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.
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.
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:
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:
Limited plant growthConditions and plant types determined by the grower
Too high/ low temperatureTemperature controlled
Too much/ little sunLight controlled
Too much/ little rainControlled water supply
Bad weatherNo storms; no bad weather
Still more benefits of hydroponics are included in an environmental or nutritional category.
Soil loses its nutritional value; it is difficult to measure in terms of fertilityNutritional value of water is easily measured; plants are always nourished
Soil is home to many troublesome creaturesConditions are sterile, hygienic environment
Excess water is usedWater is conserved
Disease and pest problemsDisease and pests can be controlled
Pesticides contaminate plantsPesticide free
Some nutrients are wastedNutrient solution can be recycled
Soil can not be reusedGrowing mediums can be recycled
Much soil is necessaryLittle growing medium is necessary
Spacious amounts of arable land is usedNon-arable land can be used
Year round crop production uses fossil fuelsFossil fuels are not used
Not very pest resistantMore 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
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.
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.