Top dressing is the application of a bulky material to the surface of the turf. Usually, this material is a mixture of good quality soil, sand and a source of humus. Ideally this material should be sterilised. The annual application of top dressing is a matter of routine for the professional greenkeeper, but is an unheard-of technique for nearly all home lawn lovers!
Benefits of top dressing
To make level any minor hollows on the lawn so that a true surface is obtained.
To produce a denser sward, the formation of new shoots is stimulated and the layer of top dressing promotes the development of runners.
The soil surface is gradually built up with a improved growing medium, thatch tends to decompose in this layer better and drought resistance is improved.
The water capacity in sandy soils can be improved by increasing the percentage of peat (humus) in the top dressing.
Drainage in heavy soils is improved by having a high percentage of sand in the top dressing, especially if hollow-tinning or spiking is carried out before.
Soil exchange can be achieved improving the growing medium by regular hollow-tinning and top dressing.
How to best apply the dressing
The best time to apply top dressing is Autumn - so early September to the end of October.
Firstly, cut the lawn at your normal height of cut.
Scarify the lawn first if thatch is present.
Aerate by spiking, slitting or hollow tinning (clear up cores that you remove and put on compost heap).
Apply top dressing at a rate of 1 - 3 kg per square meter. If the material is bagged, tip the top dressing into small heaps evenly over the lawn. If the material is in bulk/loose, shovel the material into small heaps.
Use a rake, lute, birch broom to level evenly over area. (A heavy ladder pulled along the surface acts as a lute, pulling the top dressing off the high areas and dropping it into the low areas).
Use a drag mat to help move top dressing to base of plant.
Under no circumstances should you smother the grass.
