With over 60,000 copies sold since its first publication in 1986, this completely revised and updated 4th edition is the simplest and most informative guide to hydroponic gardening around. The book is incredibly detailed, and accessible to people of all ages and abilities, from the beginner to the most accomplished hydroponic gardener. It covers plants’ basic needs, their food and nutrient requirements, different hydroponic systems and growing mediums, germination and planting out, maintenance and pest and disease control – all subjects amply supported with illustrations, tables and photographs throughout.