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Encyclopedia > Hydroponics
Plants grown in a hydroponics grow box made to look like a computer
NASA researcher checking hydroponic onions with Bibb lettuce to his left and radishes to the right
NASA researcher checking hydroponic onions with Bibb lettuce to his left and radishes to the right
Example of autotrophic metabolism

Hydroponics is a method of growing plants using mineral nutrient solutions instead of soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel or mineral wool. A variety of techniques exist. Image File history File links Metadata No higher resolution available. ... Image File history File links Metadata No higher resolution available. ... Image File history File links Hydroponic_onions_nasa. ... Image File history File links Hydroponic_onions_nasa. ... Image File history File links Download high-resolution version (670x882, 125 KB) Used with permission from http://www. ... Image File history File links Download high-resolution version (670x882, 125 KB) Used with permission from http://www. ... For other uses, see Plant (disambiguation). ... A nutrient is a substance used in an organisms metabolism which must be taken in from the environment. ... Loess field in Germany Surface-water-gley developed in glacial till, Northern Ireland For the American hard rock band, see SOiL. For the System of a Down song, see Soil (song). ... For other uses, see Root (disambiguation). ... Expanded Perlite Perlite is an amorphous volcanic glass that has a relatively high water content. ... Gravel (largest fragment in this photo is about 4 cm) Gravel is rock that is of a certain particle size range. ... Mineral wool, means fibres made from minerals or metal oxides, be they synthetic or natural. ...

Plant physiology researchers discovered in the 19th century that plants absorb essential mineral nutrients as inorganic ions in water. In natural conditions, soil acts as a mineral nutrient reservoir but the soil itself is not essential to plant growth. When the mineral nutrients in the soil dissolve in water, plant roots are able to absorb them. When the required mineral nutrients are introduced into a plant's water supply artificially, soil is no longer required for the plant to thrive. Almost any terrestrial plant will grow with hydroponics, but some will do better than others. It is also very easy to do; the activity is often undertaken by very young children with such plants as watercress. Hydroponics is also a standard technique in biology research and teaching and a popular hobby. A germination rate experiment Plant physiology is a subdiscipline of botany concerned with the function, or physiology, of plants. ... ... Species Nasturtium nasturtium-aquaticum L. Nasturtium microphyllum Boenn ex Rchb. ...



Many people use the term hydroponics to describe any methods of growing that does not use soil (although some scientists dispute this definition) and in that sense ancient peoples such as the Babylonians and Aztecs used hydroponics, as nutrients were obtained from other sources. The mineral nutrient solutions used today for hydroponics were not developed until the 1800s.

The earliest published work on growing terrestrial plants without soil was the 1627 book, Sylva Sylvarum by Sir Francis Bacon, although he died in 1626. Water culture became a popular research technique after that. In 1699, John Woodward published his water culture experiments with spearmint. He found that plants in less-pure water sources grew better than plants in distilled water. Mineral nutrient solutions for soilless culture of plants were first perfected in the 1860s by the German botanists, Julius von Sachs and Wilhelm Knop. Growth of terrestrial plants without soil in mineral nutrient solutions was called solution culture. It quickly became a standard research and teaching technique and is still widely used today. Solution culture is now considered a type of hydroponics where there is no inert medium. For other persons named Francis Bacon, see Francis Bacon (disambiguation). ... John Woodward (May 1, 1665 - April 25, 1728) was an English naturalist and geologist. ... Binomial name Mentha spicata Crantz Spearmint (Mentha spicata, syn ) is a species of mint native to central and southern Europe, where it grows in wet soils. ... Julius von Sachs Julius von Sachs (October 2, 1832 - May 29, 1897), German botanist, was born in Breslau, Silesia. ...

In 1929, Professor William Frederick Gericke of the University of California at Berkeley began publicly promoting that solution culture be used for agricultural crop production. He first termed it aquaculture but later found that aquaculture was already applied to culture of aquatic organisms. Gericke created a sensation by growing tomato and other plants to a remarkable size in his backyard in mineral nutrient solutions rather than soil. By analogy with the ancient Greek term for agriculture, geoponics, the science of cultivating the earth, Gericke introduced the term hydroponics in 1937 (although he asserts that the term was suggested by Dr. W. A. Setchell, of the University of California) for the culture of plants in water (from the Greek hydros, water, and ponos, labor). Workers harvest catfish from the Delta Pride Catfish farms in Mississippi Aquaculture is the cultivation of aquatic organisms. ... For other uses, see Tomato (disambiguation). ...

Reports of Gericke's work and his claims that hydroponics would revolutionize plant agriculture prompted a huge number of requests for further information. Gericke refused to reveal his secrets claiming he had done the work at home on his own time. This refusal eventually resulted in his leaving the University of California. In 1940, he wrote the book, Complete Guide to Soilless Gardening.

Two other plant nutritionists at the University of California were asked to research Gericke's claims. Dennis R. Hoagland and Daniel I. Arnon wrote a classic 1938 agricultural bulletin, The Water Culture Method for Growing Plants Without Soil, debunking the exaggerated claims made about hydroponics. Hoagland and Arnon found that hydroponic crop yields were no better than crop yields with good quality soils. Crop yields were ultimately limited by factors other than mineral nutrients, especially light. This research, however, overlooked the fact that hydroponics has other advantages including the fact that the roots of the plant have constant access to oxygen and that the plants have access to as much or as little water as they need. This is important as one of the most common errors when growing is over- and under- watering; and hydroponics prevents this from occurring as large amounts of water can be made available to the plant and any water not used, drained away, recirculated, or actively aerated, eliminating anoxic conditions which drown root systems in soil. In soil, a grower needs to be very experienced to know exactly how much water to feed the plant. Too much and the plant will not be able to access oxygen; too little and the plant will lose the ability to transport nutrients, which are typically moved into the roots while in solution.

These two researchers developed several formulas for mineral nutrient solutions, known as Hoagland solutions. Modified Hoagland solutions are still used today.

One of the early successes of hydroponics occurred on Wake Island, a rocky atoll in the Pacific Ocean used as a refueling stop for Pan American Airlines. Hydroponics was used there in the 1930s to grow vegetables for the passengers. Hydroponics was a necessity on Wake Island because there was no soil, and it was prohibitively expensive to airlift in fresh vegetables. Pan American World Airways (Pan Am) was the United States principal international airline from the 1930s until its collapse in 1991, and was credited with many innovations that shaped the international airline industry. ...

In the 1960s, Allen Cooper of England developed the Nutrient Film Technique. The Land Pavilion at Walt Disney World's EPCOT Center opened in 1982 and prominently features a variety of hydroponic techniques. In recent decades, NASA has done extensive hydroponic research for their Controlled Ecological Life Support System or CELSS. Hydroponics intended to take place on Mars are using LED lighting to grow in different color spectrums with much less heat. The Land Pavillion is an attraction at the Epcot theme park which is part of Walt Disney World in Orlando, Florida. ... For other uses, see NASA (disambiguation). ... Controlled (or Closed) Ecological Life Support Systems or (acronym CELSS) are a type of scientific endeavor to create a self-supporting life support system for space stations and colonies typically through controlled ecological environments, such as the BioHome, BIOS-3, Biosphere 2 and Mars Base Zero. ...


Soilless culture

Gericke originally defined hydroponics as crop growth in mineral nutrient solutions, with no solid medium for the roots. He objected in print to people who applied the term hydroponics to other types of soilless culture such as sand culture and gravel culture. The distinction between hydroponics and soilless culture of plants has often been blurred. Soilless culture is a broader term than hydroponics; it only requires that no soils with clay or silt are used. Note that sand is a type of soil yet sand culture is considered a type of soilless culture. Hydroponics is always soilless culture, but not all soilless culture is hydroponics. Many types of soilless culture do not use the mineral nutrient solutions required for hydroponics. For other uses, see Sand (disambiguation). ...

Billions of container plants are produced annually, including fruit, shade and ornamental trees, shrubs, forest seedlings, vegetable seedlings, bedding plants, herbaceous perennials and vines. Most container plants are produced in soilless media, representing soilless culture. However, most are not hydroponics because the soilless medium often provides some of the mineral nutrients via slow release fertilizers, cation exchange and decomposition of the organic medium itself. Most soilless media for container plants also contain organic materials such as peat or composted bark, which provide some nitrogen to the plant. Greenhouse growth of plants in peat bags is often termed hydroponics, but technically it is not because the medium provides some of the mineral nutrients. Peat has a high cation exchange capacity and must be amended with limestone to raise the pH. Fertilizers are chemicals given to plants with the intention of promoting growth; they are usually applied either via the soil or by foliar spraying. ... Peat in Lewis, Scotland Peat is an accumulation of partially decayed vegetation matter. ... This article does not cite its references or sources. ... For other uses, see Limestone (disambiguation). ...


The two main types of hydroponics are solution culture and medium culture. Solution culture does not use a solid medium for the roots, just the nutrient solution. The three main types of solution culture are static solution culture, continuous flow solution culture and aeroponics. The medium culture method has a solid medium for the roots and is named for the type of medium, e.g. sand culture, gravel culture or rockwool culture. There are two main variations for each medium, subirrigation and top irrigation. For all techniques, most hydroponic reservoirs are now built of plastic but other materials have been used including concrete, glass, metal, vegetable solids and wood. The containers should exclude light to prevent algae growth in the nutrient solution. Irrigation is the artificial application of water to the soil usually for assisting in growing crops. ...

Static solution culture

In static solution culture, plants are grown in containers of nutrient solution, such as glass Mason jars (typically in-home applications), plastic buckets, tubs or tanks. The solution is usually gently aerated but may be unaerated. If unaerated, the solution level is kept low enough that enough roots are above the solution so they get adequate oxygen. A hole is cut in the lid of the reservoir for each plant. There can be one to many plants per reservoir. Reservoir size can be increased as plant size increases. A homemade system can be constructed from plastic food containers or glass canning jars with aeration provided by an aquarium pump, aquarium airline tubing and aquarium valves. Clear containers are covered with aluminum foil, butcher paper, black plastic or other material to exclude light, thus helping to eliminate the formation of algae. The nutrient solution is either changed on a schedule, such as once per week, or when the concentration drops below a certain level as determined with an electrical conductivity meter. Whenever the solution is depleted below a certain level, either water or fresh nutrient solution is added. A Mariotte's bottle can be used to automatically maintain the solution level. In raft solution culture, plants are placed in a sheet of buoyant plastic that is floated on the surface of the nutrient solution. That way, the solution level never drops below the roots. Aeration is the process by which air is circulated through, mixed with or dissolved in a liquid (usually water) or substance (such as soil). ... An electrical conductivity meter. ... Mariottes Bottle Mariotte’s bottle (after Edme Mariotte (1620-1684) a French physicist) is a device that provides a constant pressure that will deliver a constant rate of flow from closed bottles or tanks. ...

Continuous flow solution culture

In continuous flow solution culture the nutrient solution constantly flows past the roots. It is much harder to automate than the static solution culture because sampling and adjustments to degree and nutrient concentrations can be made in a large storage tank that serves potentially thousands of plants. A popular variation is the nutrient film technique or NFT whereby a very shallow stream of water containing all the dissolved nutrients required for plant growth is recirculated past the bare roots of plants in a watertight gully, also known as channels. Ideally, the depth of the recirculating stream should be very shallow, little more than a film of water, hence the name 'nutrient film'. This ensures that the thick root mat, which develops in the bottom of the channel, has an upper surface which, although moist, is in the air. Subsequently, there is an abundant supply of oxygen to the roots of the plants. A properly designed NFT system is based on using the right channel slope, the right flow rate and the right channel length. The main advantage of the NFT system over other forms of hydroponics is that the plant roots are exposed to adequate supplies of water, oxygen and nutrients. In all other forms of production there is a conflict between the supply of these requirements, since excessive or deficient amounts of one results in an imbalance of one or both of the others. NFT, because of its design, provides a system where all three requirements for healthy plant growth can be met at the same time, providing the simple concept of NFT is always remembered and practised. The result of these advantages is that higher yields of high quality produce are obtained over an extended period of cropping. A downside of NFT is that it has very little buffering against interruptions in the flow e.g. power outages, but overall, it is probably one of the more productive techniques.

The same design characteristics apply to all conventional NFT systems. While slopes along channels of 1:100 have been recommended, in practice it is difficult to build a base for channels that is sufficiently true to enable nutrient films to flow without ponding in locally depressed areas. Consequently, it is recommended that slopes of 1:30 to 1:40 are used. This allows for minor irregularities in the surface but, even with these slopes, ponding and waterlogging may occur. The slope may be provided by the floor, or benches or racks may hold the channels and provide the required slope. Both methods are used and depend on local requirements, often determined by the site and crop requirements.

As a general guide, flow rates for each gully should be 1 litre per minute. At planting, rates may be half this and the upper limit of 2L/min appears about the maximum. Flow rates beyond these extremes are often associated with nutritional problems. Depressed growth rates of many crops have been observed when channels exceed 12 metres in length. On rapidly growing crops, tests have indicated that, while oxygen levels remain adequate, nitrogen may be depleted over the length of the gully. Consequently, channel length should not exceed 10-15 metres. In situations where this is not possible, the reductions in growth can be eliminated by placing another nutrient feed half way along the gully and reducing flow rates to 1L/min through each outlet.


Main article: Aeroponics

Aeroponics is defined as a system where roots are continuously or discontinuously in an environment saturated with fine drops (a mist or aerosol) of nutrient solution. The method requires no substrate and entails growing plants with their roots suspended in a deep air or growth chamber with the roots periodically wetted with a fine mist of atomized nutrients. Excellent aeration is the main advantage of aeroponics. Close-up of lettuce and wheat grown in an aeroponic (air-culture) apparatus, NASA1998 Aeroponics is the process of growing plants in an air or mist environment without the use of soil or an aggregate media. ...

Aeroponic techniques have proved very successful for propagation, but have yet to prove themselves on a commercial scale. Aeroponics is also widely used in laboratory studies of plant physiology. Aeroponic techniques have been given special attention from NASA since a mist is easier to handle than a liquid in a zero gravity environment. For other uses, see NASA (disambiguation). ...

Passive subirrigation

Main article: Passive hydroponics

Passive subirrigation, also known as passive hydroponics or semi-hydroponics, is a method where plants are grown in an inert porous medium that transports water and fertilizer to the roots by capillary action from a separate reservoir as necessary, reducing labor and providing a constant supply of water to the roots. In the simplest method, the pot sits in a shallow solution of fertilizer and water or on a capillary mat saturated with nutrient solution. The various hydroponic media available, such as expanded clay and coconut husk, contain more air space than more traditional potting mixes, delivering increased oxygen to the roots, which is important in epiphytic plants such as orchids and bromeliads, whose roots are exposed to the air in nature. Additional advantages of passive hydroponics are the reduction of root rot and the additional ambient humidity provided through evaporation. In English, to be inert is to be in a state of doing little or nothing. ... A pore, in general, is some form of opening, usually very small. ... Capillary Flow Experiment to investigate capillary flows and phenomena onboard the International Space Station Capillary action, capillarity, capillary motion, or wicking is the ability of a substance to draw another substance into it. ... This article does not cite any references or sources. ... Orchid redirects here. ... Subfamiles Bromelioideae Pitcairnioideae Tillandsioideae Bromeliaceae (the bromeliads) is a large family of flowering plants native to the tropical and warm temperate New World. ...

Ebb and flow / Flood and drain subirrigation

Main article: Ebb and flow

In its simplest form, there is a tray above a reservoir of nutrient solution. The tray is either filled with growing medium (clay granules being the most common) and planted directly, or pots of medium stand in the tray. At regular intervals, a simple timer causes a pump to fill the upper tray with nutrient solution, after which the solution drains back down into the reservoir. This keeps the medium regularly flushed with nutrients and air. Ebb and Flow or Flood and Drain is a form of hydroponics that is known for its simplicity, reliability of operation, and low initial investment, while providing the advantages of hydroponics. ...

Top irrigation

In top irrigation, nutrient solution is periodically applied to the medium surface. This may be done manually once per day in large containers of some media, such as sand. Usually, it is automated with a pump, timer and drip irrigation tubing to deliver nutrient solution as frequently as 5 to 10 minutes every hour.

Deep water culture

Main article: Deep water culture

The hydroponic method of plant production by means of suspending the plant roots in a solution of nutrient rich, oxygenated water. Traditional methods favor the use of plastic buckets and large containers with the plant contained in a net pot suspended from the centre of the lid and the roots suspended in the nutrient solution. This article, image, template or category belongs in one or more categories. ...


Main article: Organoponics

Organoponics is a hydroponic system converted to organic cultivation by replacing the inorganic fertilizer with compost made from sugar waste. In a hydroponic system the roots need to be able to absorb nutrients as they touch the roots' hairs. There is no soil for organic fertilizer to sit in and release nutrients. So far, many chemical additives and root stimulators have done a great job adding nutrients to the plant through hydroponic gardening. Some claim that soil grown plants produce better tasting and possibly more nutritious food than hydroponically grown plants although this statement is not proven.[1] Organoponics is a term most common in LatinAmerica. ...


One of the most obvious decisions hydroponicists have to make is which medium they should use. Different media are appropriate for different growing techniques.


Diahydro is a natural sedimentary rock medium that consists of the fossilized remains of diatoms. Diahydro is extremely high in Silica (87-94%), an essential component for the growth of plants and strengthening of cell walls. Diatoms are the most common of the eukaryotic algae. ...

Expanded clay

Hydroton brand expanded clay pebbles.
Hydroton brand expanded clay pebbles.

Also known as 'Hydroton' or 'leca' (light expanded clay aggregate), trademarked names, these small, round baked spheres of clay are inert and are suitable for hydroponic systems in which all nutrients are carefully controlled in water solution. The clay pellet is also inert, pH neutral and do not contain any nutrient value. Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2304 × 1728 pixels, file size: 831 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2304 × 1728 pixels, file size: 831 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ...

The clay is formed into round pellets and fired in rotary kilns at 1200°C. This causes the clay to expand, like popcorn, and become porous. It is light in weight, and does not compact over time. Shape of individual pellet can be irregular or uniform depending on brand and manufacturing process. The manufacturers consider expanded clay to be an ecologically sustainable and re-usable growing medium because of its ability to be cleaned and sterilized, typically by washing in solutions of white vinegar, chlorine bleach or hydrogen peroxide (H2O2), and rinsing completely.

Another viewpoint is clay pebbles are best not re-used even when they are cleaned due to root growth which may enter the medium. Breaking open a clay pebble after a crop has been grown will reveal this. However, this view is generally not widely shared.


Rockwool is probably the most widely used medium in hydroponics. Made from basalt rock it is heat-treated at high temperatures then spun back together like candy floss. It comes in lots of different forms including cubes, blocks, slabs and granulated or flock. Mineral wool, also known as mineral cotton, silicate cotton, stone wool, slag wool, rockwool, and rock wool, is an inorganic substance used for insulation and filtering. ... For the cities, see Basalt, Colorado and Basalt, Idaho. ... Cotton Candy (also known as candy floss or fairy floss) is a form of spun sugar that is produced in a special machine and sold at fairs. ...

Rockwool is an excellent inert substrate for both 'free drainage' and recirculating systems. In free drainage or run-to-waste systems, the chance of disease spread is greatly lessened. Rockwool is also lightweight and self-contained, which allows plants to be grown at different densities in different stages - young plants can be grown to an advanced stage in a small area before being planted out into the main growing area, thus improving crop turnaround. Its light weight also permits setting up to be quick and inexpensive. Because it is light and rigid it eliminates back-breaking work in preparation and planting and gives substantial labor-saving costs. Rockwool is noted for providing a favourable root environment, thus minimizing plant stress. Root temperature can also be controlled, thus giving substantial energy savings. Rockwool initially causes an increase in pH level. You must adjust the pH level of the nutrient solution to counteract this. A pH level of 5.5-6.5 should suffice to create a suitable pH. For other uses, see PH (disambiguation). ...

The disadvantages of rockwool are few. Although relatively inexpensive, because of its bulk, transport costs to remote regions can be prohibitive. However, the fact that it can be used several times over will reduce the growers overall costs. Before handling, gloves and long shirt sleeves should be worn to prevent minor skin irritation. This can also be lessened by wetting the rockwool before handling. When this medium is dry, care needs to be taken so as not to inhale any particles; inhaling such particles may carry a health risk.


Coco peat, also known as coir or coco, is the leftover material after the fibres have been removed from the outermost shell (bolster) of the coconut. It took 10 centuries to make this waste a viable plant substrate. The first description of the coco process dates from the 11th century and was recorded by Arabian traders. In 1290, Marco Polo described the process of extracting fibres from coconuts. For centuries, this process remained unchanged. Coco peat was a waste product from factories that used coco fibre as a raw material for making sailing ropes, chair seats and mattress fillings. Coir (from Malayalam kayar, cord) is a coarse fibre extracted from the fibrous outer shell of a coconut. ...

Coco is a 100% natural grow and flowering medium, which has proven its value across years and years. Coco is not only a high quality product, but also an environmentally friendly product[citation needed]. For many years the raw material was considered waste material, and enormous useless “Coco Mountains” appeared in the landscapes of countries like Sri Lanka and India. By developing a special biological composting process this “waste” transformed into a high quality product. This innovation was, and still is, an important contributor to the local economy of India and Sri Lanka. This and the unique growth characteristics ensure coco is the medium of the moment and the future.

The coco substrate is an environmentally friendly product. No energy wasteful production methods are used during the production of this long-lasting cultivation medium. Coconut fibres are obtained from the coconuts’ husks which are a natural product that can be harvested throughout the year. Coir comes in bags and in slabs.

Some types of coir are very high in sodium (salt) due to the nature of coconut palms growing on island environments and being processed in the salt air. Quality coir has not been sterilized or heat treated and so retains its natural sponge-like qualities as well as the natural, beneficial trichoderma fungi which has been scientifically shown[citation needed] to combat root rot and other diseases.[citation needed] Trichoderma is also well-known for promoting root growth.[citation needed] Diversity about 35 species; see List of Trichoderma species Trichoderma are in nearly all soils, where they are the most prevalent culturable fungi. ...

This substrate combines the tolerant, organic nature of soil with the precision of rockwool. Due to the special characteristics of the substrate the nutrient doesn’t have a grow and flower variant, there is just one unique formulation for both growth and blooming phase. Due to the unique buffering capability of the coir substrate, and its sponge-like structure, the nutrients needed to ensure high yields are stored in the coco. This means that the plant itself can regulate the amount and timing of its nutrient intake.

Coconut fibres have sufficient capillary action to retain enough water and nutrients. This means that the plant can go for longer periods with-out water, which could happen if a feeding pump was to break down for example.

Quality coir can be used a number of times and makes an excellent soil improver after use.


Perlite is a volcanic rock that has been superheated into very lightweight expanded glass pebbles. It is used loose or in plastic sleeves immersed in the water. It is also used in potting soil mixes to decrease soil density. Perlite has similar properties and uses to vermiculite but generally holds more air and less water. If not contained, it can float if flood and drain feeding is used. Expanded Perlite Perlite is an amorphous volcanic glass that has a relatively high water content. ... Vermiculite is a natural, non toxic mineral that expands with the application of heat. ...


Like perlite, vermiculite is another mineral that has been superheated until it has expanded into light pebbles. Vermiculite holds more water than perlite and has a natural "wicking" property that can draw water and nutrients in a passive hydroponic system. If too much water and not enough air surrounds the plants roots, it's possible to gradually lower the medium's water-retention capability by mixing in increasing quantities of perlite. Vermiculite is a natural, non toxic mineral that expands with the application of heat. ...


Sand is cheap and easily available. However, it is heavy, it does not always drain well, and it must be sterilized between use.


The same type that is used in aquariums, though any small gravel can be used, provided it is washed first. Indeed, plants growing in a typical traditional gravel filter bed, with water circulated using electric powerhead pumps, are in effect being grown using gravel hydroponics. Gravel is inexpensive, easy to keep clean, drains well and won't become waterlogged. However, it is also heavy, and if the system doesn't provide continuous water, the plant roots may dry out.

Brick Shards

Brick shards have similar properties to gravel. They have the added disadvantages of possibly altering the pH and requiring extra cleaning before reuse.

Polystyrene packing peanuts

Polystyrene packing peanuts are inexpensive, readily available, and have excellent drainage. However, they can be too lightweight for some uses. They are mainly used in closed tube systems. Note that polystyrene peanuts must be used; biodegradable packing peanuts will decompose into a sludge. Plants may absorb styrene and pass it to their consumers; this is a possible health risk. Foam peanuts Foam peanuts, also known as packing peanuts, are a common loose-fill packing material which is also used to prevent damage to fragile objects during shipping. ... For other uses, see Polystyrene (disambiguation). ... C8H8 redirects here. ...

Nutrient solutions

Plant nutrients are dissolved in the water used in hydroponics and are mostly in inorganic and ionic form. Primary among the dissolved cations (positively-charged ions) are Ca2+ (calcium), Mg2+ (magnesium), and K+ (potassium); the major nutrient anions in nutrient solutions are NO3 (nitrate), SO42− (sulfate), and H2PO4 (phosphate). A nutrient is a substance used in an organisms metabolism which must be taken in from the environment. ... This article is about the electrically charged particle. ... For other uses, see Calcium (disambiguation). ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... Trinitrate redirects here. ... The sulfate anion, SO42− The structure and bonding of the sulfate ion In inorganic chemistry, a sulfate (IUPAC-recommended spelling; also sulphate in British English) is a salt of sulfuric acid. ... A phosphate, in inorganic chemistry, is a salt of phosphoric acid. ...

Numerous 'recipes' for hydroponic solutions are available. Many use different combinations of chemicals to reach similar total final compositions. Commonly-used chemicals for the macronutrients include potassium nitrate, calcium nitrate, potassium phosphate, and magnesium sulfate. Various micronutrients are typically added to hydroponic solutions to supply essential elements; among them are Fe (iron), Mn (manganese), Cu (copper), Zn (zinc), B (boron), Cl (chlorine), and Ni (nickel). Chelating agents are sometimes used to keep Fe soluble. Many variations of the nutrient solutions used by Arnon and Hoagland (see above) have been styled 'modified Hoagland solutions' and are widely used. R-phrases   S-phrases   Supplementary data page Structure and properties n, εr, etc. ... Calcium nitrate, also called Norgessalpeter (Norwegian saltpeter) and Kalksalpeter, is a white coloured soluble salt with the formula Ca(NO3)2. ... Magnesium sulfate (or sulphate) is a chemical compound containing magnesium and sulfate, with the formula MgSO4. ... General Name, symbol, number iron, Fe, 26 Chemical series transition metals Group, period, block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... For other uses, see Copper (disambiguation). ... General Name, symbol, number zinc, Zn, 30 Chemical series transition metals Group, period, block 12, 4, d Appearance bluish pale gray Standard atomic weight 65. ... For other uses, see Boron (disambiguation). ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... For other uses, see Nickel (disambiguation). ... Chelation (from Greek χηλή, chelè, meaning claw) is the process of reversible binding of a ligand, the chelator or chelating agent, to a metal ion, forming a metal complex, the chelate. ...

Plants will change the composition of the nutrient solutions upon contact by depleting specific nutrients more rapidly than others, removing water from the solution, and altering the pH by excretion of either acidity or alkalinity. Care is required not to allow salt concentrations to become too high, nutrients to become too depleted, or pH to wander far from the desired value. For other uses, see PH (disambiguation). ...


A miniature garden using hydroponics and aeroponics.
A miniature garden using hydroponics and aeroponics.

Due to its arid climate, Israel has developed advanced hydroponic technology. They have marketed their system to Nicaragua, which uses it to produce more than one million pounds of peppers annually for sale abroad, including the United States. Binomial name Capsicum annuum L. For green peppercorns, see Black pepper. ...

The largest commercial hydroponics facility in the world is Eurofresh Farms in Willcox, Arizona, which sold 125 million pounds of tomatoes in 2005.[2] Eurofresh has 256 acres under glass and represents about a third of the commercial hydroponic greenhouse area in the U.S. [3] Eurofresh does not consider their tomatoes organic, but they are pesticide-free. They are grown in rockwool with top irrigation. Willcox is a city in Cochise County, Arizona, United States. ...

Some commercial installations use no pesticides or herbicides, preferring integrated pest management techniques. There is often a price premium willingly paid by consumers for produce which is labeled "organic". Some states in the USA require soil as an essential to obtain organic certification. There are also overlapping and somewhat contradictory rules established by the US Federal Government, so some food grown with hydroponics can be certified organic. A cropduster spreading pesticide. ... An herbicide is used to kill unwanted plants. ... IPM bollworm trap Cotton field Manning, South Carolina In agriculture, Integrated Pest Management (IPM) is a pest control strategy that uses an array of complementary methods: natural predators and parasites, pest-resistant varieties (see GMO), cultural practices, biological controls, various physical techniques, and pesticides as a last resort. ... Organic farming is a psuedoscientific form of agriculture which avoids or largely excludes the use of synthetic fertilizers and pesticides, plant growth regulators, and livestock feed additives. ... Mixed organic bean sprouts Organic certification is a certification process for producers of organic food and other organic agricultural products. ... Organic farming is a psuedoscientific form of agriculture which avoids or largely excludes the use of synthetic fertilizers and pesticides, plant growth regulators, and livestock feed additives. ...

Hydroponics also saves an incredible amount of water; it uses as little as 1/20 the amount as a regular farm to produce the same amount of food. The water table can be impacted by the water use and run-off of chemicals from farms, but hydroponics may minimize impact as well as having the advantage that water use and water returns are easier to measure. This can save the farmer money by allowing reduced water use and the ability to measure consequences to the land around a farm. Cross section showing the water table varying with surface topography as well as a perched water table The water table or phreatic surface is the surface where the water pressure is equal to atmospheric pressure. ... Run-off or runoff may refer to one of the following. ...

The environment in a hydroponics greenhouse is tightly controlled for maximum efficiency and this new mindset is called Soil-less/Controlled Environment Agriculture (S/CEA). With this growers can make ultra-premium foods anywhere in the world, regardless of temperature and growing seasons. Growers monitor the temperature, humidity, and pH level constantly. The Royal Greenhouses of Laeken. ... Controlled Environment Agriculture (CEA) is any agricultural technology that enables the grower to manipulate a crops environment to the desired conditions. ... For other uses, see PH (disambiguation). ...

Hydroponics have been used to enhance vegetables to provide more nutritional value. A hydroponic farmer in Virginia has developed a calcium and potassium enriched head of lettuce, scheduled to be widely available in April 2007. Grocers in test markets have said that the lettuce sells "very well", and the farmers claim that their hydroponic lettuce uses 90% less water than traditional soil farming.[4] This article is about the U.S. state. ... For other uses, see Calcium (disambiguation). ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ...

Scientific literature

Scientific literature on hydroponics can be found in various journals, including Annals of Botany, New Phytologist, Plant and Soil and Plant Physiology. Annals of Botany is a monthly scientific journal (ISSN 0305-7364) that publishes research articles, brief communications, and reviews in all areas of plant science. ... The following is a list of botanical journals and magazines Acta Botanica Gallica Acta Botánica Mexicana Acta Botanica Yunnanica Acta Phytotaxonomica Geobotanica Acta Phytotaxonomica Sinica Adansonia American Journal of Botany Annales Forestales (Anali za Sumarstvo, Zagreb) Annals of Botany Annals of the Missouri Botanical Garden Arboretum Kórnickie Arnoldia... Plant and Soil is an international peer-reviewed English language journal that publishes original research into topics related to the relationships between plants and soil, such as relationships and interactions of plants with minerals, water and microbes, the anatomy and morphology of roots, soil biology and ecology, and so on. ... Plant Physiology (ISSN 00320889) is a peer-reviewed scientific journal that publishes articles on the physiology, biochemistry, cellular and molecular biology, genetics, biophysics, and environmental biology of plants. ...

Present and future

With pest problems reduced, and nutrients constantly fed to the roots, productivity in hydroponics is high, plant growth being limited by the low levels of carbon dioxide in the atmosphere, or limited light. To increase yield further, some sealed greenhouses inject carbon dioxide into their environment to help growth (CO2 enrichment), or add lights to lengthen the day, control vegetative growth etc. Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...

This technology allows for growing where no one has grown before, be it underground, or above, in space or under the oceans this technology will allow humanity to live where humanity chooses. If used for our own survival or our colonisation, hydroponics is and will be a major part of our collective future. [5]

See also

Close-up of lettuce and wheat grown in an aeroponic (air-culture) apparatus, NASA1998 Aeroponics is the process of growing plants in an air or mist environment without the use of soil or an aggregate media. ... // Aquatic animal effluent (for example fish waste) accumulates in water as a byproduct of keeping them in a closed system or tank (for example a recirculating aquaculture system). ... // Plants can be grown indoors year round using a stealth grow box. ... There are very few or no other articles that link to this one. ...


  1. ^ Medicinal Marijuana Horticulture, Jorge Cervantes; copyright 2007, Van Patten Publishing
  2. ^ Kenney, Brad P. 2006. Success under glass. American Vegetable Grower. May, pages 12-13.[1]
  3. ^ Sorenson, Dan. 2006. Hydroponic tomatoes. Arizona Daily Star [2]
  4. ^ Murphy, Katie. 2006. Farm Grows Hydroponic Lettuce. Observer Online [3]
  5. ^ Winterborne J, 2005. Hydroponics - Indoor Horticulture [4]

External links

  Results from FactBites:
Hydroponics (215 words)
Hydroponic growing has become a major player because of its ability to be used where the ground or climate in the region can't normally support the growing of plant life.
This can be a desert or even a space station, but hydroponic technology is used mainly by greenhouses and home hobbyists as a way of quickly raising plants to maturity.
Because of hydroponics, the home hobbyist is now able to grow crops of the highest quality many times a year in a relatively small area.
Hydroponics - Wikipedia, the free encyclopedia (3699 words)
Hydroponics is also a standard technique in biology research and teaching and a popular hobby.
Hydroponics is often the best crop production method in remote areas that lack suitable soil, such as Antarctica, space stations, space colonies or atolls, such as Wake Island.
Plant nutrients are dissolved in the water used in hydroponics and are mostly in inorganic and ionic form.
  More results at FactBites »



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