the growing of plants without soil, has developed from the findings
of experiments carried out to determine what substances make plants
grow and the composition of plants. Such work on plant constituents
dates back as early as the 1600s. However, plants were being grown
in a soilless culture far earlier than this. Hydroponics is at least
as ancient as the pyramids. A primitive form has been carried on in
Kashmir for centuries.
The process of hydroponics growing in our oceans goes back to about
the time the earth was created. Hydroponics growing preceded soil
growing. But as a farming tool, many believe it started in the ancient
city of Babylon with it's famous hanging gardens, which are listed
as one of the Seven Wonders of the Ancient World, and was probably
one of the first successful attempts to grow plants hydroponically.
floating gardens of the Aztecs of America, a nomadic tribe, they were
driven onto the marshy shore of Lake Tenochtitlan, located in the
great central valley of what is now Mexico. Roughly treated by their
more powerful neighbors, denied any arable land, the Aztecs survived
by exercising remarkable powers of invention. Since they had no land
on which to grow crops, they determined to manufacture it from the
materials at hand.
In what must have been a long process of trial and error, they learned
how to build rafts of rushes and reeds, lashing the stalks together
with tough roots. Then they dredged up soil from the shallow bottom
of the lake, piling it on the rafts. Because the soil came from the
lake bottom, it was rich in a variety of organic debris, decomposing
material that released large amounts of nutrients. These rafts, called
Chinampas, had abundant crops of vegetables, flowers, and even trees
planted on them. The roots of these plants, pushing down towards a
source of water, would grow though the floor of the raft and down
into the water.
These rafts, which never sank, were sometimes joined together to form
floating islands as much as two hundred feet long. Some Chinampas
even had a hut for a resident gardener. On market days, the gardener
might pole his raft close to a market place, picking and handing over
vegetables or flowers as shoppers purchased them.
By force of arms, the Aztecs defeated and conquered the peoples who
had once oppressed them. Despite their great size their empire finally
assumed, they never abandoned the site on the lake. Their once crude
village became a huge, magnificent city and the rafts, invented in
a gamble to stave off perverty, proliferated to keep pace with the
demands of the capital city of Central Mexico.
arriving to the New World in search of gold, the sight of these islands
astonished the conquering Spaniards. Indeed, the spectacle of an entire
grove of trees seemingly suspended on the water must have been perplexing,
even frightening in those 16th century days of the Spanish conquest.
William Prescott, the historian who chronicled the destruction of
the Aztec empire by the Spaniards, described the Chinampas as "Wondering
Islands of Verdure, teeming with flowers and vegetables and moving
like rafts over the water". Chinampas continued in use on the lake
well into the nineteenth century, though in greatly diminished numbers.
So, as you can see, hydroponics is not a new concept.
Many gardening writers have suggested that the Hanging Gardens of
Babylon were in fact an elaborate hydroponics system, into which fresh
water rich in oxygen and nutrients was regularly pumped.
The world's rice crops have been grown in this way from time immemorial.
And also the floating gardens of the Chinese, as described by Marco
Polo in his famous journal, are examples of "hydroponic culture".
Ancient Egyptian hieroglyphic records dating back to several hundred
years BC describe the growing of plants in water along the Nile without
Before the time of Aristotle, Theophrastus (327-287 BC) undertook
various experiments in crop nutrition. Botanical studies by Dioscorides
date back to the first century AD
The earliest recorded scientific approach to discover plant constituents
was in 1600 when Belgian Jan van Helmont showed in his classical experiment
that plants obtain substances from water. He planted a 5-pound willow
shoot in a tube containing 200 pounds of dried soil that was covered
to keep out dust. After 5 years of regular watering with rainwater
he found the willow shoot increased in weight by 160 pounds, while
the soil lost less than 2 ounces. His conclusion that plants obtain
substances for growth from water was correct. However, he failed to
realize that they also require carbon dioxide and oxygen from the
In 1699, John Woodward, a fellow of the Royal Society of England,
grew plants in water containing various types of soil, the first man-made
hydroponics nutrient solution, and found that the greatest growth
occurred in water which contained the most soil. Since they knew little
of chemistry in those days, he was not able to identify specific growing
elements. He thereby concluded that plant growth was a result of certain
substances and minerals in the water, derived from enriched soil,
rather than simply from water itself.
In the decades that followed Woodwards research. European plant physiologists
established many things. They proved that water is absorbed by plant
roots, that it passes through the plants stem system, and that it
escapes into the air through pores in the leaves. They showed that
plant roots take up minerals from either soil or water, and that leaves
draw carbon dioxide from the air. They demonstrated that plants roots
also take up oxygen.
Further progress in identifying these substances was slow until more
sophisticated research techniques were developed and advances were
The modern theory of chemistry, made great advances during the seventeenth
and eighteenth centuries, subsequently revolutionized scientific research.
Plants when analyzed, consisted only of elements derived from water,
soil and air.
The experiments of Sir Humphrey Davy, inventor of the Safety-Lamp,
had evolved a method of effecting chemical decomposition by means
of an electric current. Several of the elements which go to make up
matter were brought to light, and it was now possible for chemists
to split-up a compound into it's constituent parts.
In 1792 the brilliant English scientist Joseph Priestley discovered
that plants placed in a chamber having a high level of "Fixed Air"
(Carbon Dioxide) will gradually absorb the carbon dioxide and give
off oxygen. Jean Ingen-Housz, some two years later, carried Priestley's
work one step further, demonstrating that plants set in a chamber
filled with carbon dioxide could replace the gas with oxygen within
several hours if the chamber was placed in sunlight. Because sunlight
alone had no effect on a container of carbon dioxide, it was certain
that the plant was responsible for this remarkable transformation.
Ingen-Housz went on to establish that this process worked more quickly
in conditions of bright light, and that only the green parts of a
plant were involved.
In 1804, Nicolas De Saussure proposed and published, results of his
investigations that plants are composed of mineral and chemical elements
obtained from water, soil and air. By 1842 a list of nine elements
believed to be essential to plant growth had been made out. These
propositions were later verified by Jean Baptiste Boussingault (1851),
a French scientist who began as a mineralogist employed by a mining
company, turned to agricultural chemistry in the early 1850s.
In his experiments with inert growing media. By feeding plants with
water solutions of various combinations of soil elements growing in
pure sand, quartz and charcoal (an inert medium not soil), to which
were added solutions of known chemical composition. He concluded that
water was essential for plant growth in providing hydrogen and that
plant dry matter consisted of hydrogen plus carbon and oxygen which
came from the air. He also stated that plants contain nitrogen and
other mineral elements, and derive all of their nutrient requirements
from the soil elements he used, he was then able to identify the mineral
elements and what proportions were necessary to optimize plant growth,
which was a major breakthrough.
In 1856 Salm-Horsmar developed techniques using sand and other inert
media, various research workers had demonstrated by that time that
plants could be grown in an inert medium moistened with a water solution
containing minerals required by the plants. The next step was to eliminate
the medium entirely and grow the plants in a water solution containing
From discoveries and developments in the years 1859-1865 this technique
was accomplished by two German scientists, Julius von Sachs (1860),
professor of Botany at the University of Wurzburg (1832-1897), and
W. Knop (1861), an agricultural chemist. Knop has been called "The
Father of Water Culture".
In that same year (1860), Professor Julius von Sachs published the
first standard formula for a nutrient solution that could be dissolved
in water and in which plants could be successfully grown. This marked
the end of the long search for the source of the nutrients vital to
This was the origin of "Nutriculture" and similar techniques are still
used today in laboratory studies of plant physiology and plant nutrition.
These early investigations in plant nutrition demonstrated that normal
plant growth can be achieved by immersing the roots of a plant in
a water solution containing salts of nitrogen (N), phosphorus (P),
sulfur (S), potassium (K), calcium (Ca), and magnesium (Mg), which
are now defined as the macroelements or macronutrients (elements required
in relatively large amounts).
With further refinements in laboratory techniques and chemistry, scientists
discovered seven elements required by plants in relatively small quantities
- the microelements or trace elements. These include iron (Fe), chlorine
(Cl), manganese (Mn), boron (B), zinc (Zn), copper (Cu), and molybdenum
The addition of chemicals to water was found to produce a nutrient
solution which would support plant life, so that by 1920 the laboratory
preparation of water cultures had been standardized and the methods
for their use were well established.
In following years, researchers developed many diverse basic formulas
for the study of plant nutrition. Some of these workers were Tollens
(1882), Tottingham (1914), Shive (1915), Hoagland (1919), Deutschmann
(1932), Trelease (1933), Arnon (1938) and Robbins (1946). Many of
their formulas are still used in laboratory research on plant nutrition
and physiology today.
Interest in practical application of this "Nutriculture" did not develop
until about 1925 when the greenhouse industry expressed interest in
its use. Greenhouse soils had to be replaced frequently to overcome
problems of soil structure, fertility and pests. As a result, research
workers became aware of the potential use of Nutriculture to replace
conventional soil cultural methods.
Prior to 1930, most of the work done with soilless growing was oriented
to the laboratory for various plants experiments. Nutriculture, chemiculture,
and aquiculture were other terms, used during the 1920s and 1930s
to describe soilless culture. Between 1925 and 1935, extensive development
took place in modifying the laboratory techniques of Nutriculture
to large-scale crop production.
In the late 1920s and early 1930s, Dr. William F. Gericke of the University
of California extended his laboratory experiments and work on plant
nutrition to practical crops growing outside for large scale commercial
applications. In doing so he termed these Nutriculture systems "hydroponics".
The word was derived from two Greek words, hydro, meaning water and
ponos meaning labor - literally "water-working". His work is considered
the basis for all forms of hydroponic growing, even though it was
primarily limited to the water culture without the use of any rooting
Hydroponics is now defined as the science of growing plants without
the use of soil, but by use of an inert medium, such as gravel, sand,
peat, vermiculite, pubice or sawdust, to which is added a nutrient
solution containing all the essential elements needed by the plant
for its normal growth and development. Since many hydroponic methods
employ some type of medium that contains organic material like peat
or sawdust, it is often termed "soilless culture", while water culture
alone would be true hydroponics.
Today, hydroponics is the term used to describe the several ways in
which plants can be raised without soil. These methods, also known
generally as soilless gardening, include raising plants in containers
filled with water and any one of a number of non-soil mediums - including
gravel, sand, vermiculite and other more exotic mediums, such as crushed
rocks or bricks, shards of cinder blocks, and even styrofoam.
There are several excellent reasons for replacing soil with a sterile
medium. Soil-borne pests and diseases are immediately eliminated,
as are weeds. And the labor involved in tending your plants is markedly
More important, raising plants in a non-soil medium will allow you
to grow more plants in a limited amount of space. Food crops will
mature more rapidly and produce greater yields. Water and fertilizer
are conserved, since they can be reused. In addition, hydroponics
allows you to exert greater control over your plants, to unsure more
All of this is made possible by the relationship of a plant with its
growing medium. It isn't soil that plants need - it's the reserves
of nutrients and moisture contained in the soil, as well as the support
the soil renders the plant. Any growing medium will give adequate
support. And by raising plants in a sterile growing medium in which
there are no reserves of nutrients, you can be sure that every plant
gets the precise amount of water and nutrients it needs. Soil often
tends to leach water and nutrients away from plants, making the application
of correct amounts of fertilizer very difficult. In hydroponics, the
necessary nutrients are dissolved in water, and this rululting solution
is applied to the plants in exact doses at prescribed intervals.
Until 1936, raising plants in a water and nutrient solution was a
practice restricted to laboratories, where it was used to facilitate
the study of plant growth and root development.
Dr. Gericke grew vegetables hydroponically, including root crops,
such as beets, radishes, carrots, potatoes, and cereal crops, fruits,
ornamentals and flowers. Using water culture in large tanks in his
laboratory at the University of California, he succeeded in growing
tomatoes to heights of 25 feet.
Photographs of the professor standing on a step ladder to gather in
his crop appeared in newspapers throughout the country. Although spectacular,
his system was a little premature for commercial applications. It
was far too sensitive and required constant technical monitoring.
Many would-be hydroponic growers encountered problems with the Gericke
system because it required a great deal of technical knowledge and
ingenuity to build. Gericke's system consisted of a series of troughs
or basins over which he stretched a fine wire mesh. This in turn was
covered by a mulch of straw or other material. The plants were placed
on this mesh, with the roots extending downward into a water/nutrient
solution in the basin.
One of the main difficulties with this method was keeping a sufficient
supply of oxygen in the nutrient solution. The plants would exhaust
the oxygen rapidly, taking it up through the roots, and for this reason
it was imperative that a continuous supply of fresh oxygen be introduced
into the solution through some method of aeration. Another problem
was supporting the plants so that the growing tips of the roots were
held in the solution properly.
In 1936, W. F. Gericke and J. R. Travernetti of the University of
California published an account of the successful cultivation of tomatoes
in a water and nutrient solution. Since then a number of commercial
growers started experimenting with the techniques, and researchers
and agronomists at a number of agricultural colleges began working
to simplify and perfect the procedures. Numerous hydroponic units,
some on a very large scale, have been built in Mexico, Puerto Rico,
Hawaii, Israel, Japan, India, and Europe. In the United States, without
much public awareness, hydroponics has become big business, more than
500 hydroponic greenhouses have been started.
Dr. Gericke's application of hydroponics soon proved itself by providing
food for troops stationed on non-arable islands in the Pacific in
the early 1940s.
first triumph came when Pan American Airways decided to establish
a hydroponicum on the distant and barren Wake Island in the middle
of the Pacific Ocean in order to provide the passengers and crews
of the airlines with regular supplies of fresh vegetables. Then the
British Ministry of Agriculture began to take an active interest in
hydroponics, especially since its potential importance in the Grow-More-Food
Campaign during the 1939-1945 war was fully realized.
During the late 1940s, Robert B. and Alice P. Withrow, working at
Purdue University, developed a more practical hydroponic method. They
used inert gravel as a rooting medium. By alternately flooding and
draining the gravel in a container, plants were given maximum amounts
of both nutrient solution and air to the roots. This method later
became known as the gravel method of hydroponics, sometimes also termed
In wartime the shipping of fresh vegetables to overseas outposts was
not practical, and a coral island is not a place to grow them, hydroponics
solved the problem. During World War II, hydroponics, using the gravel
method, was given its first real test as a viable source for fresh
vegetables by the U. S. Armed Forces.
In 1945 the U. S. Air Force solved it's problem of providing it's
personnel with fresh vegetables by practicing hydroponics on a large
scale giving new impetus to the culture.
of the first of several large hydroponics farms was built on Ascension
Island in the South Atlantic. Ascention was used as a rest and fuel
stop by the United States Air Force, and the island was completely
barren. Since it was necessary to keep a large force there to service
planes, all food had to be flown or shipped in. There was a critical
need for fresh vegetables, and for this reason the first of many such
hydroponic installations established by our armed forces was built
there. The plants were grown in a gravel medium with the solution
pumped into the gravel on a preset cycle. The techniques developed
on Ascension were used in later installations on various islands in
the Pacific such as Iwo Jima and Okinawa.
On Wake Island, an atoll in the Pacific Ocean west of Hawaii, normally
incapable of producing crops, the rocky nature of the terrain ruled
out conventional farming. The U. S. Air Force constructed small hydroponic
growing beds there that provided only 120 square feet of growing area.
However, once the operation become productive, it's weekly yield consisted
of 30 pounds of tomatoes, 20 pounds of string beans, 40 pounds of
sweet corn and 20 heads of lettuce.
The U. S. Army also established hydroponic growing beds on the island
of Iwo Jima that employed crushed volcanic rock as the growing medium,
with comparable yields.
During this same period (1945), the Air Ministry in London took steps
to commence soilless culture at the desert base of Habbaniya in Iraq,
and at the arid island of Bahrein in the Persian Gulf, where important
oil fields are situated. In the case of the Habbaniya, a vital link
in Allied communications, all vegetables had had to be brought by
air from Palestine to feed the troops stationed there, and expensive
Both the American Army and the Royal Air Force opened hydroponic units
at military bases. Many millions of tons of vegetables produced without
soil were eaten by Allied Soldiers and Airmen during the war years.
After World War II the military command continued to use hydroponics.
For example, The United States Army has a special hydroponics branch,
which grew over 8,000,000 lbs. of fresh produce during 1952, a peak
year for military demand.
They also established on of the worlds largest hydroponic installations,
a 22 hectare project at Chofu, Japan. It became necessary to use hydroponics
in Japan because of the method of fertilization of the soil by the
It had been their practice for many years to use "Night Soil", containing
human excreta as a fertilizer. The soil was highly contaminated with
various types of bacteria and amoeba, and although the Japanese were
immune to these organisms, the occupying troops were not.
Covering 55 acres, it was designed to produce both seedlings and mature
vegetables for American occupation forces. It remained in operation
for over 15 years. The largest hydroponic installations up to that
time were built in Japan using the gravel culture method. Some of
the most successful installations have been those at isolated bases,
notably in Guyana, Iwo Jima and Ascention Island.
After World War II, a number of commercial installations were built
in the United States. The majority of these were located in Florida.
Most were out of doors and subject to the rigors of the weather. Poor
construction techniques and operating practices caused many of them
to be unsuccessful and production inconsistent. However, the commercial
use of hydroponics, grew and expanded throughout the world in the
1950s to such countries as Italy, Spain, France, England, Germany,
Sweden, the USSR and Israel.
One of the many problems encountered by the early hydroponics pioneers
was caused by the concrete used for the growing beds. Lime and other
elements leached into the nutrient solution. In addition, most metal
was also affected by the various elements in the solution. In many
of these early gardens, galvanized and iron pipe were used. Not only
did they corrode very quickly, but elements harmful or toxic to the
plants were released into the nutrient solution.
Nevertheless, interest in hydroponic culture continued for several
reasons. First, no soil was needed, and large plant population could
be grown in a very small area. Second, when fed properly, optimum
production could be attained. With most vegetables, growth was accelerated
and, as a rule, the quality was better than that of soil grown vegetables.
Produce grown hydroponically had much longer shelf life or keeping
Many of the oil and mining companies built large gardens at some of
their installations in different parts of the world where conventional
farming methods were not feasible. Some were in desert areas with
little or no rainfall or subsurface waters, and others were on islands,
such as those in the Caribbean, with little or no soil suitable for
Big commercial American headquarters in the Far East have over 80
acres devoted to vegetable units, to feed landless city dwellers,
while various oil companies in the West Indies, the Middle East, the
sandy wastes of the Arabian Peninsula and the Sahara Desert, operating
in barren areas, especially off the Venezuelan Coast at Aruba and
Curacao, and in Kuwait have found soilless methods invaluable for
ensuring that their employees get a regular ration of clean, health-giving
In the United States, extensive commercial hydroponics exist, producing
great quantities of food daily, especially in Illinois, Ohio, California,
Arizona, Indiana, Missouri and Florida, and there has been a noteworthy
development of soilless culture in Mexico and neighboring areas of
In addition to the large commercial systems built between 1945 and
the 1960s, much work was done on small units for apartments, homes,
and back yards, for growing both flowers and vegetables. Many of these
were not a complete success because of a number of factors: Poor rooting
media, the use of unsuitable materials, particularly in constructing
the troughs used as growing beds, and crude environmental control.
Even with the lack of success in many of these ventures, however,
hydroponic growers the world over were convinced that their problems
could be solved. There was also a growing conviction in the nimds
of many that the perfection of this method of growing food was absolutely
essential in light of declining food production and the worldwide
surveys have indicated that there are over 1,000,000 household soil-less
culture units operating in the United States for the production of
food alone. Russia, France, Canada, South Africa, Holland, Japan,
Australia and Germany are among other countries where hydroponics
is receiving the attention it deserves.
In addition to the work being done to develop hydroponics systems
for the production of vegetables, however, between 1930 and 1960 similar
work was being conducted to develop a system to produce livestock
and poultry feed. Researchers had found that cereal grains could be
grown very rapidly in this manner. Using grains such as barley, they
proved that 5 pounds of seed could be converted into 35 pounds of
lush green feed in 7 days. When used as a supplement to normal rations,
this green feed was extremely beneficial for all types of animals
and birds. In lactating animals, milk flow was increased. In the feed
lots, better conversion rates and gains were achieved at less cost
per pound of grain. In breeding stock the potency of males and conception
in females increased dramatically. Poultry also benefited in many
ways. Egg production increased while cannibalism, a constant problem
for poultrymen, ceased.
Here again, however, in developing a system that would produce consistently,
a number of problems arose. The early systems had little or no environmental
control, and with no control of temperature or humidity, there was
a constant fluctuation in the growth rate. Mold and fungi in the grasses
were an ever-present problem. The use of thoroughly clean seed grain
with a high germination ratio was found to be absolutley essential
if a good growth rate was to be achieved.
Nevertheless, in the face of these and other obstacles, a few dedicated
researchers continued to work to perfect a system that could produce
this nutritious feed continuously. With the development of new techniques,
equipment, and materials, units became available that were virtually
trouble free. Many of these are in use today on ranches, farms, and
in zoos all over the world.
Hydroponics did not reach India until 1946. In the summer of that
year the first research studies were commenced at the Government of
Bengal's Experimental Farm at Kalimpong in the Darjeeling District.
At the very beginning a number of problems peculiar to this sub-continent
had to be faced. Even a cursory study of the various methods which
were being practised in Britain and in America revealed how unsuited
they were for general adoption by the public of India. Various physiological
and practical reasons, in particular the elaborate expensive apparatus
required, were sufficient to prohibit them.
A novel system, of which practicability and simplicity must be the
keynotes would have to be introduced if hydroponics was to succeed
in Bengal, or in fact ever to prove of widespread value to the people
of this part of Asia. Careful appraisal of salient problems during
1946-1947 resulted in the development of the Bengal System of hydroponics,
which represented an effort to meet Indian requirements.
Among the well-known institutions which have contributed so much to
the establishment of the soilless cultivation of plants as a practical
proposition are, the Universities of Illinois, Ohio, Purdue and California
in the United States; The University of Reading, in Great Britain,
famous for it's pioneering work in new cropping techniques. Canada's
Central Experimental Farm at Ottawa, as well as the internationally
famous and important firm of Imperial Chemical Industries, Ltd., which
undertook the adaption of hydroponics to British conditions.
Other pioneers of hydroponics were the Boyce Thompson Institute for
Plant Research, New York; the New Jersey Agriculture Experiment Station;
the Alabama Polytechnic Institute; and the Horticultural Experiment
Station, Naaldwijk, Netherlands.
With the development of plastics, hydroponics took another large step
forward. If there is one single factor that could be credited with
making the hydroponics industry the success it is today, that factor
one of the most pressing problems encountered everywhere was the constant
leaching of detrimental elements into the solution from concrete,
rooting media, and other materials. With the advent of fiberglass
and such plastics as the different types of vinyl, polyethelene film,
and the many kinds of plastic pipe, this problem was virtually eliminated.
In the better producing systems being built in the world today plastics
are used throughout, and other than a few isolated bronze valves,
there is absolutely no metal. Even the pumps are epoxy coated. Using
these types of materials, along with an inert material as a rooting
medium, the grower is well on his way to success.
Plastics freed growers from the costly construction associated with
the concrete beds and tanks previously used. Beds are scraped out
of the underlying medium and simply lined with a heavy vinyl (20mil),
then filled with the growing medium. With the development of suitable
pumps, time clocks, plastic plumbing, solenoid valves and other equipment,
the entire hydroponic system can now be automated, or even computerized,
reducing both capital and operational costs.
A basic premise to keep in mind about hydroponics is its simplicity.
After the wheel was invented, I am sure many were confused and thought
it complicated. That was because they could not get their minds off
all the work the wheel replaced. This is the way it is with hydroponics.
Once you conquer the idea there must be more to it than this, and
forget about the work it eliminates, you too will agree: It is simple!
Another important breakthrough in hydroponics was the development
of a completely balanced plant food. Work in this area is still continuing,
but there are many ready made formulas available. Most of them are
good, but very few, if any, will work consistently without the use
of various addatives at different stages of the crop. There are also
many formulas available that can be mixed by anyone, but the average
grower is far better off using one fo the many commercial formulas.
In addition to the progress rate through the use of plastics and the
steady increase in production because of improved nutrient mixes,
another factor of tremendous importance to the future of the industry
was the development of better hardware for control of the environment
Initially, nearly all fo the early greenhouses were steam heated,
and the cost of this equipment virtually barred the small grower from
entering this field. With the development of forced-draft heaters
that used oil or gas, however, it became possible to build much smaller
units, and the advent of LP gas, such as butane and propane, made
possible the location of greenhouses in almost any area.
Constant improvements in these heating systems, particularly the introduction
of high-velocity fans and the convection tube method of circulating
warm air throughout a building, gave the grower better temperature
control in the greenhouse. For commercial operations in larger greenhouses,
however, a boiler system using steam or hot water remained the most
economical. It gave the grower wide latitude in the choice of fuels.
There has also been continuous improvements in techniques and equipment
for cooling any size greenhouse.
In addition to better environmental control, the use of new materials
such as polyethelene, poly-vinyl films, and translucent fiberglass
panels introduced completely new methods of low cost greenhouse contruction.
They give the builder a wide choice of material for covering any size
unit and also made possible many new shapes, sizes, and configurations.
Some of these materials will last only one season; others are guaranteed
for 20 years, against clouding, that causes light loss and against
shattering from hail; despite damage to the cover, there was little
or no damage to the crop. Had a light film or glass been used, however,
both the crop and cover would have been completely lost. The films
are good for temporary or semi-temporary cover. Many of these materials
also gave light diffusion that is beneficial to most plants.
As an example of the need for hydroponics, in 1950 there was a total
of 3.7 million acres of land under cultivation in the United States.
At that time the population in the United States was 150,718,000.
In 1970 the total acreage in cultivation had dropped to 3.2 million
and the population had grown to 204,000,000. In the next 20 years,
it is estimated that the population of the United States will grow
to 278,570,000, an increase of 79,000,000 people. It is hard to project
how many more acres will be lost to production during this time. Above
paragraph from United States Department of Agriculture and United
States Department of Commerce.
Hydroponics has become a reality for greenhouse growers in vertually
all climate areas. Large hydroponic installations exist throughout
the world for the growing of both flowers and vegetables. For example,
large hydroponic greenhouse complexes are now in operation in Tucson,
Arizona (11 acres); Phoenix, Arizona (about 15 acres); and Abu Dhabi
(over 25 acres), this installation uses desalted water from the Persian
Gulf. Tomatoes and cucumbers have proven to be the most successful
crops. Cabbages, radishes, and snap beans have also done very well.
There is ample space on almost any flat rooftop. All that is needed
in addition to this space is electricity, fuel and water. Systems
built in this manner will have the added advantage of being at, or
near, the marketplace, eliminating the need for long-distance transportation
of produce, such as we have today. Because the environment within
the hydroponic installations can be controlled, these systems can
produce vegetables year round in almost any climate.
The system designed and built in St. Louis proves there is no question
that we already have the technology to build such systems, inexpensively.
There will, however, be other systems, built by or for the homeowner
that will take up very little space. Some of these will be small enough
to be installed in the kitchen or other parts of the home. They will
produce an abundant supply of many types of food, particularly lettuce,
strawberries, and similar crops. There are already workable units
of this type available now.
Today, hydroponics is an established branch of agronomical science,
it helps feed millions of people; these units may be found flourishing
in the deserts of Israel, Lebanon and Kuwait, on the islands of Ceylon,
the Phillipines, on the rooftops of Calcutta and in the parched villages
of West Bengal.
In the Canary Islands, hundreds of acres of land are covered with
polyethylene supported by posts to form a single continuous structure
housing tomatoes grown hydroponically. The structure has open walls
so that the prevailing wind blows through to cool tha plants. The
structure helps to reduce transpirational loss of water from the plants
and to protect them from sudden rainstorms. Such structures can also
be used in such areas as the Caribbean and Hawaii.
Almost every state in the United States has a substantial hydroponic
greenhouse industry. Canada also uses hydroponics extensively in the
growing of greenhouse vegetable crops. About 90% of the greenhouse
industry in British Columbia, Canada, uses sawdust culture to overcome
soil structures and soil pest problems.
One-half of Vancouver Island's tomato crop and one-fifth of Moscow's
are hydroponically produced. There are full-fleged hydroponic systems
in American Nuclear Submarines, Russian Space Stations and on off-shore
drilling rigs. Large zoos keep their animals healthy with hydroponic
green food, and race horses stay sleek and powerful on grass grown
hydroponically year round.
There are large and small systems used by companies and individuals
as far north as Baffin Island and Eskimo Point in Canada's Arctic.
Commercial growers are using this marvelous technique to produce food
on a large scale from Israel to India, and from Armenia to the Sahara.
In arid regions of the world, such as Mexico and the Middle East,
where the supply of fresh water is limited, hydroponic complexes combined
with desalination units are being developed to use sea water as a
source of fresh water. The complexes are located near the ocean and
the plants are grown in the existing beach sand. In other areas of
the world, such as the Middle East, there is little land suitable
for farming. Because of the development of the oil industry and the
subsequent flow of wealth, the building of large hydroponic farms
to feed the exploding populations in these nations is inevitable.
If there is any one industry in the world today who's time has come,
it is hydroponics.
WHY GROW FOOD?
Food is something most Americans take for granted. Yet, according
to a recent poll "Gardens for All," by the Gallup Organization, 34
million households in America (that's over 43%) grow food, and the
number is increasing rapidly. Not since the old Victory Garden era
has there been more interest in gardening for food.
In the past several years, interests have changed. Fewer gardeners
are hobbyists. Many are interested in food costs, and more still are
concerned about taste and the nutritional values of the vegetables
they feed their families, the effects of chemicals, both to the environment
and health-wise. Also, there are growing numbers of people in the
United States who have a strong desire to become more self-sustaining.
Countries like the Canary Islands balance their economies by exporting
vast amounts of soilless-produced tomatoes, cucumbers and salad greens
to industrial states like Britain every year. From the Caribbean area,
too, Puerto Rican and Mexican growers ship immense quantities of luscious
hydroponic fruits and greenstuff to the insatiable United States and
Canadian markets. In England, Germany, France, the Netherlands and
Switzerland, flower firms often prefer to employ the soilless method
for commercial purposes, especially for the production of carnations
and other quality blooms. Roses and chrysanthemums are grown extensively
in Colorado and neighboring states for export. In 1971 nurseries in
those areas made gross profits of over 25 million dollars from hydroponically
raised flowers alone.
In the year 1975 alone, four different commercial Hawaiian growers
were producing tomatoes hydroponically and more installations were
planned. Stateside, more than five hundred commercial hydroponic greenhouses
were in operation in the United States.
Officially, soilless cultivation of plants is looked upon in Russia
as a biological industry coming between horticulture and manufacturing.
Other countries, not already mentioned, where hydroponics is in current
use include Australia, New Zealand, Spain, South Africa, Israel, particularly
in the Negev Desert and along the Dead Sea, Italy, the Scandinavian
lands, the Bahama Islands, Central Africa, East Africa, Kuwait, Brazil,
Poland, the Seychells, Singapore, Malaysia and Iran. This list is
not, of course, by any means exhaustive, but it does give some idea
of how widely spread soilless gardening is today.
Not many years ago, most of our fresh food and much of our processed
food was produced within a 100 mile radius of our homes. There were
hundreds of local farmers and food processors, each competing for
our business. With an abundance of food available, we could afford
to be choosy. If we did not like what we were offered, we could voice
a complaint or just buy from another source.
In those days "fresh" meant fresh. Local farmers were not as skilled
in the techniques of disguising poor quality. Since good fresh produce
was available at reasonable prices, we would not think of eating a
meal without several servings of fresh vegetables, not frozen or canned,
We see a much different picture today. Local farmers are almost extinct.
We now have larger and more centralized farms, larger food processors
and larger chemical companies supplying or farmers and food processors.
It is estimated, by the year 2000, one percent of our farms will control
over half our food supplies. Also, over 60 percent of farm profits
wil go to as few as 50 major companies.
We cannot ignore the worldwide food shortage any longer. We need more
food from fewer acres. But in order to get more from less, sacrifices
will ahve to be made. Among these sacrifices will be "fresh" food
which is not really fresh, less control over food quality, higher
food prices, and a much higher ration of processed food over fresh
With the demise of our local farmers, I believe we have already lost
out on fresh food and local control. Now in order to keep food costs
from getting out of control, it only stands to reason more food will
have to come to us processed.
It is estimated that 20 percent of all food produced in America (about
137 million tons, worth $31 billon) is wasted. Of that, about 60 million
tons, worth $5 billion is simply left in fields and orchards for lack
of commercial value. Add to that the increasingly high costs of packaging,
storing, preserving, handling, and transportation after it leaves
the field, and the result is clear. We as a nation must convert more
of our crop yields from fresh produce to processed foods.
True hydroponic culture is generally a means of growing plants in
a nutrient solution using no soil or other rooting medium, although
today almost all of the many different methods of growing plants without
soil employ various types of inert material for a rooting medium,
such as gravel, haydite, perlite, vermiculite, pumice, sand and others.
What is known as the Herbagere method hydroponic cultivation, invented
by a Belgian Botanist named Gaston Perin, is beginning to find widespread
use in the United States. this growing technique utilizes a number
of shallow rectangular trays containing grerminating seeds. The trays
are stacked one above the other in a sealed growing chamber. Each
of the tray bottoms contains narrow slits. This feature permits nutrient
solution introduced at the top tray to drip down through each tray
in the stack. This technique is sometimes referred to as vertical
farming. It has been applied to the growing of highly nutritious grass
for feeding of livestock and zoo animals.
The San Diego Zoo is one of a number of zoos that operate a hydroponic
growing chamber of this type. It's the size of a large house trailer.
Within the chamber a total of 252 white plastic trays are arranged
in several neat tiers.
Each day, 36 trays, one seventh of the total, are seeded with presoaked
barley. Nutrient solution is sprayed over the trays several times
each day to keep the seeds moist. The temperature in the chamber is
kept at from 64 to 68 degrees and the trays are bathed in flourescent
light continously, which serve to stimulate seed growth.
Since the growing cycle is seven days long, each day mature barley
is harvested from another set of thirty-six trays. The barley daily
harvest yields from five hundred to six hundred pounds of grass and
roots. Zoos in New York City (the Bronx Zoo), Chicago, Phoenix and
St. Louis operate the same kind of growing chambers. At the Bronx
Zoo, the grass is fed to most of the hoofed stock; the zebras, antelope,
deer and Mongolian wild horses.
Lettuce is another crop that lends itself to vertical farming. Lettuce
seedlings in small planting boxes are placed in trays which are stacked
one above the other in a metal rack. After their diet of liquid nutrients
for one month the plants reach maturity.
In the case of tomatoes, the dirt farmer raises about 3,500 plants
per acre. In hydroponics, the plants can be placed much closer together,
it's possible to cultivate as many as 10,000 plants on an acre of
In normal farming, crops have to be rotated, that is, grown in a fixed
order of succession. Otherwise, the nutrient level of the soil falls
below established minimums. Plainly speaking, the soil "Wears Out."
With soilless culture, there's never any need to rotate crops. The
farmer checks the solution and adds whatever nutrients may be needed.
Thus the nutrient level can be just as high at harvest time as it
was the day the crop was planted, and the same type of crop can be
grown in endless succession. If however, the grower decides he wants
to change to a different crop after the harvest, it's a simple matter
to do so. Another plus is growing does not have to be done on a seasonal
basis. Crops can be started so that a continuous supply of most any
vegetable or fruit can be obtained at any time of the year.
THE FUTURE Hydroponics is a very young science. It has been used on
a commercial basis for only 40 years. However, even in this relatively
short period of time, it has been adapted to many situations, from
outdoor field culture and indoor greenhouse culture to highly specialized
culture in atomic submarines to grow fresh vegetable for crews. It
is a space age science, but at the same time can be used in developing
countries of the Third World to provide intensive food production
in a limited area. It's only restraints are sources of fresh water
and nutrients. In areas where fresh water is not available, hydroponics
can use seawater through desalination. Therefore, it has potential
application in providing food in areas having vast regions of non-arable
land, such as deserts. Hydroponic complexes can be located along coastal
regions in combination with petroleium-fueled or atomic desalination
units, using the beach sand as the medium for growing the plants.
Another area in which hydroponics promises to play an important role
in the future is growing seedlings for reforestation, orchards, and
ornamental shrubbery. In a report published in 1966, researchers at
the University of Wisconsin stated that seedlings of white cedar,
blue and white spruce, red pine, and others were grown in a controlled
environment. Using a hydroponic system with controlled feedings of
a nutrient solution, the results of growth in one year were three
to four times as great as in year old nursery grown seedlings. The
extension of the growing season in this northern area, through the
use of hydroponics and more concentrated use of space, made it possible
to grow five to ten times a many plants in a given area. Some plantigs
of pine were 18 yeras old at the time this report was published and
were said to be growing vigorously. Report - American Nursery Man,
Hydroponics is a valuable means of growing fresh vegetables not only
in countries having little arable land and in those which are very
small in area yet have a large population. It could be particularly
useful in some smaller countries whose chief industry is tourism.
In such countries, tourist facilities, such as hotels, have often
taken over most arable areas of the country, forcing local agriculture
out of existence. Hydroponics could be used on the remaining non-arable
land to provide sufficient fresh vegetables for the indigenous population
as well as the tourists. Typical examples of such regions are the
West Indies and Hawaii, which have a large tourist industry and very
little farm land in vegetable production.
To illustrate the potential use of hydroponics, tomatoes grown in
this way could yield 150 tons per acre annually. A 10-acre site could
produce 3 million pounds annually. In Canada, the average per capita
consumption of tomatoes is 20 pounds. Thus, with a population of 20
million, the total annual consumption of tomatoes is 400 million poiunds
(200,000 tons). These tomatoes could be produced hydroponically on
1,300 acres of land!
But there continues to be problems that hamper the growth and development
of hydroponics as a whole. One problem is the negative attitude of
the directors and people of position in many of our colleges, universities
and government agencies, which has ranged from complete disinterest,
to open hostility. This attitude partly results from their own failure
to achieve crop yields matching those of many hydroponic growers.
Fortunately, in some of our schools, there are people who not only
have open minds, but who have also given generously of their time
and talents to help growers establish very successful hydroponic farms.
Another problem that has developed in the past few years is the ever-increasing
cost of energy for heating. In many areas the high cost of fuel has
caused a number of installations that were operating at a profit to
suddenly plunge deeply into the red, and some operators have been
forced to shut down entirely in the colder months. Since this is the
time of year when vegetables are at or near peak prices, these increased
fuel costs have had a disasterous effect on the industry as a whole,
including soil-based greenhousemen.
One bright spot in this picture is the development of solar heating
systems. Much research has and is being done in this field, and there
are many ready-built systems available on the market today. Also available
are a number of publications with detailed plans on hwo to build one's
own solar energy system. There will of course, be many new developments
in this field over the next few years, and solar energy may eventually
solve the delemma for all growers.
plans are being drawn for using the techniques of soilless culture
on space flights and even on the moon, or beyond. For hydroponics,
the future seems very bright.
The biggest danger to the growth and development of hydroponics has
been the influx of "instant experts" over the past 10 years. The success
of many growers using properly designed equipment has attracted these
self-styled authorities in ever-growing numbers. Making extravagant
claims, they have sold many shabby, poorly made copies of workable
units with the assurance that this was the easy road to riches. Many
of these fly-by-night promotions have been short lived, but, sadly,
others continue to flourish.
The cost to the would-be commercial grower for a properly designed
hydroponic system, housed in a manner that provides good environmental
control, can run into thousands of dollars. For this reason, he should
check very closely the qualifications of the seller. He should require
proof of claims regarding production and profit capability, back-up
service after the sale, research facilities and past records of the
If a person is willing to work and apply himself, plants can be grown
hydroponically by a complete novice with no past experience at growing
crops. The owner of a small 10x12 foot hydroponic greenhouse will
be able to produce all the fresh vegetables needed by a family of
four or five, provided he operates the unit on a year round basis.
Hydroponics can also be profitable on a commercial scale if the grower
devotes the time and attention required for any successful business.
The average yield of tomatoes per acre is eighteen times greater than
in conventional soil methods. Rarely do pesticides have to be used.