ABSTRACT
During ancient times, people faced many challenges while gardening� Being the curious animal man is, he wanted to find out what made plants grow� Soil was a mysterious material that somehow provided the right conditions for plants to grow from seed into plants that produced edible parts� Often plagues and pestilence reduced or even destroyed the yields of plants that societies heavily depended on for their wellbeing� When crops failed, societies suffered famine and death� Such crop failures led to wars between neighboring communities and even the death of entire civilizations and cultures� I heard the phrase “No Agriculture, No Culture,” recently on a TV historical documentary� This statement clearly points out the fact that cultures and civilizations are dependent on crops for their survival� If man knew more of the causes of these crop failures, he could try to prevent them� This became the basis of agriculture-to find out the reasons for plants to thrive so that man could cultivate plants under favorable conditions, which would lead to abundant production�
Ancient civilizations became aware that water was essential for any agricultural practices, so populations gathered in areas that had an abundant source of water that could be used for growing plants� Usually, by streams, rivers, lakes, or springs that had fresh water, civilizations developed where they could practice agriculture� Fertile soil existed in valleys of rivers and near lakes� Such soil supported productive crops and human centers� When groups of inhabitants experienced harsh environments that restricted their agricultural crops, they needed to examine what factors reduced yields and what could be done to improve them�
In the early times, man became aware of growing plants in specific environments and tried new methods of cultivation both for ascetics and food� Egyptian hieroglyphic records of several hundred years BC describe growing plants in water� Theophrastus during 372-287 BC experimented with plant nutrition� A form of hydroponics was established with the hanging gardens of Babylon, the floating gardens of the Aztecs of Mexico, and the Chinese� However, these were not called “hydroponic” culture even though they were a form of it�
Further experiments with a scientific approach to discover plant constituents were carried out by numerous scientists during the 17th century and later� They were able to discover that water, soil, and air provided elements such as carbon, hydrogen, and oxygen that were constituents of plant matter� Researchers later continued to demonstrate that the minerals that plants contained came from the soil via the soil water�
This enabled scientists to later grow plants in water alone without soil provided that these minerals were added to the water�
This became “nutriculture,” where plant roots were immersed in a water solution containing salts of their essential elements�
From 1925 to 1935, laboratory-scale nutriculture was expanded to commercialscale production of crops� However, it was not until the 1930s and 1940s that the application of nutriculture was applied on a commercial scale by Dr� W� F� Gericke of the University of California and termed “hydroponics�” The word “hydroponics” was derived from two Greek words hydro (“water”) and ponos (“labor”)—“water working�”
In the 1940s, with the war in the Pacific, Gericke applied hydroponics to commercial production in the nonarable islands where troops were stationed� After the war, hydroponic culture was adopted by the greenhouse industry to resolve problems with soil-borne diseases and pests as well as structural and nutritional challenges faced by year-round growing in greenhouses (Figure 1�1)� Now, almost all crops grown in greenhouses, including vegetables and ornamentals, use some form of hydroponics� It may also be termed “soilless culture” when using an inert medium other than soil to which a nutrient solution is added�
Hydroponic greenhouse growing is now worldwide� Some of the largest vegetable greenhouse production regions include Holland, Spain, England, Canada, United States, Mexico, Turkey, China, Australia, and Middle Eastern countries� Holland has more than 25,000 acres of greenhouse production, which includes ornamentals and flowers� Canada has about 2800 acres of greenhouse hydroponic
vegetable production and the United States 1500 acres� China is rapidly expanding its greenhouse production with presently approximately 3100 acres� Other areas of expansion include Turkey, Mexico, Morocco, and Australia�
Hobby hydroponic culture started in the 1940s and 1950s with gravel and water culture systems� These were mainly “Do-It-Yourself” projects� In the 1970s, some of the first commercially available hobby hydroponic units entered the marketplace as automated systems to simplify hydroponics for households� The “City Green” hydroponicum was one of the first such units constructed of molded plastic with an upper growing tray and a nutrient reservoir below� The substrate was volcanic cinder rock or expanded clay irrigated by a small perforated plastic tube on the top of the medium� A tube from a fish aquarium pump outside was connected to the irrigation tube in the nutrient tank� The air pump tube was connected to the larger diameter irrigation tube� The space between the walls of the tubes at their connection permitted water to move up by the force of the air entering the irrigation tube as shown in Figure 1�2�
Presently, with the increased interest in home hydroponics, a vast number of designs and types of systems are marketed for all types of crops (Figures 1�3 and 1�4)� They are available online and/or in hydroponic outlets in most countries� Specific types of units and their application to most suitable crops is discussed later in Chapters 12, 13, and 15� In the future, with increased awareness of food quality and safety, I am sure the general population will adapt hydroponic growing in their households, especially for herbs and salad crops�
Commercial hydroponics in the future will become associated with tourist resorts and spas as they are emphasizing wellness programs for their guests� Industries with waste heat and geothermal sites will couple with hydroponic greenhouses to produce vegetables more economically by using cheaper sources of energy for heating� Increased efficient light sources, such as light emitting diode (LED) lights, are
rapidly entering the greenhouse industry in northerly latitudes where light is limited during winter months� This trend will continue with new sources of lighting�
Hydroponic greenhouse operations are now being established on roof tops of buildings in the centers of cosmopolitan cities (Figure 1�5)� Such operations now exist in Montreal, New York, and are presently expanding to Vancouver and New Jersey� Another approach is to locate greenhouses in parking lots adjacent to supermarkets�
These applications of hydroponics provide clients with fresh produce, free of toxic pesticides, and fully vine-ripened fruits such as tomatoes, peppers, and eggplants� The other factor is the saving of fossil fuels in long transportation for distant markets� The product is grown onsite at the retail outlet or with community-supported agriculture marketing where fresh vegetables are taken to nearby drop-off points for “subscribed” consumers to pick up� The concept is to have households sign up as a member and then pay a monthly fee for their vegetables that are in returnable baskets that are either picked up at the drop-off site or can be acquired at the greenhouse operation itself on specific days�
Going one step further into the future, I expect that high-rise vertical buildings will be constructed in city centers to grow vegetables� They could also be part of a condominium complex where some floors or a wing of the building would be modified to grow plants with highly efficient hydroponic systems, such as rotating, vertical structures� This technology of rotating, vertical hydroponic systems already exists� However, the success of these high-rise greenhouses is dependent on a very efficient source of supplementary lighting, so I believe that it could happen within a decade or so� Solar cells on the rooftop of the building or in a nearby parking space could provide the electrical needs for the lights�
Hydroponics opens up potential for growing crops under all environmental conditions including in your home and/or backyard� It is the wave of future growing for you, so be part of it!
