Water-based Agriculture Goes Back Centuries
Hydroponic cultivation -- the growing of plants without soil -- is a science as ancient as the fabled Hanging Gardens of Babylon and as modern as a future NASA mission to Mars. Over the centuries, the crude agricultural techniques of the Babylonians and Aztecs have been refined into space-age plastic systems in which plants literally defy gravity -- growing toward a centrally placed light source like planets revolving around the sun. One day, hydroponics may ultimately provide solutions for massive global problems such as feeding the developing world, combating deforestation, and growing herb in Space. Already this unique collaboration between lab geeks and pot freaks has altered the course of horticultural history, and transformed marijuana from an exotic import of sometimes dubious quality into a billion-dollar homegrown industry bursting at the seams.

The modern history of hydro begins in the 17th century, when Jean van Helmont’s flawed yet hugely significant “Willow Tree Experiment” proved that plants obtain substances from water. Horticultural scientists soon began a struggle aimed at separating roots from dirt and uncovering new ways to provide nutrients to crops grown in non-traditional environments. Minor advancements continued throughout the 18th and 19th centuries, culminating in the experiments of a pair of German scientists, Julius von Sachs and W. Knop, sometimes referred to as “The Fathers of Waterculture,” who discovered that nitrogen, phosphorus and potassium (NPK) comprise the three main building blocks of plant growth and developed a nutrient formula based on their findings.

In the 1920’s, Dennis Hoagland developed his namesake standard solution, the basis of which is still used in many modern nutrient mixes. Hoagland’s Solution was the first to take into account micronutrients such as magnesium, sulfur and iron that are essential for healthy growth, but only required in minute amounts. Hoagland’s work provided the essential formula needed to grow crops wherever sunlight and weather permitted, thus pushing the boundaries of farming well beyond what had traditionally been considered fertile land.

During World War II, American troops overseas grew vegetables hydroponicaly to ease the burden of transporting perishable food to barren islands in the Pacific Theater and the arid regions of the Middle East. Iwo Jima and Okinawa, rocky and barely inhabitable, were transformed from blood-drenched battlegrounds to nourishing gardens of life. Soldiers protecting vital oil fields in the Arabian Peninsula ate vegetables produced locally in the harshest of desert environments.

The military kept growing hydro long after WWII, as Lt. Col. Marcus E. Cooper, Quartermaster, 1st Cavalry Division reported during the Korean War, “While we were in Kumchon we began to receive our first shipments of fresh vegetables. These were airlifted from the hydroponic farms in Japan. We had a standing priority on fresh foods for the hospital, then for the front-line troops. These vegetables were a real morale-builder.”

The 1960s marked the invention of drip irrigation systems and the nutrient film technique (NFT). Drip systems deliver nutrient solution directly to the roots, drop by drop, and typically use grow rocks (expanded clay pellets) or rockwool -- a controversial medium derived from heating rock and spinning the melted fiber into a texture not unlike cotton candy. NFT utilizes a trough for roots through which a thin stream or “film” of nutrient and oxygen-rich water is pumped. The simplicity of these new systems caused many cannabis cultivators to take their first serious look at hydroponics.

Anecdotal evidence from the early 1970s suggests that Hawaiian pot growers were the first to recognize the benefits of soil-less farming, perhaps inspired by the porous lava rocks native to the islands. The volcanic airy texture of these Hawaiian rocks impressed growers so much that the heat-expanded clay pellets used in modern hydroponics seek to imitate lava rocks in both water retention and available oxygen for roots. Soon Californians took notice of these “herban legends” and hydroponic cannabis began to win converts in the marijuana mainstream.

A combination of factors including Nixon’s 1969 crackdown on the Mexican border, Carter’s paraquat spraying, and the advent of powerful HID (High Intensity Discharge) indoor grow lighting made hydroponic marijuana growing increasingly intriguing, attractive and possible. Soon, companies sprang up to service the needs of those growing with the increasingly more complicated hydro systems.

In the 70’s, the largest supplier of specialized chemical nutrients, General Hydroponics, was born in California. Their iconic pink, green, and brown three-part liquid plant food quickly became the standard for hydroponic growers and their meteoric success spawned many imitators. Speaking of meteoric success, NASA joined forces with GH and sent plants and nutrients to the International Space Station to study plant growth outside the earth’s atmosphere and how best to supply food and oxygen for future colonization missions in space. The labs of General Hydroponics continue to make improvements in all aspects of plant science.

By the 1980’s, new sources of knowledge on hydro arrived: At the Volcani Institute in Ein Gedi, Dr. Hillel Soffer, an Israeli scientist, developed the aero-hydroponic method, helping to transform the desert into an oasis of bounty. The Epcot Center at Disneyworld introduced Living With the Land, a futuristic ride through hydroponic “gardens of tomorrow”. And HIGH TIMES magazine began to detail simple hydroponic systems, introducing thousands to a whole new way to grow buds. Info traveled in a pre-internet black market of ideas: seeds, clones, and growing information were bartered at informal trading posts on Grateful Dead tour and assorted festivals. Hydroponics proved to be increasingly appealing to urban pot growers concerned with disposal of spent soil, and equally excited both “green thumbs” and those more technologically minded.

In the 90’s, hydro came of age, while those at the forefront continued to make advances in soil-free growing, including aeroponics and aquaponics. In aeroponics, a fine mist of nutrient solution is constantly sprayed onto roots for extremely vigorous growth. Aquaponics combines fish farming (aquaculture) and hydroponics by growing fish in a reservoir, which in turn feed the plants with their excretions. Advancements in environmental controller technology during the Clinton decade also made it much easier to manipulate indoor grow-room temperature, humidity and carbon dioxide levels -- taking hydroponics to a whole new level of efficiency.

Today, systems such as the Omega and Bonsai rotate 360 degrees around vertically placed lights, while others crowd together small, squat, popsicle-stick-sized pot plants together in a “sea of green” style. Another popular new hydroponic method, Deep Water Culture (DWC) uses individual containers for each plant with air pumps that saturate the roots with oxygen. Getting more oxygen in deeper water has a dramatic effect on taproot length and plant size.

The best testament to the influence of hydroponics is that the term “hydro” has become slang for great buds -- a generic way to refer to the highest quality marijuana (i.e. “Pass the ‘dro”). Meanwhile, hydroponic magazines such as Growing Edge and Maximum Yield eschew any connection to marijuana altogether, hoping instead to focus on the many other benefits of soil-less growing. The affiliation between cannabis and hydroponics, however, may prove hard to shake. Companies such as Advanced Nutrients, founded in Canada in 1996 under the name Canadian Soilless, blatantly advertise their plant foods and supplements as being formulated and tested specifically for cannabis.

Increasingly, consumers and growers have been clamoring for organic hydro alternatives, and nutrient companies have taken notice. Coco fiber, made from the husks of coconuts, can replace toxic rockwool as a growing medium. Aside from claims that organically grown pot tastes and smokes better, there are also concerns about the wanton disposal of chemical nutrients into the water supply. Unscrupulous growers pump these toxic salts down sinks and toilets aggravating an already escalating ecological problem brought about by massive factory farms and big-business agriculture. Organic hydroponics seeks to combine the technology of waterculture with the simplicity and environmental benefits of traditional dirt farming.

The future of soil-less agriculture will take into account these concerns to further refine nutrients and simplify techniques. The benefits of hydroponics are obvious; fewer pests, quicker and more vigorous growth and less heavy labor. As the systems become cheaper and easier to operate, many more people will turn to hydroponics for their basic needs. One thing is for certain, whether growing in outer space or in the smallest of spaces, hydro is a great way to grow.

Hydroponics Timeline

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.

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.

1275-1292 
Marco Polo writes of “floating gardens” he discovers in China.

1492
Reannaissance man Leonardo da Vinci discovers that plants absorb mineral nutrients but his findings remain unpublished in his notebooks.

1640’s
Belgian Jean Baptista van Helmont proves that plants obtain substances from water in his famous willow tree experiment.

1699
John Woodward, a fellow of the Royal Society of England, discovers that plants derive minerals from soil mixed into water solutions.

1792
English Scientist Joseph Priestly shows that plants absorb carbon dioxide and give off oxygen.

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.

1920
Dennis R. Hoagland develops the “Hoagland’s Solution” creating a nutrient formula that is still the basis of what is used today.

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”

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.

1952
Over 8,000,000 lbs. of fresh produce are grown for military demand according to the US Army’s special hydroponics branch.

1960-65 
The Nutrient Film Technique (Alan Cooper/UK) and drip irrigation systems (Cornell University) are invented.

1969
Nixon’s crackdown along the Mexican border (Operation Intercept) has the unintended effect of jump-starting a burgeoning American and Canadian industry for homegrown marijuana.

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.

1982
In the July issue of HIGH TIMES (#83) “Do it Yourself Hydroponics” presents the first do-it-yourself units for growing marijuana in water. Disneyworld’s EPCOT Center opens The Land pavilion with a ride through hydroponically grown “gardens of tomorrow.”

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.

1989 
On October 26, known to cultivators as “Black Thursday,” the DEA launches Operation Green Merchant, an all-out attack on growers and suppliers of hydroponic systems (much to the surprise of orchid fanciers who were also swept up in the raids). While the arrests and harassment drive the industry further underground, it unintentionally spawns further advancements in grow-room security and efficiency.

1995
In the May issue of HIGH TIMES (#237) “The Great Hydro vs. Bio Debate” features Arjan of the Greenhouse, Wernard from Positronics and Kyle Kushman discussing the merits and limitations between growing organically in soil or in water with chemical nutrients.

1996
In the Netherlands Canna introduces Canna Coco, a medium for roots made from coconut husk fibers, a renewable and organic alternative to rockwool.

1998
In the October issue of HIGH TIMES (#278) cultivation expert Jorge Cervantes unveils hydro-organic growing as an alternative to using chemical nutrient salts in “Hydro-Organic: The Natural Approach to Hydroponics.”

1999
In the August issue of HIGH TIMES (#288) Kushman writes the 1st Annual Hydro Report, beginning a tradition of highlighting the best hydro systems and related products.