Table of Contents
- Interactive Timeline
- Early History (Pre-history to 500 BCE)
- Beginnings of Botany (500 BCE to 1000 CE)
- Middle Ages (1000 CE to 1400 CE)
- The Renaissance (1400 CE to 1700 CE)
- Age of Enlightenment (1700 CE to 1800 CE)
- Victorian Era (1800 CE to 1900 CE)
- World Wars (1900 CE to 1950 CE)
- Contemporary (1950 CE to Now)
From early civilizations to the dawn of philosophy…
Use of plants for food purposes is known as agriculture. The advent of farming in human history signalled the start of civilization as we know it around 6000 BCE in what is referred to as the “Neolithic Revolution.” (1)
The use of medicinal plants and herbs us typically referred to as “herbalism.” As people began to learn more about plants, herbalism became part of botany and medicine.
Hydroponics is largely the result of combining the scientific knowledge gleaned from botany and herbalism with the practical methods employed in agriculture.
Chewing the bark of a willow tree provides effects similar to aspirin.
Artist’s impression of the Hanging Gardens
What’s interesting to know, however, is that the Hanging Gardens of Babylon may never have existed at all. It is the only one of the “Seven Ancient Wonders of the World” to have no definitive location, and the earliest writings about it were written over 300 years after it supposedly existed. (5) Later writings grew more exaggerated, with some describing the roof being nothing but the roots of trees.
Some archaeologists have posited an alternative explanation for the Hanging Gardens of Babylon; They were actually the Hanging Gardens at Nineveh. Assyria, which was a neighbor to Babylon, had a tradition of royally-constructed gardens. Stephanie Dalley, an archaeologist, has suggested that the actual Hanging Gardens were built by King Sennacherib of Assyria as a record of love for his wife. (6) The water for the gardens could have been brought in by aqueduct from nearby mountains. In addition, Sennacherib had developed a method of pumping water via an enclosed cork screw.
Beginnings of Botany
500 BCE to 1000 CE
Initial attempts at understanding plants and how to control them…
Theophrastus’ work was the biggest contribution to botanical knowledge for centuries, until the Middle Ages (7). His most famous works were Enquiry into Plants (also known as Historia Plantarum) and On the Causes of Plants.
His works are often divided into several books that make up the whole of his work. Enquiry into Plants is divided into three books, and is the most relevant to hydroponics.
- The first book attempted to categorize plants based on their properties. It also describes simple plant anatomy.
- The second book described plants changing into other species of plants if they are left alone. This is a typical error of Greek philosophers, who made assumptions about events occurring because they didn’t observe a change.
- The third book described all wild trees growing either from seeds or from roots. This was in direct opposition to the prevailing theory at the time, known as spontaneous generation. Spontaneous generation states that life can come from nothing.
- The last 6 books discuss specific plants and their properties and uses.
While his works exhibited the errors typical of Greek philosophers, Theophrastus brought attention to the importance of roots to a plant.
Man liked his cucumbers.
These proto-greenhouses were built with what is described as frames encased in “transparent stone” or cloths soaked in oil (to make them translucent). The transparent stone was written about by Pliny the Elder (9) in his Natural History, and described as lapis specularis, which is today known as selenite.
The cucumber-like vegetables were grown on special wagons filled with soil. On warm days, the wagons would be brought outside, and on cold days, they would be put inside.
1000 CE to 1400 CE
While the Middle Ages weren’t known for their advanced science, there were advancements…
While he was not the first European to visit China, he was the first to document his trip there and what he experienced.
In his writings, he describes “Chinese floating gardens,” but it is not entirely clear what this meant. It is likely this is a misunderstanding of Chinese farming methods or gardening techniques.
- Rice paddies and other farms were regularly flooded, and Marco Polo may not have known this, thus considering it a floating garden.
- Traditional Chinese gardens include water features close to the roots of plants. Marco Polo may have seen this as a floating garden.
Map of area near Tenochtitlan
Tenochtitlan was built in this strange location because the Aztecs were under attack from neighboring enemies and it was the safest place to construct a city.
Artist’s impression of Tenochtitlan
However, building in the center of several, shallow lakes presents a problem for farming food. Without sufficient farmland space, the Aztecs had to get creative.
The Aztec’s solution was to construct man-made islands in the shallow lakes. These man-made islands are called chinampas (Pronounced Chee-nam-pah). They were built by planting several stakes in the shallow water of the lakes, fencing off a small portion of the lake. Workers would then dump mud, sediment from the lake, dead organic matter, and more into the surrounded area. Eventually the staked area would rise above the lake surface and become usable farmland.
What chinampas looked like
Plants grown in chinampas showed incredible growth, owing to the rich material used for soil and constant hydration of the plants.
1400 CE to 1700 CE
Logic and reason take root…
These early active greenhouses featured a heating system built underneath the greenhouse itself in order to continue growing during the cold winter months.
An illustration of an Ondol, a traditional Korean form of underfloor heating.
Jean Baptist van Helmont
Philosophically, van Helmont believed that there were only 2 “primitive” elements:” Air and water. He believed that Earth was a derivation of water, and that fire was not an element.
One of van Helmont’s most important contributions to hydroponics, however, was the recognition that most of a plant’s weight comes from water. In a famous experiment, he planted a willow tree in a measured amount of soil for 5 years. He measured the amount of water he gave the tree, and at the end of 5 years he measured how much the tree weighed and how much the soil weighed. He found that the tree gained 164 lbs (74kg) while the soil weight only decreased by 2 ounces, virtually unchanged. He correctly deduced that a majority of the tree’s weight came from water.
A weeping willow tree.
Woodward had a very distinguished wig.
In his experiments, he found that plants grown with “impure” water grew better than plants grown with distilled water. He made distilled water “impure” by adding soil to it. From these experiments, he deduced that nutrients in the soil made water better for plants. (12)
Age of Enlightenment
1700 CE to 1800 CE
The scientific method is developed and employed, leading to great advances…
Priestly also explored other gases, with an unusual tendency to call them “airs” which he described in his work Experiments and Observations on Different Kinds of Air. (13) Part of the reasoning for calling gases airs, contrary to the prior discoveries of Jean Baptist van Helmont, was that he subscribed to a different theory called “Phlogiston theory.” The outdated theory proposed that a combustible “phlogiston” is contained within anything that is combustible, and released upon combustion.
In his works, he describes “airs” such as:
Here is Jan Ingenhousz, seen with his enormous schnoz.
In his famous experiment, he grew an underwater plant in a clear glass container. He noted that lots of gas bubbles came off of the plant not long after it was exposed to sunlight, and a few small bubbles of gas came off of the plant when it was kept in a dark area. He isolated the bubbles coming off in the light and identified them as oxygen gas. He also isolated the bubbles coming off of the plant in the dark and identified them as carbon dioxide.
An illustration of Igenhousz’s experiment.
This experiment showed that light is essential to the process of photosynthesis, and that plants produce oxygen in the presence of light.
- To quote from Senebier:
- “Since plants contain hydrogen whether they grow in sand, in sponge, or in powdered glass, it is evident that the plants do not obtain the hydrogen from these substances…light and water is indispensable to vegetation. Light does not contain inflammable air, while water does. Therefore it appears that one may believe that if some parts of plants relieve the water of its hydrogen, by combining with the latter, the oxygen must escape from the plant by the action of sunlight….” (15)
Now greenhouses could be built by the wealthy, becoming almost commonplace during the Victorian era.
1800 CE to 1900 CE
Peace, prosperity, and great wealth allow for further advancement…
Without this knowledge, growing plants hydroponically would be significantly more difficult. Growing hydroponically often requires more controlled conditions than growing outdoors in the soil.
The “N” of NPK was identified thanks to Jean-Baptiste Boussingault, and this would help later nutrient formulations such as the Hoagland solution.
Julius Von Sachs practicing his crazy eyes.
Of particular relevance to the field of hydroponics, he worked with another scientist named Wilhelm Knopp on nutrient solutions for for soilless gardens. In his book Plfanzenphysiologie, (Plant Physiology, 1892) he describes the concept of “water culture” and how nutrient solutions would be used for it.
1900 CE to 1950 CE
Necessity is the mother of invention…
Dr. Gericke’s book. If so inclined, it is available on Amazon.
Since Hoagland’s solution was created, it has been adapted to uniquely serve a variety of plants that are grown hydroponically.
Daniel would get his Ph.D from Hoagland, and would serve in WWII in the Pacific Theater. He was stationed on Ponape Island and later Wake Island, in regions with no arable soil (21). He grew food crops hydroponically in these regions using gravel and nutrient water. He would later go on to demonstrate how photosynthesis would generate ATP from ADP using the sun’s energy and a phosphorous group, also vital in the NPK macronutrients.
Purdue still researches hydroponics to a lesser extent today with their “Small Farms and Sustainable Agriculture” initiative.
1950 CE to Today
What now? Exploring recent developments since the 50s.
- Nutrient Film Technique (NFT)
- Hydroponic Food Production
- Walt Disney's EPCOT Center Opens
- NASA and the ESA
Nutrient Film technique relies on a constant flow of water and nutrient solution, and is therefore dependent on electricity, but it is also relatively simple to automate without computer controls. It is very sensitive to disruptions in water and nutrient flow, and plants downstream get fewer nutrients, but this technique also for much more active monitoring and control over the growing process, a trend we see today in indoor cannabis cultivation.
Not to mention, any plumbing work became significantly easier with the advent of Polyvinyl chloride, or PVC. This would enable hydroponic systems that weren’t ebb-and-flow or deep water culture to function with relative ease and low expense.
One thing to note is that the 1973 oil crisis set hydroponics back for a time precisely because it made plastics much more expensive, at least temporarily.
Of particular importance to NASA are hydroponic growing methods that don’t rely upon gravity. Rotating hydroponic setups, like the one featured in the image below, are one such innovation designed for use in space.
NASA has also been the primary driver behind aeroponic growing, and its derivation, fogponics. These methods of growing use microscopic water droplets to deliver water and nutrient solution to plant roots without requiring large amounts of liquid water. Space exploration is tight on weight limits, so any system that can reduce the amount of liquid water necessary is great. Aeroponics has an unusual side benefit as well — any plant grown aeroponically will not experience transplant shock when put into soil or a different medium.
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About the Author
Hunter Wilson is a community builder with Growers Network. He graduated from the University of Arizona in 2011 with a Masters in Teaching and in 2007 with a Bachelors in Biology.