikely to hold together until the end of the season, but…
Despite that, I am still coming up against two of the most mind boggling situations time after time:
- The first is when I am actually demonstrating Localised Dry Patch in action by removing soil samples from affected greens and showing committee members powder dry soil/sand; and they insist that they think the green needs a good top-dressing!
- The second is when I get a phone call or email from a club with the same severe LDP problems who have had a recommendation from an “expert” that they need to top-dress their green to over come the problem.
Listen folks; I know this is turning into a bit of a rant but here are a few bullet points that you must remember if your green and maybe even your club is going to survive:
- Localised Dry Patch (LDP) is a soil disorder not a disease so it can’t be reversed over-night by any quick fix method regardless of how convincing the salesman is!
- LDP has the capability to ruin your green beyond economical repair.
- LDP is so common because clubs have habitually thrown tonnes of sand based top-dressings at their greens for decades; the tipping point has been reached, many clubs are now trying to produce bowling surfaces with limited budgets on very high sand content soils; it can’t be done!
- More sand will only make the problems worse not better.
So what can be done?
Well currently if your green is affected even mildly by LDP and you are in the process of thinking about an autumn program that includes top-dressing with several tonnes of high sand content top-dressing you are not only damaging your green, but you are also wasting hundreds of pounds.
- My eBook Performance Bowling Greens, a practical guide costs less than a bag of fertiliser, so do your green a favour and just buy a copy…its peanuts compared to what you are about to do otherwise.
- In the book there is a clear plan for getting over LDP and moving your green to a consistently high performance surface.
- You will save a lot of cash by taking a more natural, less abusive approach to green maintenance.
- The savings you make could be what saves your club from going under and your green will be on the road to recovery and consistent high performance into the bargain.
If you decide to ignore this, then please take away one message “Stop Dressing”
The condition known as localised dry patch (LDP) which is so prevalent on bowling greens throughout the UK is a very frustrating problem for many bowling clubs.
The frustration comes mainly from the fact that LDP isn’t a disease so it can’t be eradicated by a simple application of fungicide or any other chemical.
LDP is instead a disorder of turf that causes the soil beneath some areas of the green to become hydrophobic or repellent to water.
LDP causes large areas of the green surface to turn brown and sometimes even recede below the main surface level, causing bumpy, uneven surfaces and an increasingly poor bowling experience as the season progresses.
Like almost everything else that goes wrong with bowling greens LDP is merely a symptom of other issues present on the green; in this case excessive sand content in the green’s rootzone profile (topsoil).
The excess of sand makes the rootzone inert and unable to retain moisture or nutrients. More importantly, the soil can’t sustain a big enough population of beneficial soil micro-organisms, which would assist with the decomposition of thatch and produce essential plant useable nutrients.
The recovery process can take several years, although there will be notable improvements to the green surface throughout the recovery process.
To overcome this problem, it is important to adopt a completely new approach to green maintenance along the lines of the performance greens program and the single most important part of this process is to stop throwing tonnes of sand at the green every year.
More information here: LDP
As bowling green maintenance specialists we get lots of questions every week about thatch. So here is a quick crash course on it; what it is, what it does and how to deal with it:
What is it?
Thatch is the name given to the mat of dead roots and shoots that accumulates on the surface of the green. Where moisture, nutrition and cultural practices are optimised for the desired grasses, thatch rarely becomes a problem. However, when soil air content is low, or if drainage is poor and the fertiliser program is not Read more
Air is a very important component of a Performance Bowling Green.
50% of a healthy, performance green will be air; 25% Micro-pores and 25% Macro-pores.
The Macro Pore or “aeration” space is where drainage happens.
The Micro-Pore or “capillary” space is where grass plant roots get their water and nutrients.
Tip the balance in favour of one or the other of these and things start to go wrong.
Compaction reduces the Macro air space in soil and inhibits drainage and root penetration. The soil now holds on to too much moisture and a whole raft of other problems ensue; particularly the build up of excessive thatch due to the anaerobic (lacking in oxygen) soil conditions brought about by the reduction in air space.
Thatch becomes a breeding ground for fungal disease and a base for Localised Dry Patch to take hold. The thatch doesn’t break down naturally as it should because there is a massive reduction in the population of aerobic soil microbes and they usually do this job.
Tip the balance the other way by applying excessive amounts of sand top-dressing and there is now too much air space, there is very little capillary space and the green starts to dry out too quickly. Localised Dry Patch now takes over, the surface is unpredictable and the soil can’t provide the nutrition the plants need naturally any more.
Yes, for a healthy living green that performs to order you need a lot of space; 50% air space.
Luckily, a healthy living soil knows how to do all of this without us.
We are only needed to help rectify the damage we inflict, which is mainly compaction and nutrient depletion through the removal of grass clippings.
Ahh! how simple!
My post from yesterday sparked a few questions by email about the term “Cool Season Grass”, a question only likely to crop up in the UK once every decade or so when we eventually get some hot summer weather! A brief summary of the differences between warm and cool season grasses below:
Cool Season Grasses
Cool Season turf grasses are best adapted to growing during the cool and moist periods of the year and do most of their growing in the UK during late spring/early summer. In a decent summer you will see growth rate tail off in mid summer and this will usually be followed by another growth spurt in late summer/early autumn. The cool season grasses are best adapted to grow well in temperatures ranging from 150 to 240 C. This group includes all of the usual turf forming suspects that are common in the UK such as Agrostis (Bent grasses), Poa (meadow grasses), Festuca (fescues) and Lolium (rye grasses).
Warm Season Grasses
The warm season turf grasses are best adapted to growth in the temperature range of 270 to 350 C, they grow best during the warmest part of the year and can go dormant and even suffer injury during cold weather. Dormancy typically kicks in at around 10 degrees when the entire turf will take on a yellow colour. Examples of the warm season grasses that some of our American, Australian and South African readers will be familiar with are Axonopus (Carpet grass), Cynodon (Bermuda grass), Paspalum (Bahia grass and Seashore paspallum) and Zoysia (Zoysia grass).
The main difference between the two groups is the way in which they photosynthesise or produce food for themselves. The first product of photosynthesis in cool season grasses is a 3 Carbon sugar molecule so these grasses are commonly referred to as C3 grasses. In warm season grasses the first product of photosynthesis is a 4 Carbon sugar molecule, so they are referred to as C4 grasses. C4 photosynthesis is thought to be an evolutionary adaptation that has allowed grasses to thrive in very warm and tropical environments.
However, there is a band of territories around the world where the annual climatic conditions are not suitable for one type of turfgrass all year round, especially if you want to produce a nice green turf. It is too hot in summer for cool season grasses to stay healthy and too cold in winter for the warm season grasses. This is called the transition zone and turf managers in these areas sometimes use over seeding methods to produce an actively growing, green stand of turf all year round. This typically means that they will over sow their warm season turf with rye grass seed in the autumn and the turf will transition from warm to cool season grass in the winter. When spring comes they will put undue stress on the cool season grass in order to make room for the recovering warm season species to take over again.
I was recently teaching golf industry professionals in Southern China, which is in this transition zone and the golf club where I was staying has gone to extreme lengths to make sure its customers are kept happy all year round. They have two greens at every hole, one with creeping bentgrass for the winter period and one with seashore paspallum for the summer period.
I will write a bit more on photosynthesis soon. Meantime if you have any questions just drop me a line as usual or leave a comment on this post.
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.