Aeration is an essential practice of a good annual lawn treatment, it is the most effective way of reducing sub-surface thatch and compaction in lawns, often the main cause of moss.
Scarification is the mechanical removal of surface thatch from a lawn which naturally forms on a lawn.
However, when it gets too tick it prevents important nutrients such as water, fertiliser and oxygen from getting to the grass roots. The results is a mossy and spongy lawn.
Scarification removes most of the surface thatch and should be a feature of any good annual lawn maintenance program.