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 hot heaps, anaerobic cool heaps, producing leaf mould, and using wormeries. The roles of bacteria, worms, and fungi in breaking down organic matter are defined. Learning objectives cover organic mulching materials, their properties, composting methods, and the roles of microorganisms and ratios in composting.