This document provides information about mulches and composting as part of an RHS certification course. It includes a quiz on previous lessons, describes different types of organic mulches like bark, leaf mould, and composted straw, outlining their benefits and limitations. It also outlines methods of composting like aerobic and anaerobic heap composting, leaf mould production, and using wormeries. The roles of bacteria, worms, and fungi in breaking down organic matter are described. Maintaining the right ratio of green to woody materials and including lime are important for effective composting.