Outputs

in West Bank and Gaza. It shows that NFT uses less water and produces greater crop yields than the wicking bed technique, but both grow crops much more efficiently than soil methods. This is especially the case considering that hydroponics can support three to five growing seasons per year and shorten harvest cycles, depending on crop types. More sophisticated hydroponic variations, such as aquaponics and aeroponics, use even less water than simpler hydroponic systems (Pantanella et al. 2012). The benefits from hydroponic systems compared with rainfed agriculture are not as clear-cut because in rainfed agriculture, rainwater cannot be “wasted” or “saved”—it is merely part of the hydrological cycle.

Growing Medium

A good plant-growing medium should be friable, well drained, well aerated, and moderately fertile. Rockwool is the most widely used hydroponic growing medium, although there are several other popular options, such as sand, gravel, perlite, sawdust, peat moss, vermiculite, and coconut coir. The growing medium’s porosity, water holding capacity, water availability, buffering capacity, and cation exchange capacity govern its interaction with the nutrient solution. For example, these factors determine how available nutrients are to the plants, how quickly the nutrient solution passes through the growing medium, and how often irrigation or fertigation—which includes the injection of fertilizers, water amendments, and other water-soluble products into a hydroponic system—is required (Wootton-Beard 2019). Pure topsoil is not recommended as a growing medium for seedlings or transplants because of problems with weeds, disease, drainage, aeration, and inconsistent physical conditions. Specific vegetable seed varieties are needed for certain climates and to resist certain diseases. Other varieties are better adapted to industrial production processes. For example, Roma plum tomatoes grow well in hot climates and are less likely to be damaged during storing, packaging, and transportation.

OUTPUTS

Nutritious Produce

Hydroponic produce has similar amounts of nutrients as conventionally grown produce (Treftz and Omaye 2016). In conventional farming, plants obtain nutrients from the soil, whereas in hydroponics, plants obtain nutrients from a solution. Since plants generate their own vitamins by absorbing nutrients and converting sunlight into energy, there are no differences in vitamin levels among plants grown in soil or in nutrient solutions. However, the mineral content can vary in hydroponic crops depending on the type of nutrient solution used. The nutrient and phytochemical levels differ slightly for all plants, regardless of the growing method. Each crop’s nutritional profile depends on the crop’s variety, the season in which it is harvested, the length of time between harvest and consumption, and how the crop is handled and stored.