Moss is a very small green plant that contains chlorophyll but has no roots.It binds to the soil surface by hairs to form clumps that gradually kill the lawn. Any condition impairing lawn growth could favour moss growth such as: excessive irrigation, shade, soil compaction, very short mowing height, thick thatch, the lack of fertilizers and acid soil. Moss persists for years if the cause of his presence is not solved. In addition, moss increases its territory from year to year.