This document discusses hydroponics, which is a method of growing plants without soil. It provides a brief history of hydroponics, describes the main types of hydroponic systems, and discusses the requirements for a hydroponic system including nutrients, lighting, and temperature control. It also outlines the advantages of hydroponics such as higher yields and faster growth compared to traditional soil-based agriculture and provides examples of plants that can be grown hydroponically. Finally, it describes how to create a simple hydroponic system at home using water bottles.