Ornamentals are plants that are grown for decorative purposes in gardens and landscape design projects, as houseplants, cut flowers and specimen display. They are grown in containers, in field plantings in nurseries and orchards. Compost additions to soil bring biological, chemical and physical benefits. The organic matter added in the compost adds to soil organic carbon and improves the water holding capacity of the soil. The chapter discusses the impacts of adding compost to containerized ornamental soil media, including improved physical characteristics in the volume-limited container, improved plant growth in container media with varying amounts of compost, macro and micronutrient content, the role of soluble salts and impacts from persistent herbicides. Also, the chapter discusses the role of compost in field-grown ornamentals, including the importance of compost stability, maturity, the impact of soluble salts, methods of application and disease suppressive benefits of compost addition.