The topsoil 70/30 Mix is 70% screened soil and 30% compost. The screened soil is a sandy loam topsoil screened to 1/4 in. minus. The compost is made from decomposed vegetation and equestrian shavings. The compost is fully cooked for a minimum of 90 days. This material is used for sod or seed preparation for depths between 6 inches and 18 inches.