We have had an exceptionally wet July with many parts of the country receiving in excess of 200mm of rainfall. In some cases, this is causing a few problems in terms of what can be done or achieved in respect of carrying out essential maintenance regimes.
Clubs that have high thatch content will be suffering with surface water problems; the layer of thatch will prevent the water getting into the soil profile efficiently and hold on to it, acting like a sponge. At the same time this spongy wet layer will slow down the speed of the bowl during play.
The more free draining greens will also be suffering from loss of nutrients. The constant deluge of water is flushing many nutrients out of the soil profile leaving the plant under nourished. This, in turn, leads to poor grass growth and loss of colour , which makes the grass plant more vunerable to a disease attack.
Many clubs are getting a bout of red thread disease that is easily cured with an application of feed or, in the more severe cases, a dose of approved fungicide.
I still see too many bowling greens that have been put under undue stress by the mere fact that the greenkeeper has, in most cases, been pressurised into cutting the green much too short (below 4 mm), and rolling more frequently to increase green speed.
These practices will, in the short term, give the members what they want, fast greens, however, there is often a cost to bear for doing this. It generally comes in the form of the green suffering in many ways, grass cover begins to thin out, bare areas develop which allow weeds and mosses to establish. Beneath the surface the constant rolling will have compacted the soil profile, reducing the air spaces. This leads to poorer root growth, less movement of water and resulting in flooded surfaces.
In fact, the most common cause of slow bowling greens is the presence of a layer of accumulated organic fibre, commonly known as thatch. This is found just below the surface and is caused by the accumulation of matted grass stems. This is easily detectable when you walk across the green and the surface feels soft.
Do not be afraid to cut a sample plug from the green and check to see the extent of the thatch layer. Problems start occurring when you have more than 15mm depth of thatch.
This thatch layer is the main cause of many problems associated with the performance of the green. It is essential you control the amount of thatch by means of verticutting, grooming and scarification.
Greens that have high levels of thatch will take longer to dry out due to the thatch acting like a sponge.
Recent heavy showers will have affected the performance of many bowling greens; once wet and saturated the speed of the bowl will be slowed and the playing surface prone to damage.
Grass growth has been poor this year due to a combination of factors - prolonged wet weather, low air and soil temperatures and the fact that much needed nutrients have been washed out of the soil profiles. Moss growth has been prolific with ideal growing conditions being prevalent. Therefore, there are many greens suffering from high contents of moss and thatch. It will be important to implement a regular programme of verticutting and scarifying to remove these two evils from your swards.
Many greens will be looking sickly and yellow due to the fact that they are in need of a feed. The heavy rain will have certainly washed out nutrients from your soil profiles. An application of balanced summer fertiliser will rectify any loss of nutrients.
The summer bowling green maintenance regime continues, with regular mowing, grooming, feeding, brushing and watering.
Aeration is a key activity to ensure that there is a good air/gas exchange going on in the soil profile. The use of a sarrel roller (depth 5mm) helps to keep the surface open without disturbing the playing surface. Deeper aeration should only be done with micro tines when moist conditions allow penetration.
Brushing/switching of the playing surface keeps the green clean and removes any dew or surface water. Keeping the surface dry will improve resistance to disease.
Fertiliser treatment and turf tonics can be continued in accordance with your annual programme. If you haven't got a fertiliser programme, have your soil tested; try an independent soil analysis company for an impartial set of results.
To help prevent constant wear in the same locations it is important to move markers and rinks on flat greens.
Mowing frequency will often be dependent on the resources available to the clubs. Ideally, most clubs will be mowing daily, or at least three times a week. Regular mowing will be required to maintain sward height at around 4-8mm. Some clubs will reduce their mowing heights further, perhaps down to 3mm to help speed up the greens for club competitions. Prolonged mowing at these heights will lead to plant stress.
The speed of greens can be affected by other factors - too much thatch is the main cause of slow greens, or the fact that the greens have not had enough topdressings to maintain levels. Many bowlers complain about slow, inconsistent greens, often resulting in many clubs trying to speed them up by shaving off more grass. In the short term this may increase speed but, in the long term, it will be very damaging to the green.
The best way to balance the health of the grass plant and to achieve good green speed is to promote and carry out effective cultural practices to maintain surface playability:
* Remove and control the rate of unwanted vegetative growth (thatch and side growth) by regular grooming and verticutting operations.
* Light applications of topdressing will restore and maintain surface levels, thus increasing green speed.
* Mowing in several directions to reduce nap layering will help increase green speed.
* Double cutting for matches will increase green speed.
* Controlling soil moisture will help influence green speed.
* Timing of fertiliser products can affect green speed.
* Rolling the greens will increase greens speed. However, over-rolling will lead to problems. There are a number of specially designed turf irons that have been specially developed for increasing green speed.
Remember, it is important to balance the health and condition of the green when considering surface playability