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600 BC
Located in what is now Iraq, the Hanging Gardens of Babylon, one of the Seven Wonders of the World, are thought to be the first example of active soil-less growing.
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800 AD
Spirulina was used in the 9th century Kanem Empire, Africa. It is still in daily use today, dried into cakes called dihé, which are used to make broths for meals, and also sold in markets. The spirulina is harvested from small lakes and ponds around Lake Chad.
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1100 AD
Aztec Indians create floating gardens, known as chinampas, using layers of mud and vegetation to suspend crops over fresh water lakes in Central America.
Spirulina is believed to have been a food source for the Aztecs and other Mesoamericans until the 16th century; its harvesting from Lake Texcoco and subsequent sale as cakes is described by one of Cortés' soldiers. The Aztecs called it Tecuitlatl, meaning stone's excrement.
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1275-1292
Marco Polo writes of "floating gardens" he discovers in China.
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1492
Reannaissance man Leonardo da Vinci discovers that plants absorb mineral nutrients but his findings remain unpublished in his notebooks.
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1640's
Belgian Jean Baptista van Helmont proves that plants obtain substances from water in his famous willow tree experiment.
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1699
John Woodward, a fellow of the Royal Society of England, discovers that plants derive minerals from soil mixed into water solutions.
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1792
English Scientist Joseph Priestly shows that plants absorb carbon dioxide and give off oxygen.
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1856-1865
Two German scientists, Julius von Sachs and W. Knop, standardize a nutrient solution making it possible to grow in water only with no medium holding roots.
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1920
Dennis R. Hoagland develops the "Hoagland's Solution" creating a nutrient formula that is still the basis of what is used today.
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1920's and 30's
Dr. William F. Gericke at the University of California creates the term "hydroponics" to refer to growing plants in water without soil. The combination of the Greek words "hydro" for water and "ponos" for labor literally means "water-working"
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1940's
In the Pacific theater of World War II, US troops create their own food hydroponically on barren islands, including Iwo Jima and Okinawa. Hydroponics returns to Iraq as American forces stationed to protect oil fields in Habbaniya use large growing facilities for fresh vegetables. At Purdue, Robert and Alice Withrow alternately flood and drain plant roots held in gravel with nutrient solution creating what is now known as the Ebb and Flow system.
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1952
Over 8,000,000 lbs. of fresh produce are grown for military demand according to the US Army's special hydroponics branch.
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1960-65
The Nutrient Film Technique (Alan Cooper/UK) and drip irrigation systems (Cornell University) are invented.
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1970
Italian Dr. Franco Massantini pioneers the aeroponic method in which roots are suspended in a mist spray. Dutch researchers use rockwool slabs to secure plants in ebb & flow and drip systems.
Spirulina was found in abundance at Lake Texcoco by French researchers in the 1960s, but there is no reference to its use there as a daily food source after the 16th century. The first large-scale spirulina production plant, run by Sosa Texcoco, was established there in the early 1970s.
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1986-1988
Israeli Dr. Hillel Soffer, senior researcher at the VoIcani Institute at Ein Gedi, develops the aero-hydroponic method in which partially submerged roots are sprayed with an oxygen-rich nutrient solution.
