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Hydroponics

Hydroponics is the centuries-old agricultural practice of growing plants in a nutrient solution with or without an inert medium providing plant support.

 

History

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 health.

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 acres.

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.

 

Systems

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.

Wick System

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.

Raft System

A Styrofoam raft drilled to hold plants is floated on the nutrient solution. The plant roots grow down into the solution.

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 of nutrient.

Drip System

Containers or troughs are filled with a medium containing plants. Plants are fed nutrient solution on a timed sequence.

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.

Aeroponics

The plants are suspended in the air and their roots are misted with nutrient solution on a timed sequence.

 

Nutrients

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 occuring elements.

Don't panic! Remember that water is actually a chemical combination of two atoms of hydrogen and one atom of oxygen - H2O.

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.

 

Crops

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 cactus.

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 grown commercially.

 

Hydroponic Advantages

* 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 family farm.

 

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green marble line

Some photographs courtesy of Oregon Dept of Agriculture.

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