When there is excessive thatch the soil is not as able to insulate the turf crowns against temperature extremes. Thatch can reduce the effectiveness of pesticides. Thatch accumulates when the rate of shoot growth exceeds the rate at which the above ground parts of the plant decompose. Practices which promote excessive shoot growth increase thatch production. Soil pH - Thatch formation increases as soil pH decreases.
Acid soils reduce microbial activity and hence reduce the breakdown of thatch.
Liming acid soils will help reduce thatch build up. Fertilization and irrigation - Fertilization stimulates turfgrass growth. Excessive fertilization will force turf to grown more quickly than the microorganisms can break it down. Excessive irrigation will limit the oxygen in the soil which the microorganisms need to survive. It is important to provide enough fertilizer to keep turf healthy but not so much as to overstimulate it.