Golf Greens Aeration

Aeration needs to be carried out throughout the year, with adapting the equipment and tines used to suit the ground conditions, time of year and other maintenance work being carried out.

The summer period is when greens and other areas of the course will look their best. This is also the time when golfers will expect minimal, if any, disturbance on the greens from maintenance activities. Grass is in a state of constant change as it progresses through its lifecycle. Leaves and basal sheaths die on a frequent and consistent basis and constant foot traffic and mechanical work compact the underlying soil, creating conditions which reduce the competitiveness of the grass sward.

Aeration is essential in maintaining surface layer openness to support the desirable soil to atmosphere air circulation which needs to take place. Without adequate aeration a build-up of anaerobic conditions can arise, which will be to the detriment of the grass plant but also to the playing quality of the green. A well aerated soil will provide adequate pore spaces within the soil allowing for improved drainage and root growth as well as contributing to the reduction and control of thatch. A green that is waterlogged for relatively long periods of time or holding excessive quantities of water due to poor aeration and drainage will create stagnant conditions leading to weak growth, reduced soil micro-biological activity and an unhealthy growing environment which makes the grass plant more susceptible to disease and damage from play. Grass roots need a good supply of fresh oxygen to grow well, and this is provided by having a well thought out aeration programme.

Nutrients are primarily taken up via roots, having been made available from the soil solution. A well-aerated profile allows roots to more easily explore to greater depths, increasing the volume of rootzone from which nutrients can be extracted and increasing the efficiency of uptake from fertilisers.

Aeration is arguably the second most important maintenance practice after mowing, yet like most activities, if it is not carried out under appropriate soil and ground conditions then the results are more detrimental than beneficial, reducing overall sward quality.

A spiked roller and micro-solid tines (pencil tines) are ideal aeration equipment during the drier summer months as they help keep the surface layer open, which aids the penetration of water to lower layers, with minimal surface disturbance.

Slit tine aeration, especially with longer tines, will typically be carried out more frequently during the autumn and early winter period, with the last slit tining sometimes taking place around the end of February to early March time as there is a concern that slits can open up during the drier periods of the year, when additional watering would be needed to keep them closed. Lighter weight and thinner, shallow slit or star-shaped tine equipment might also be considered during wet spring and late summer periods when solid tine aeration equipment might be too heavy to use yet where aeration work is still required to encourage surface water to infiltrate into the soil profile.

A well-aerated soil will enable irrigation and rainfall to infiltrate and percolate through the green profile that much quicker and with less resistance than would occur in a profile which has less air-pore spaces.

With a desire and increasing need to reduce the natural resource consumption on golf courses, the encouragement of a deeper-rooted sward will influence its ability to better able to withstand drought and prolonged dry periods yet still produce a satisfactory playing surface. A well-aerated sward will also be healthier and with less moisture retentive, with a more open profile that will reduce conditions that are more likely to encourage disease attack.

Thatch, especially spongy thatch which arises from annual meadow grass dominated swards, will also be discouraged by good aeration practices. Hollow-tine aeration would be carried out as part of a thatch removal programme and also as part of an overall renovation programme, especially during September, but also during March / April if deemed necessary.

The frequency of hollow-tining to address thatch and compaction issues would traditionally have been carried out “once every couple of years” (Sutton, M.A.F. (1950), ‘Golf Courses Design, Construction and Upkeep’, p.65) to “once every 3-years” (Escritt, J.R, (1978), ‘ABC of Turf Culture’, p.5), with overuse of hollow-tining resulting in a softer more easily worn surface and one which is more prone to weed and weed-grass invasion. Some conditions might actually require an annual to twice a year use of hollow-tining, but only where assessed as being necessary and to address a specific problem, but not to continue on this basis as part of routine renovation work. Where this is carried out then it would be done when weather conditions allow for rapid incorporation of any applied top-dressing and rapid seed germination to colonise bare exposed infilled holes.

The traditional frequency of once every 3-years (as a useful guide) does relate to the equivalent of 6 golf greens per year, with 18 greens being fully hollow-tined over a three-year period. This does make one wonder if this relationship had some influence over the suggested guide frequency? Autumn would be the prime time to carry out hollow-tining, which would have been carried out using hand hollow-tine forks, which was a laborious task, and would have included hand sweeping up of extracted cores and then hand application and incorporation of top-dressing. If the desire was to ensure that 6 greens were finished prior to Christmas, this would have needed 2 greens per month to have been completed with the available labour, alongside the rest of the golf course work, so realistically this would have been the most that could be achieved at the time. And so, the ‘once every 3-years’ came into being as the ‘rule of thumb’ for hollow-tining, or maybe not, but it does fit the circumstance of the times very well.

Prior to the application of a fertiliser, irrigation, pesticide, wetting agent, grass seed or top-dressing it is usually desirable to aerate a green to aid efficiency of material uptake, incorporation or germination for seeds.