FREE ESSAY ON HYDROPONICS

HYDROPONICS

The word "hydroponics" is thought to have been derived from the Latin "water working."
Water is the basis for hydroponics. Stated plainly, hydroponics is the growth of plants
without soil.
History
Though often thought of as modern and experimental, hydroponics is an ancient practice.
Though it wasn't known at the time, the Hanging Gardens of Babylon were hydroponic. Less
famous, the Aztecs' Raft Gardens also were hydroponic. In the year 1699, scientist John
Woodward presented a paper before the Royal Society of England. His paper concerned an
experiment that he had performed involving plants grown in polluted river water versus
plants grown in rainwater. This paper attacked the problem of whether or not the health
of plants was determined by the dissolved solids of the water from which they were grown.
In the years 1851-1855, Jean Baptiste Boussingault, French chemist, performed an
experiment of plant growth in quartz and sand cultures with no soil. He used only water
and chemical nutrients. In Germany in 1860, botanist Julius von Sachs published the first
noted nutrient solution formula. In 1865, Wilhelm Knop, a German agricultural chemist,
formed another nutrient solution. In the years 1900-1920, scientists extended the
established number of elements that made a successful nutrient solution from six to ten.
Hydroponic experiments were becoming more successful with these new elements. In the
1920s William F. Gericke termed this method "hydroponics." Researchers began to realize
how this method of growth without soil could be useful. In the 1940s, mainly during World
War II, the United States armed forces executed hydroponic operations in the South
Pacific to cut down the cost of transportation of fresh fruits and vegetables to the
troops stationed on the islands. In the 1970s, Dr. Alan Cooper developed the system
called "Nutrient Film Technique" (defined on page 6). Today the use of hydroponics is
becoming more widespread.
The Hanging Gardens of Babylon were a series of solariums filled with plants.
Investigations have concluded that an intricate tunnel and pulley system was used to
bring the water from the ground to the top platform. It is a possibility that the water
used was waste from human inhabitants. This would actually make the gardens hydroponic
because nutrients were added to the plants.
The Aztec Floating Gardens or rafts were called "chinampas." They were locates on Lake
Tenochtitlan, in Mexico. The rafts were constructed of rushes and reeds that were bound
together with roots. The Aztecs then took mud from the bottom of the lake and collected
it on the top of the raft. Then vegetables, flowers, and even trees were grown on the
rafts. Some of the roots sprouted down into the lake. The nutrients in the mud and in the
lake helped to produce lush gardens.
Pros and Cons
Of recent years, the method of hydroponics has become more widely used to grow healthy
plants, vegetables, fruits, and herbs indoors. Plants can be grown out of soil, their
natural way of growth, because the physiological needs of plants can be met in an
environment void of soil. Nutrition in hydroponics is provided by a liquid solution made
of water and water soluble mineral elements. The plant's roots are supported in an "inert
medium." This inert medium will be discusses later in this report. Aside from the fact
that plants do not physiologically need soil, there are many other reasons why the use of
hydroponics is becoming more popular.
One of these reasons is that hydroponically grown vegetables claim dramatic increases in
vitamin and mineral content as opposed to geoponic (grown without the use of soil)
vegetables. 
There are also many advantages of hydroponics related to the caretaking and ease of
gardening. This is a chart to demonstrate some of these reasons:
Geoponic Growth Hydroponic Growth
Suitable soil must be found and present. Suitable soil is not necessary.
More time and space is necessary. Space requirements and growth time are reduced.
Plants must be planted; fields must be cultivated, etc. The heavy work is reduced.
The plot must be weeded. There are no weed problems.
Crops must be rotated (in commercial growth). There is no crop rotation.
Transplant shock can occur. Little if any transplant shock occurs.
Frequent watering of the plants is necessary. Plants do not need to be watered as often.
There are also benefits of indoor growth versus outdoor growth:
Outdoor Growth Indoor Growth
Limited plant growth Conditions and plant types determined by the grower
Too high/ low temperature Temperature controlled
Too much/ little sun Light controlled
Too much/ little rain Controlled water supply
Bad weather No storms; no bad weather
Still more benefits of hydroponics are included in an environmental or nutritional
category.
Geoponic Growth Hydroponic Growth
Soil loses its nutritional value; it is difficult to measure in terms of fertility
Nutritional value of water is easily measured; plants are always nourished
Soil is home to many troublesome creatures Conditions are sterile, hygienic environment 
Excess water is used Water is conserved
Disease and pest problems Disease and pests can be controlled
Pesticides contaminate plants Pesticide free
Some nutrients are wasted Nutrient solution can be recycled
Soil can not be reused Growing mediums can be recycled
Much soil is necessary Little growing medium is necessary
Spacious amounts of arable land is used Non-arable land can be used
Year round crop production uses fossil fuels Fossil fuels are not used
Not very pest resistant More pest resistant
Sometimes artificial ripening agents must be added to the produce Plants are always
vine-ripened
Hydroponics, in a small scale, has been used efficiently by farmers, on a commercial
level, for years. These hydroponic farmers have many advantages over farmers that farm
using soil. Some of these advantages have been summarized in the charts above. By using
hydroponics. A farmer is basically creating his own perfect nature. His time of growth,
yield of growth, and quality of products can be predicted and controlled while the
geoponic farmer has to deal with unforeseen events of nature. In addition, hydroponic
vegetables and fruits have been proven to be healthier than soil grown.
While the pros heavily outweigh the cons of hydroponics, there are some disadvantages.
Some of these are: 
 The cost of setting up a hydroponic system can be high. 
 In a commercial environment, knowledge and skill are needed to achieve maximum
production
 The benefits of helpful soil life is lacking
 The sharing of nutrient solutions can spread disease and pests
 There are some plant varieties that are not suitable for hydroponic growth
 While plants react quickly to good conditions, they react just as quickly to bad
conditions
Growing Techniques
The one main condition of hydroponics that must remain stable is the water supply. There
are many techniques of bringing water to the plants.
Nutrient Film Technique (NFT): This is the traditional form of water distribution. The
nutrients are supplied to the roots by growtubes. The remainder of the solution that is
not used is pulled back to a reservoir by way of gravity. 
Drip or Micro-Irrigation: This method has been used increasingly. A minimal amount of
water is used, with the plant receiving the full benefit. A submersed pump provides
nutrients to feed lines that constantly drip water over the plants and the roots. An
additional tube underneath receives the excess solution to be reused.
Aeroponics: The roots of the plants are hanging in an oxygen-rich nutrient solution. This
allows for easy inspection and pruning. Air pumps provide oxygen and other pumps spray
the roots with water.
Deep Water Culture: This is another form of aeroponics. The roots of a plant system are
submerged in water. A ventilator keeps the roots oxygenated.
Flood and Drain: These systems resemble NFT systems. A submersed pump connected to a
timer systematically floods a plastic growing bin. The inert medium and the roots are
drenched, and then drained by way of gravity. Rockwool (which will be discussed further
below) is the most common medium used with the Flood and Drain System.
Passive Planters/ Hydroculture: This is the most common method and will be used in the
project. These systems do not need a water or air pump, hence the name "passive."
Planters using this system use an uncontaminated, permeable medium. A nutrient store in
the base of the container used for growth allows the plants to take the exact amount of
water that they need. 
Inert Growth Mediums
In spite of the fact that hydroponically grown plants do not use soil, something must
still anchor them. There are many materials that can be used as these mediums. The type
of medium used depends on many factors, including the size and type of plants, and the
type of hydroponic system used. This section will discuss a few of the main mediums.
Heydite and Hydrocorn: Heydite is porous shale that allows for free drainage and air
space. Hydrocorn is clay pellets. Both are easy to reuse and clean and they are both good
for continuous drip systems. They provide secure foundation for large plants.
Rockwool: Rockwool is made by melting basalt rock and chalk into lava, then pulling it
into fibrous cubes. It insulates well and provides a good water/oxygen balance. Rockwool
is used in continuous drip or flood and drain systems. Most often Rockwool is only used
one time.
Perlite and Vermiculite: Perlite is a light white material that is often used in soil.
Vermiculite is a flaky shiny substance that is often mixed with Perlite They do not
provide enough support for large plants. They are often used when plants are young or
seedlings.
Some hydroponic systems do not require any medium at all and use some other means of
support.