Once May's UK daytime temperatures reach around 14° - 15° Celsius you know grass growth is going to be fairly vigorous, requiring you to mow your grass more frequently. Most clubs should be looking to mow their greens at least three times a week and, or depending on resources available, should consider mowing on an a daily basis.
All pre-season fertiliser applications will have 'kicked-in' with key playing surfaces becoming smoother and more consistent following Spring topdressing work.
For the next eight weeks or so, UK growth reaches a peak, therefore the emphasis will be on mowing frequency as long as there is sufficient moisture within the soil.
With daily mowing at around the summer norm of 4-5mm, there will be a need to supply the turf with a 'little and often' foliar feed, consisting of mainly Nitrogen, with other nutrients and ingredients, such as Potassium, added to the mix as required in order to meet the turf's needs.
As with most natural grass playing surfaces the performance of the green will be influenced by the inputs of the groundstaff.
Greens should be mown at least three times a week, with some grooming/verticutting or brushing being undertaken on a weekly/twice weekly cycle to improve air movement and reduce thatch levels building up in the sward profile.
Aeration should also continue, using a mix of micro, needle or star tines which give maximum effect and almost zero turf disturbance.
Regular use of a sarrel roller will be beneficial and the use of micro tines to aerate the green will help reduce soil compaction, 'vent' the root-zone and to allow water to move quickly from the surface and into the root-zone, thus encouraging the turf to root deeper.
May is also a good time to apply fertilisers, wetting agents and soil conditioners. See Pitchcare shop for a range of products.
Also be aware of other factors that may influence the performance of the green, many club greens are surrounded by hedges and trees which can cause shading problems. Reduced light levels, lower soil temperatures and restricted air movement will also affect grass growth.
Soil and air temperatures usually increase in May, often bringing on the need to irrigate. If soil profiles, particularly sandy soils, are allowed to dry out too much they often become water repellent (hydrophobic), a state when soils can become difficult to re-wet. Often the first areas to suffer on greens particularly crown greens are the high spots on the green. You may need to spend more time hand watering these problem areas.
However, the long term affect of drying greens could be detrimental to surface playability. The surface could begin to break up, particularly on sand predominant greens. Sand becomes unstable when in a dry state and the surface can become bumpy. Different grass species will respond differently under drought conditions, growth rates will vary depending on habit and root structure, thus promoting an uneven surface.
Once the soil goes beyond a certain drying stage you are likely to encounter dry patch symptoms, whereby the soil becomes hydrophobic, being unable to absorb water. The water simply runs off instead of soaking into the soil profile.
Water will also always wash off from the high spots into the low areas, so the low spots tend to remain green and lush. This variation of dry and wet areas will affect surface playability, the bowls will fly across the dry areas and slow down on the lush green areas.
Once soils become hydrophobic they can deny adequate water movement to other areas of the rootzone - often resulting in water deficit stress with symptoms that include a general decline in the biological health of the plant which in turn effects shoot and root growth.
You may need to consider using wetting agents to aid recovery or help prevent these problems occurring in the first place. Many greenkeepers now utilise wetting agents on a monthly basis to keep the rootzone in good condition.
The movement of nutrients in the soil is also dependant on the moisture state of the soil; dry rootzones will slow down or even prevent nutrients being assessable for the plant. Which, again, will result in plant health decline.
If you do not have adequate watering facilities it may be beneficial to raise the height of cut by 1mm to keep a bit more grass on the green during these dry periods. It may slow the game down a bit, but will help sustain your green through these difficult times.
It is important to water correctly; under or over watering will have a detrimental affect on plant health. You need only to apply enough water to replace what has been lost by evapotranspiration. Depending on the aspect of your green, soil type and herbage cover, you could be losing anything between 3-5mm of water per day. This will need to be replaced by watering .
It is important to ensure you water evenly and to depth, you want to ensure the water gets down beyond the rooting profile at least between 100-150mm. This will encourage deeper rooting as the green dries and the roots go in search of the descending water.
Also check your water quality, what pH is it? Is it suitable for your green? Check filters on recycled water systems. Poor water quality will affect plant growth and sustainability.
Most greenstaff will have already applied a spring/summer fertiliser, perhaps something like a 9:7:7 and will be looking to apply a summer fertiliser, reducing the N and P inputs to maintain a balanced growth during May. At the end of the month an application of a slow release fertiliser will see you through June and July.
Regular brushing and sweeping are important tasks to keep the surface clean, open and dry. A dry surface will aid resistance to disease. Keep an eye on fungal disease attack and use approved fungicides to treat infected areas.
The sward will be actively growing due to the increased soil temperatures, coupled with the stimulation of fertiliser applications. Regular mowing will be required to maintain sward height at around 4-5mm. Verticutting/grooming fortnightly can be carried out to help speed up the green and help improve the health of your turf.
With the development of mowing technology, most fine turf mowers have cassette fitting attachments that offer additional maintenance operations such as grooming and verticutting. These are both operations that effectively remove thatch and side shoot growth enabling the promotion of an upright plant and denser turf growth.
Some clubs now use turf irons (rollers) to prepare surfaces for play, these are specially designed ride on turf rollers that apply even pressure over the surface. However, rolling can have a detrimental affect on your turf if done at the wrong time or too often. There will be a need to increase the frequency of aeration techniques to counter balance the practice of rolling.
Seeding sparse or bare areas can be continued. Any rise in soil or air temperatures will help germination. Use germination sheets to aid this process but remove the sheets regularly to check for diseases. Remember that without good seed to soil contact the operation is useless. Ensure you use new seed as old material may not give you the required germination rates.
Irrigation equipment: Inspect installations for leaks. There may be a need to irrigate during any maintenance programmes. As air temperatures increase and daylight hours are getting longer, there is the likelihood of the soil and turf surface drying out. Longer growing days mean more evapotranspiration takes place, removing moisture from the soil.
Materials: Ensure you have organised and ordered the appropriate materials from suppliers, don't leave it too late! There should be a supply of topdressing and seed as well as your chosen fertiliser. Possibly some wetting agent and any chemical controls that could be needed at short notice.