Hydroponics is the centuries-old agricultural practice of
growing plants in a nutrient solution with or without an
inert medium providing plant support.
The hanging gardens of Babylon are assumed to be the
first large scale use of hydroponics. In 1600, a Belgian
discovered that plants did not need soil to grow and grew a
160 pound willow using only water.
Since then, many universities have used hydroponics to
isolate various chemical elements and they affect plant
Today, hydroponics is used throughout the world for
production of food. These operations range from families in
third world countries raising food to feed themselves to
large-scale commercial operations covering hundreds of
At present, there are approximately 30,000 acres of
commercial hydroponics operations world-wide, of which the
U.S. has about 800 acres. Most of the U.S. large-scale
operations are owned by Canadian and European corporations.
Only 200-300 acres are owned and operated by U.S. citizens.
Controlled Environment Hydroponic growing (growing in a
greenhouse) is prized around the world by countries lacking
enough fertile land, having short growing seasons, or
lacking water for irrigation.
Hydroponic systems can range from the raft system where
the plants' roots are totally submerged in a nurient
solution to a drip system timed to irrigate anything from
cactus to watercress.
This system consists of two containers. The lower
container has the nutrient solution, while the upper
container has the plant in a medium. Holes drilled in the
top container allow the nutrient solution to reach the
medium and plant roots.
Deep Pot System
A bucket lid with a growing pot built in is filled with
medium and placed on a bucket filled with nutrient solution.
Again, the nuatrient goes through the perforations in the
growing pot to feed the plant.
A Styrofoam raft drilled to hold plants is floated on the
nutrient solution. The plant roots grow down into the
Ebb & Flow (Fill and Drain) System
During World War II, the U.S. brought hydroponics to the
world with this updated method. A bed filled with
no-floatable medium is alternately filled with and drained
Containers or troughs are filled with a medium containing
plants. Plants are fed nutrient solution on a timed
Nutrient Film Technique (NFT)
This is a continuous 24-hour operating system where
plants are suspended with their roots being bathed in a thin
film of nutrient solution.
The plants are suspended in the air and their roots are
misted with nutrient solution on a timed sequence.
Nutrients are either manufactured or organic. Since
plants only absorb nutrients in their inorganic form, most
commercial hydroponic operations use manufactured nutrients
which are usually made by combining two or more naturally
Don't panic! Remember that water is actually a chemical
combination of two atoms of hydrogen and one atom of oxygen
The problem with organic hydroponics is that the organic
materials must be acted upon by microbes and turned into an
inorganic form that the plant can use. This not only takes
time but can be very complicated. However, a lot of thought
and effort is being put toward developing a consistantly
successful system. Currently people wishing to go organic
are using compost tea, worm castings, or aquaponics, where
fish are raised in tanks and their nutrient-enriched water
is run through a hydroponic system. The plants in the
hydroponic system use the nutrients out of the water,
essentially cleaning it, and the cleaned water is returned
to the fish. This makes it a small scale eco-system. While
this system does work, one has to remember that you are
trying to maintain and balance two different systems. In
other words, twice as much work and twice as many chances
for something to go wrong.
If a crop will grow in soil, it will grow in hydroponics
. . . as long as you come close to its normal growing
conditions in nature. Don't try to grow cactus in an
all-water system or try to grow tomatoes as you would
Commercially, crops are picked for their high return on
investment. For that reason, the major hydroponic crops are
tomatoes, cucumbers, peppers, herbs, leaf lettuce, and
flowers. In fact, the U.S. imports several hundred pounds of
these crops daily.
The Down Side
Here in the U.S., most commercial hydroponic operations
need some type of greenhouse structure to operate
year-round. These can be expensive. The heating and cooling
of greenhouses costs money and may draw down our energy
reserves. Due to these costs, only high-value crops are
* Using only 10% of the water used on field grown crops
results in great water savings.
* Herbicides are completely eliminated.
* The use of beneficial insects and natural pest control
all but eliminate pesticides.
* Fertilizer use is reduced and stays out of our water
table and streams.
* With greenhouses, marginal lands can be used, leaving
healthier, fertile lands for organic production. If one acre
of hydroponc greenhouse can produce 150 tons of tomatoes per
year, how much land does that free up?
* With plants being fed what they need when they need it,
one ends up with healthier, more nutritious food. Even in
organic production, there are certain minerals a plant will
be deficient in if the soil does not contain them.
Hydroponic nurient formulas are derived to make sure all the
micronutrients the plants need are included.
* A hydroponic greenhouse can be in almost continuous
production year-round, year after year. Other than a very
devastating natural disaster, production does not stop for
drought, too much rain, wind or freezing temperatures.
* A well-run hydroponic greenhouse can provide a farm
family with a more than adequate livelihood, allowing
parents to remain home if they so desire and giving their
children a chance to work hand-in-hand with their parents
while being able to put to use what they leaarn in school.
This would seem to be a great way to save the small-scale
Some photographs courtesy of
Oregon Dept of Agriculture.
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