Raviv, M., Agricultural Research Organization, Institute of Plant Sciences, Newe Ya'ar Research Center, P.O.B 1021, Ramat Yishay 30095, Israel
Lieth, J.H., Department of Plant Sciences, University of California, Mailstop 2, Davis CA 95616, United States

This chapter explains soilless culture and describes its significance in agriculture. It begins with a historical account of facets of soilless culture in agriculture, suggesting that substrates used throughout the world differ significantly as to their make-up, while attempting to adhere to a specific set of principles. These principles are quite complex, relating to physical and chemical factors of solids, liquids, and gasses in the root zone of the plant. Today the largest industries in which soilless production dominates are greenhouse production of ornamentals and vegetables and outdoor container nursery production. In urban horticulture, virtually all containerized plants are grown without any field soil. Following this, it deals with hydroponics, which simply means, growing plants without soil. Initially scientists used hydroponics mainly as a research tool to study particular aspects of plant nutrition and root function. Progress in plastics manufacturing, automation, production of completely soluble fertilizers, and especially the development of many types of substrates complemented the scientific achievements and brought soilless cultivation to a viable commercial stage. Today various types of soilless systems exist for growing vegetables and ornamentals in greenhouses. This has resulted in a wide variety of growing systems. Finally, it presents an account of the current prevailing trends with respect to soilless media in agriculture, all over the world. © 2008 Elsevier B.V. All rights reserved.