Bowling Green Aeration

Aeration can be carried out throughout the year and can be undertaken in any direction of play, however, there is a need to adapt the equipment and tines used to suit the ground conditions, other maintenance work and the time of year. For example, a spiked roller is ideal during the drier summer months as it helps keeps the surface layer open, which aids the penetration of water to lower layers, without causing any surface disturbance, as well as helps fertiliser be readily washed into the surface layer. Ground conditions are an important consideration because surface (soil smearing and sealing of a surface, especially if earthworm casts are present) and sub-surface (compaction and soil smearing) damage should always be minimised, so soil and surface moisture conditions need to be assessed beforehand.

Whilst the entire green will be aerated on a regular basis, additional and selective, localised, aeration will also often be carried out on a regular basis. Some key areas where additional aeration will probably be needed are at the ends of the green where bowlers gather, access and exit points to the green, locations of known short jack games, as well as green edges to aid irrigation of dry edges.

Slit tine aeration, to a suitable depth of 100-150mm will usually be carried out during the autumn and early winter period, possibly to February or into March if appropriate, with a typical frequency being fortnightly to monthly. If this is carried out much later then the slits can open up during dry weather, especially if the green has a poorly developed root system. This can also be a problem in areas with low water pressure or where dry or drought conditions prevail.

If water restrictions are imposed, then the playability of a bowling green can be seriously compromised. Root activity reduces from springtime so if one of the aims of slit tine aeration is to help with root pruning, regeneration and development then little additional benefit would be gained from the use of slit tine aeration after this time until root activity starts to become a lot more active in the autumn period.
Shallow slit tining (typically 38mm to 50mm depth, but some might be just 25mm depth) with fine blades might also be considered during the playing season to maintain good air exchange between the soil and atmosphere and also for surface drainage, especially to help with heavy periodic downpours. So long as the machine used is not too heavy then compaction will be minimal, even under moist conditions when slits can be particularly beneficial in helping to remove surface water. Caution still needs to be taken to reduce the likelihood of slits opening in periods of prolonged dry weather: this activity might be more suited to areas in the west and north, rather than the typically drier south and east.

Solid tine aeration will be for early in the year and during the early part of the playing season in particular. If the tines can penetrate the surface during the season without causing any surface disturbance then they might also be used, especially where the tines are relatively thin in diameter. Occasional solid tining might also be considered after the end of season renovation and over the winter period. Offset the direction of aeration each time, but only by a small angle (about 10 degrees or so); do not cross aerate at 90 degrees as the likelihood of the green being opened up into small aeration squares during drying winds or later on in the following year when dry weather occurs can increase considerably.
Hollow-tine aeration would be carried out as part of a thatch removal programme and during renovation time, especially during September.

Leaving hollow tine holes open during the autumn and winter might be considered where compaction is a particular problem, as this will help to reduce overall soil density. However, some top-dressing will most likely be needed because the gaps created will introduce minor unevenness at a micro-level if no top-dressing is applied plus the green will gradually sink as no material is replacing that which is removed.

Hollow tine aeration can also be carried out during early spring, although it would be important to ensure tine holes are filled with a suitable topdressing along with grass seed to encourage rapid recolonization of the sward, without holes being present when the bowling season opens. This would only mostly be suitable where conditions are dry for a suitable length of time and on the warmer side to help aid seed germination and establishment prior to the start of the playing season.