refugee camp (box 5.1) showed that hydroponics decreased water usage for kale by 82 percent, spinach by 92 percent, and cowpeas by 84 percent compared with conventional farming (WFP Kenya 2020). It also showed that hydroponics uses 1.4 to 6 times less space, has greater yields, and has shorter growing cycles than conventional farming (figure 5.5). Versatility Hydroponic farming is possible across diverse climates and agro-ecological zones, including arid areas and urban zones (Heredia 2014). This is because hydroponics can be applied indoors. Growing in greenhouses or other controlled environments separates the production area from the location’s natural ecosystem; therefore, the ecosystem has no impact on the growth of hydroponic plants. As such, hydroponic farming can be done anywhere. This separation of growing from the natural environment also eliminates any environmental harm that agriculture would cause to the natural ecosystem, such as deforestation, monoculture, or any other form of environmental degradation. Thus, hydroponic food production has a minimal impact on natural resources and the environment and can be implemented in cities or on degraded lands. Producing crops in urban areas minimizes the distance between the food producer and the urban consumer (Bellows, Brown, and Smit 2004). A closer proximity of producers to markets reduces labor, transportation, packaging, and refrigeration requirements, leading to potentially substantial decreases in the use of resources and energy. In the United States, these additional costs account for up to 79 percent of a crop’s retail price (Wohlgenant 2001). FIGURE 5.5 Hydroponic Space, Water Needs, and Yields for Producing Kale, Spinach, and Cowpeas Space
Water
Number of plants
Liters
Kale 16
60
49
Spinach 49
3,780
380
Saved 82%
21 days stopped producing
39 days 3kg
4,860
415
Saved 92%
51 days 200g
38 days 3kg
3,200
530
Saved 84%
40 days 200g
32 days 15kg
71
82
Cowpeas 113
Yield/growth Yield/ Harvest growth days yields
800
1.4–6 times Source: WFP Kenya 2020. Note: g = grams; kg = kilograms. Understanding Hydroponics
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