About Hydroponics

• 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

soilless medium and coined the term “hydroponics.” In traditional farming, soil stores the various nutrients required for plant growth. When water saturates the soil, the water picks up these nutrients and is absorbed by the plant’s roots (Campbell and Reece 2002), moving to the plant’s shoots, leaves, and fruits. In hydroponics, the need for soil is removed by feeding nutrient-rich water directly to the plant. As this chapter shows, hydroponic farming is increasingly becoming an important crop production technology in FCV contexts, including refugee camps and arid host communities in East and West Africa. For example, hydroponic systems have produced animal feed in Chad and human food in Kenya, Sudan, and Zambia. In Zambia, the World Food Programme (WFP) provided smallholder farmers hydroponic greenhouses to increase their resilience to climate variability. Each greenhouse holds approximately 2,000 plants that produce 1,300 kilograms (kg) of vegetables per month. The global hydroponic market was estimated at US$8.1 billion in 2019 and projected to grow at an annual growth rate of 12.1 percent to reach US$16 billion by 2025 (MarketsandMarkets 2019).

Hydroponics can be a livelihood option for displaced populations and other vulnerable populations. Most refugees do not expect to be displaced for long, but in reality displacement lasts 10 years on average (Devictor and Do 2017). As a result, there is a need to complement short-term humanitarian assistance to displaced communities with longer-term development efforts. Displaced populations generally have an entrepreneurial spirit and motivation to work. Moreover, many displaced populations worked in agriculture before migrating and could apply these skills to their new communities but often lack access to local land, knowledge, and resources. Providing this access is where the development community can make a difference. Generally, investing in agriculture is an effective long-term strategy to create jobs, build livelihoods, and strengthen food security (Verner 2016). Meanwhile, investing in hydroponics can be particularly beneficial for displaced persons, who often relocate to areas that are less suitable for conventional agriculture, such as arid resettlement camps or densely populated urban spaces. Providing jobs, livelihoods, and greater food security for the displaced will also reduce the resource burden on host communities. In the refugee and host community context, hydroponics has several advantages over conventional farming methods, including year-round production, increased yields, faster growth rates, access to fresh vegetables, greater potential for self-sustainability, and important social and psychological benefits for displaced individuals (WFP Kenya 2020). Moreover, simple hydroponic systems can be constructed with locally available and recycled materials, such as jerrycans or other discarded receptacles (Verner et al. 2017). Box 5.1 describes how the WFP used hydroponics to achieve development goals in a Kenyan refugee camp.

The hydroponic market was worth US$9.5 billion in 2020, with private sector investment driving its 11.3 percent compound annual growth rate (Intrado 2021). Investments in the hydroponic farming industry have grown rapidly over the past half-decade. From 2016 to 2017, venture capital

BOX 5.1 Hydroponic Pilot Project in Kenya’s Kakuma Refugee Camp

In December 2018, the World Food Programme launched a pilot project for simplified hydroponic crop production in Kenya’s Kakuma refugee camp. The pilot’s immediate objective was to determine the viability of hydroponics as a sustainable production method for refugee and host communities located in dry, harsh climates that are not suitable for agriculture. The pilot’s medium- to long-term objective was to improve refugees’ livelihoods and income-generating opportunities. Nine different hydroponic systems, including horizontal and vertical systems, were tested at 38 sites at the household and community levels. By the time the pilot project closed in December 2019, it had completed seven harvest cycles with 74 percent of the units remaining active and productive throughout the project’s duration. In total, the pilot helped 1,500 beneficiaries produce hydroponically grown vegetables (WFP Kenya 2020). Nearly 50 percent of the beneficiaries were women and 43 percent were youth, including 100 youth affected by scurvy, which was caused by prolonged vitamin C deficiency.

The pilot showed that hydroponics uses less water, has higher crop yields, and has faster growth rates than conventional field agriculture. Hydroponics used between 82 and 92 percent less water than conventional farming for growing kale, spinach, and cowpeas. One circular garden and two hydro crates, which together require 4 square meters of land, produced 2,780 grams of spinach, compared with 188 grams of spinach produced on a conventional farm using the same amount of space. That is 15 times more produce from the hydroponic system than from conventional farming. Meanwhile, one hanging garden, which accommodates only 64 plants, produced 446 grams of spinach, whereas the conventionally farmed plot, which accommodates 89 plants, produced only 200 grams of spinach. For cowpeas, the hanging garden required more time than conventional farming to reach harvest, 44 days compared with 40 days. The pilot also showed that the production costs for hydroponic systems decrease and profits come sooner as production units are scaled up. These results are mentioned throughout this chapter.

funding for vertical farming increased from US$36 million to US$271 million, a 753 percent increase. Much of this funding was directed to large companies with strong tech initiatives, such as Plenty USA and others. Additionally, crowdfunding on Kickstarter and Indiegogo for a variety of indoor agricultural initiatives increased by 1,000 percent, from US$2.8 million to US$28 million (Clark 2018). In Dubai, the Abu Dhabi Investment Office invested in Aerofarms USA to build a hydroponic farm. Barclays UK invested in 80 Acres, another hydroponic farm. In 2019, a group of investors invested US$100 million in InFarm,1 an indoor agricultural supplier, to scale the company’s growth in Europe and the United States (Agritecture 2019). Overall, venture capital investments in the indoor agricultural industry, including hydroponics, reached a new high of US$565 million in 2020, which was a 50 percent increase from 2019 (iGrow 2020). The increasing success of the commercial hydroponic industry owes to the success of both system input companies and hydroponic crop producers. Leading system input companies include Signify Holdings