• Hydroponic plants have similar or higher amounts of nutrients than conventionally grown produce. • Hydroponic crops have greater yields and require fewer pesticides than traditional agricultural crops. • Hydroponic systems can hedge against climate change risks because they operate in climate-controlled conditions and are not exposed to temperature variations. • Hydroponic systems can be profitable despite high start-up costs. In The Gambia, hydroponic production costs are US$2.30 for 1 square meter (m2) of lettuce and US$3 for 1 m2 of sweet pepper, whereas profits reach US$6 for lettuce and US$15 for sweet pepper. • As hydroponic systems scale up, production costs decrease and profits come sooner. And processing hydroponic crops can improve their profitability. This chapter examines the potential of hydroponics as a frontier agricultural technology within a circular food economy. Hydroponics is the process of growing plants in nutrient solutions instead of soil (Verner et al. 2017; Jensen 1997). Hydroponics complements insect farming, which produces animal source foods in a circular food production model, by producing nutritious fruits, vegetables, and grains. Hydroponics is a climate-smart technology that can contribute to food security, job and livelihood creation, and environmental protection. The first section in the chapter defines hydroponics and its history, and the second section describes the various types of hydroponic systems. The third section describes the inputs needed to operate a hydroponic system, principally the water, nutrient solution, and growing medium. The fourth section looks at the outputs and products produced by hydroponic systems, including nutritious produce for human consumption and animal feed. The fifth section then examines the benefits from using hydroponics instead of traditional soil agriculture. These benefits include greater yields, high-value products, reduced land and water use, energy efficiency, pest management, and specific benefits for people in countries affected by fragility, conflict, and violence (FCV). The sixth section presents some of the limitations of hydroponic systems and how to mitigate them. These include capital requirements, running costs, and limited knowledge on the industry and its operations. ABOUT HYDROPONICS Hydroponics is an expanding practice in Africa that can grow crops quickly without soil. Growing hydroponic crops is not new; however, using hydroponics to achieve development goals, especially in harsh climates, is an innovative approach to development. Growing plants in nutrient-rich water has been practiced for centuries. Early examples of hydroponic growing include Babylon’s hanging gardens and the Aztecs’ floating gardens in Mexico. In 1929, a professor from the University of California, Berkeley began growing plants in a 194
Insect and Hydroponic Farming in Africa
