Thatch

Thatch is the material that forms just above the soil. It consists of living and dead plant material. Some thatch is good, it provides traction and works as an insulator between temperature and moisture extremes. However, without managing thatch it can build up to the point that it can be detrimental to the health of the turf. Too much thatch can harbor turf pathogens and insects, can hold onto a lot of moisture and can restrict oxygen, fertilizers and plant protectants to the root zone. It also causes scalping and can require increased mowing heights and water. Unfortunately, 25% percent of thatch consists of a compound called lignin which can't be broken down by micro-organisms so it's inevitable that over time it can build up to undesirable levels when ignored. It is critical that aeration, topdressing and/or vertical mowing be done to keep it managed to optimal levels.