# Hydroculture/Printable version

The current, editable version of this book is available in Wikibooks, the open-content textbooks collection, at
https://en.wikibooks.org/wiki/Hydroculture

# History

This is a history of notable hydroculture phenomena. Ancient hydroculture proposed sites, and modern revolutionary works are mentioned. Included in this history are all forms of aquatic and semi-aquatic based horticulture that focus on flora: aquatic gardening, semi-aquatic crop farming, hydroponics, aquaponics, passive hydroponics, and modern aeroponics.

## Hanging Gardens of Babylon

One of the wonders of the ancient world, was irrigated by the Euphrates River. It is uncertain if Sammu-ramat or Nebuchadrezzar II ordered them to be built between 8th and 7th century BC Babylonia. The gardens were built partially on top of ziggurats, and plants were irrigated on channels. No direct evidence of the Hanging Gardens of Babylon exists. However, there is archeological evidence, uncovered by Robert Koldewey, that ancient structures exist to support the technology used for these gardens.
Ancient Greeks Diodorus Siculus and Strabo have noted the Hanging Babylonian Gardens.

## Precolonial America

A Chinampa is a floating garden armada in a lake from the Xochimilco region, once Chinampan, of Mexico. This floating garden, still in use, can have an area of up to 10 meters by 200 meters. The agricultural output of the chinampa allowed the postclassic Aztec civilization to flourish.

## Historical Orient

Historically, fish have been raised within flooded rice fields in Indochina and China.

## Living root bridges

There are 500 year old bridges made by living roots in India, sculpted by the War-Khasis. These trees span rivers, and may be limited in connectivity to hydroculture.

## Hydroculture found in nature

Orchids are well known for their aerial roots.
Ōhi'a Lehua, Metrosideros polymorpha, is a Hawaiian plant with roots that can grow suspended in extinct lava tubes. The roots of this plant are able to penetrate deep into the volcanic rock, to reach these hollow tubes, where they can collect moisture.

## See also

* Botanical garden history
* w:History of agriculture
* w:History of gardening
* w:Horticulture
* Incan agriculture
* w:Water garden

## References

* 1 2 3 4 5 University of Chicago, ed (1993). "Hanging Gardens of Babylon". Britannica. 5 (15 ed.). Chicago: Encyclopaedia Britannica Inc. pp. 681–682.
* 1 2 University of Chicago, ed (1993). "Chinampa". Britannica. 3 (15 ed.). Chicago: Encyclopedia Britannica Inc. pp. 231.
* ↑ McMurtry, M. R., Nelson, P.V., & Sanders, D.C. (1988). Aqua-vegeculture systems. International Ag-Sieve, 1(3), article 7.
* ↑ "Living Bridges in India Have Grown for 500 Years (Pics)". w:TreeHugger, New York. Retrieved December 20, 2012.
* ↑ "Hawaii". Cambell Scott, David Allen, Mike Slee, Paul Spillenger. Atlas 4D. Discovery, USA. August 2010.

# Physiology/Rhizosphere

Roots must breathe oxygen. There is a limit to the amount of dissolved gasses that can be contained in water. Aquatic plant roots do not need direct access to oxygen in the water or medium, because these plants are adapted to transport oxygen throughout its physiological system.

## Rhizosphere

The rhizosphere is the narrow region around the root that is directly influenced by root secretions and associated microorganism. The rhizosphere contains many bacteria that feed on sloughed-off plant cells, termed rhizodeposition, and the proteins and sugars released by roots. Protozoa and nematodes that graze on bacteria are also more abundant in the rhizosphere. Thus, much of the nutrient cycling and disease suppression needed by plants occurs immediately adjacent to roots.

## Secretions and endophytes

Plants secrete many compounds into the rhizosphere which serve different functions. Strigolactone, secreted and detected by mycorhizal fungi, stimulate the germination of spores and initiate changes in the mycorhiza that allow it to colonize the root. Symbiotic Nitrogen-fixing bacteria, such as the Rhizobium species, detect an unknown compound secreted by the roots of leguminous plants and then produce nod factors which signal to the plant that they are present and will lead to the formation of root nodules, in which the bacterium, sustained by nutrients from the plant, converts nitrogen gas to a form that can be used by the plant. Non-symbiotic (or "free-living") nitrogen-fixing bacteria may reside in the rhizosphere just outside the roots of certain plants (including many grasses), and similarly "fix" nitrogen gas in the nutrient-rich plant rhizosphere. Even though these organisms are thought to be only loosely associated with plants they inhabit, they may respond very strongly to the status of the plants. For example, nitrogen-fixing bacteria in the rhizosphere of the rice plant exhibit diurnal cycles that mimic plant behavior, and tend to supply more fixed nitrogen during growth stages when the plant exhibits a high demand for nitrogen.

## See also

* w:Mucigel
* w:endophyte
* w:Trichoderma

## References

* ↑ Template:Cite DOI
* ↑ "Microbial Health of the Rhizosphere". Retrieved 5 May 2006.
* ↑ "The Soil Food Web". USDA-NRCS. Retrieved 3 July 2006.
* ↑ Sims GK, Dunigan EP (1984). "Diurnal and seasonal variations in nitrogenase activity (C2H2 reduction) of rice roots". Soil Biology and Biochemistry. 16 (1): 15–18. doi:10.1016/0038-0717(84)90118-4.

## Further reading

* "The Soil Habitat". University of Western Australia. Retrieved 3 July 2006.
* Digging in the Dirt: Is the Study of the Rhizosphere Ripe for a Systems Biology Approach? - A review from the Science Creative Quarterly (retrieved 4 December 2006)

# Aeration

Oxygenation is important to the sustainability of a hydroculture ecosystem. Plant roots, aerobic bacteria, hydrophytes, fish and or other aerobic organisms and tissue require oxygenation.
Insufficient oxygen (environmental hypoxia) may occur in water or substrate, creating a hazardous environment for aerobic organisms and tissue. Deoxygenation increases the relative population of anaerobic organisms such as certain bacteria, resulting in root rot, fish kills and other adverse events. Increasing the concentration of aerobic conditions provides a a healthy hydroculture ecosystem.
Water aeration is required in water bodies that suffer from anoxic conditions. Aeration can be achieved by using an air pump with a diffuser, or by surface agitation from a fountain or spray-like device to allow for oxygen exchange at the surface and the release of noxious gases such as carbon dioxide, methane or hydrogen sulfide.
Dissolved oxygen (DO) is a major contributor to water quality. Not only do fish and other aquatic animals need it, but oxygen breathing aerobic bacteria decompose organic matter. When oxygen concentrations become low, anoxic conditions may develop which can decrease the ability of the water body to support life.

## Hypoxia

Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen (DO; molecular oxygen dissolved in the water) becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system. Dissolved oxygen is typically expressed as a percentage of the oxygen that would dissolve in the water at the prevailing temperature and salinity (both of which affect the solubility of oxygen in water; see oxygen saturation and underwater). An aquatic system lacking dissolved oxygen (0% saturation) is termed anaerobic, reducing, or anoxic; a system with low concentration—in the range between 1 and 30% saturation—is called hypoxic or dysoxic. Most fish cannot live below 30% saturation. A "healthy" aquatic environment should seldom experience less than 80%. The exaerobic zone is found at the boundary of anoxic and hypoxic zones.

## Aeration methods

Here are ways of infusing air into the nutrient solution and aquaponic tank. Also, keeping the plant roots suspended above the nutrient solution is beneficial, since there is a limit to the amount of oxygen saturation that can be contained in water.

### Fountains

Fountains aerate by pulling water from the surface of the water and propelling it into the air.
This process utilizes air-water contact to transfer oxygen. As the water is propelled into the air, it breaks into small droplets. Collectively, these small droplets have a large surface area through which oxygen can be transferred. Upon return, these droplets mix with the rest of the water and thus transfer their oxygen back to the ecosystem.
Fountains are a popular method of surface aerators because of the aesthetic appearance that they offer. However, most fountains are unable to produce a large area of oxygenated water.

### Fine bubble aeration

Fine bubble aeration is an efficient way to transfer oxygen into water. Attached to the unit are a number of diffusers. These bubbles are known as fine bubbles. The EPA defines a fine bubble as anything smaller than 2mm in diameter.
Fine bubble diffused aeration is able to maximize the surface area of the bubbles and thus transfer more oxygen into water per bubble. Additionally, smaller bubbles take more time to reach the surface so not only is the surface area maximized but so are the number of seconds each bubble spends in the water, allowing it more time to transfer oxygen to the water. As a general rule, smaller bubbles and a deeper release point will generate a greater oxygen transfer rate.
However, almost all of the oxygen dissolved into the water from an air bubble occurs when the bubble is being formed. Only a negligible amount occurs during the bubbles transit to the surface of the water. This is why an aeration process that makes many small bubbles is better than one that makes fewer larger ones. The breaking up of larger bubbles into smaller ones also repeats this formation and transfer process.
One of the drawbacks to fine bubble aeration is that the membranes of ceramic diffusers can sometimes clog and must be cleaned in order to keep them working at their optimum efficiency. Also, they do not possess the ability to mix as well as other aeration techniques, such as coarse bubble aeration.

### Drain

In certain types of hydroculture, such as flood drain systems, water can be cycled to frequently drain away from the hydroculture system. Plant roots suspended in air provides them aeration that can not be accomplished by allowing plant roots to be saturated in water.

## Measurement

In aquatic environments, oxygen saturation is a relative measure of the amount of oxygen (O$_2$) dissolved in the water. Supersaturation can sometimes be harmful for organisms and cause decompression sickness. Dissolved oxygen (DO) is measured in standard solution units such as millilitres O$_2$ per liter (ml/L), millimoles O$_2$ per liter (mmol/L), milligrams O$_2$ per liter (mg/L) and moles O$_2$ per cubic meter (mol/m$^3$). For example, in freshwater under atmospheric pressure at 20°C, O$_2$ saturation is 9.1 mg/L.

## References

* 1 2 Tucker, Craig. "Pond Aeration." Pond Aeration SRAC Factsheet 3007
* ↑ "Lake Aeration and Circulation" (PDF). Illinois Environmental Protection Agency. Retrieved 13 September 2009.
* ↑ Taparhudee, Wara. "Applications of Paddle Wheel Aerators and Diffused-Air System in Closed Cycle Shrimp Farm System." 2002.
* ↑ http://users.vcnet.com/rrenshaw/do.html

# Root/Rot

Phytopathology is the study of plant diseases.

## Root rot

Root rot is a condition that occurs, because of poor aeration and microbial, especially water mold problems. Dead roots allow rot to spread throughout the plant. This can be a result of inadequate oxygenation, sanitation and stagnation. It is usually lethal, since there is no certain effective treatment. The effectiveness of predator fungus remains in question.
The excess water makes it very difficult for the roots to get the air that they need, causing them to decay.
Root rot is commonly caused by members of the water mold genus Phytophthora. Perhaps the most aggressive is P. cinnamomi. Spore from root rot causing agents do contaminate other plants, but the rot cannot take hold unless there is adequate moisture. Spores are not only airborne, but are also carried by insects and other arthropod.
A plant with root rot will not normally survive, but can often be propagated so it will not be lost completely. Plants with root rot should be removed and destroyed.
Root rot can occur in hydroponic applications, if the water is not properly aerated. This is usually accomplished by use of an air pump with an air diffuser, or by allowing water to drain away from appropriate hydroculture systems frequently on a time cycle. Problems associated with poor water aeration were principal reasons for the development of aeroponics.

## Particular diseases

* w:Rhododendron root rot
* w:Shoestring root rot
* w:Texas root rot

## See also

* w:Pythium
* w:Plant pathology

## References

* Shurtleff, Malcolm C. (1962) How to Control Plant Diseases in Home and Garden Iowa State University Press, Ames, Iowa, p. 73;
* Yepsen, Roger B. Jr. (1976) Organic plant protection: a comprehensive reference on controlling insects and diseases in the garden, orchard and yard without using chemicals Rodale Press, Emmaus, PA, pp. 194, 208, 212-213, 226, 247, 260, 295, 321, 333, 337, 469, 488, 577, and 629, ISBN 0-87857-110-8 ;
* Ellis, Barbara W. and Bradley, Fern Marshall (eds.) (1992) The Organic gardener's handbook of natural insect and disease control: a complete problem-solving guide to keeping your garden & yard healthy without chemicals Rodale Press, Emmaus, PA, p. 401, ISBN 0-87596-124-X ;

# Substrates

Common hydroponic aggregates. Only materials that have a higher air to water retention ratio are included.

## Expanded clay

Expanded clay pellets are a common hydroculture substrate.

## Growstones

Growstones are a substrate for growing plants that can be used for soilless purposes or as a soil conditioner. This substrate is made from recycled glass. It has both more air and water retention space than perlite and peat. Another property of this medium is that it holds more water than parboiled rice hulls.
Growstones appear to be a comparable alternative to expanded clay aggregate.

## Parboiled rice hulls

Rice hulls that are parboiled (PBH) are a substrate or medium for gardening, including certain hydrocultures. This medium decays over time. Rice hulls allow drainage, and retain less water than growstones. A study showed that rice hulls don't affect the effects of plant growth regulators.

## Wood fiber

Wood fiber reduces the effects of growth suppressant hormones, used for uniform growth.

## Cocopeat

Coco fiber is a common hydroculture aggregate made from coconut hulls.

## Gravel

Gravel is good to be layered on the bottom. It allows better drainage near from the plastic net-pot. Placing seeds too close to plastic allows them to rot easier.

## References

* 1 2 (2011). "Growstones ideal alternative to perlite, parboiled rice hulls". American Society for Horticultural Science http://esciencenews.com/articles/2011/12/14/growstones.ideal.alternative.perlite.parboiled.rice.hulls
* ↑ Evans, Michael (2011). "Physical Properties of and Plant Growth in Peat-based Root Substrates Containing Glass-based Aggregate, Perlite, and Parboiled Fresh Rice Hulls". HortTechnology. 21 (1): 30–34. {{cite journal}}: Unknown parameter |month= ignored (help)
* 1 2 3 Wallheimer, Brian (October 25, 2010). "Rice hulls a sustainable drainage option for greenhouse growers". Purdue University. Retrieved August 30, 2012.

## External links

* Comparison to hydroton
* Growstones chart
* Growstones on YouTube

# Propagation

This helps with the understanding of hydroculture related plant propagation.

## Stem cutting

Stem cutting is an asexual method of propagation. Cut the stem by 10 inches long. Cut a green branch off of the desired plant above a node with a sterile cutting utensil. On the cut branch, trim off one or both sides, up to the length of next node. There should be one or two strips of bark running the length from below the bottom most node to the bottom of the cutting. Wet and dip this in rooting hormone if desired. Place the cutting into the aggregate. The more leaf area the cutting has, the more chances that the plant dries out, as a green stem is all that is necessary. Proper drainage is required: a substrate that has a higher water to air ratio attracts an-aerobic conditions and mold.
There are ways of improving the growth of stem cutting propagations. Intensifying light allows cuttings to root and sprout faster, apart from the concern that this could cause the propagation material distress. Azalea cuttings can be mildly heated in water to disinfect it from the fungus pathogen Rhizoctonia, and this could potentially be used for other plants.

## Seeds, bulbs and tubers

Large seeds, bulbs and tubers (potatoes, avocado seeds) proved to be hardier than smaller propagation material. Propagation material is very delicate to minute water qualities. These minute water qualities are trivial to aquatic animal health. Ideally, keep the fish and other aquatic animals stress-free.
Some seeds need to have their coating removed, because it is susceptible to rot. Removing the seed coat, on certain species, also allows for quicker propagation.

## Grafting

Grafting is not specific to hydroculture, but it may be used. A reason may be, to grow different varieties of a species of the same genus on one plant.

## References

* ↑ Wallheimer, Brian (January 23, 2012). "Study shines light on ways to cut costs for greenhouse growers". Lopez and Currey. Purdue University. Retrieved July 31, 2012.
* ↑ Yao, Stephanie (December 24, 2009). "Hot Water Treatment Eliminates Rhizoctonia from Azalea Cuttings". USDA Agricultural Research Service. Physorg. Retrieved July 31, 2012.

# Physiology/Aquatic

This is about aquaculture plant and symbiotic organisms in hydroculture systems: the focus is horticultural. Aquaponic and aquascaping organisms are covered in this section.

## Hydrophytes

Hydrophytes are aquatic plants. Aquatic plants can transport oxygen throughout its stem, unlike land plants. Hydrophytes need plenty of light, as in their natural environments.

### Semi-aquatic plants

Semi-aquatic plants are adapted to live with its root system in both submerged and land based environments. Only during this time, when a plant's root system is submerged it is involved in hydroculture. (cranberry and watercress)

## Symbiotic animals

Animals in aquaponics or aquaculture form a symbiotic relationship with plant-life. Aquatic animals need some light like in their natural environments.

### Freshwater

Goldfish, Loricariidae catfish, snails and shrimp eat algae.

### Plant-like animals

Coral are a saltwater animal that require high maintenance. There are freshwater and saltwater sponge.

## Aquascaping

Saltwater aquascaping is for aesthetic reasons. Coral, sponges and saltwater plants may (possibly) form a symbiotic relationship.
(Aquarium keeping, fishkeeping, other symbiotic animals and aquascaping)

## Aquatic gardening

garden ponds

# Nutrition

* Introduction Historical | Root zone | Nutrition DIY | Aquaponic | Passive
Following pertains to plant minerals and pH levels. Dilute 1 tablespoon of fertilizer in a gallon container with water at a time before adding to system. (Adding too little is safer than adding too much). For non-hydroponic fertilizers use 1/10 of the dosing on the label, with the amount of water in the container in mind. The hoagland solution provides a basic reference point. (Please do more research on this).

## Essential elements

Calcium, carbon, hydrogen, magnesium, nitrogen, oxygen, phosphorus, potassium, and sulfur are essential macro-elements. Oxygen, hydrogen, and carbon are obtained from water and air.
Nitrogen, phosphorus and sulfur can be fixed by certain endophyte bacteria.
Boron, chlorine, copper, iron, magnesium, molybdenum, zinc and possibly nickel are essential micro-nutrients.
Hard tap water contains many plant nutrients.

## Nonessential minerals

There are other minerals used or taken up by plants, but they are not considered essential. Some nonessential minerals are contaminants to plant or human health.

## pH

Sodium bicarbonate helps buffer pH levels, and fortunately some may already be present in tap water.

## Testing

Measuring the conductivity of the water (using a multimeter) is a way of analyzing the total dissolved solids. This indicates whether the water solution is within range, but this method doesn't test for nutrient imbalances. Test paper, or a pH and nutrient meter is required for more testing.

## Formulations

* 1 ppm=1 mg/l
The weight ratio of an essential element within a nutrient compound needs to be found, and the atomic weight of these elements and a chart is helpful to solve this.

### Hoagland solution

w:Hoagland solution

## Advisories

Do not add mineral tablets (except calcium?) not made for fertilizer purposes to the nutrient solution. The nutrient solution should be clear when the system is set up.

## References

* 1 2 3 4 5 6 7 8 9 Resh, Howard (1998). Hydroponics: Questions and Answers for successful growing. Mahwah, New Jersey: New Concept Press. ISBN 0-931231-96-5.

# Nutrition/Appendments
## Fertilizer methods

Dilute the nutrient solutions in a gallon of water before adding to the system. The water should always be clear after application. Initial nutrient solutions reference points:
* w:hoagland solution
* non-hydroponic fertilizers - use 1/10 of the label dosing, with the amount of water in the container in mind
* hydroponic fertilizers - labeled directions
* sterilized soil - sterilize fertile soil, then run it through a cheese cloth
* pH meter readability and EC by a multimeter
* aquaponic

## Natural fertilizer

Potting soil may be sterilized by heating in a covered container. This same soil can be run through a cloth to fertilize the nutrient solution. Only a little bit is needed, and making the water murky is disadvantageous to the nutrient solution.

## Aquaponic nutrition

Initially, nutrient solutions or fish establishment of the water is necessary for aquaponic gardening. New propagation tissue, like seeds and stem cuttings, can tolerate the lack of nutrients, until the levels build up from fish wastes. Aquatic animals do the work of maintaining proper plant nutrition and maintaining salt levels. Once fish are established, nutrient solutions are no longer necessary for maintaining aquaponic gardens, since fish waste provides all of the nutrients necessary. Adding nutrient solutions after this point can be detrimental to the plants, while this may not readily affect fish. In an aquaponic system, adding less fertilizer is safer than adding too much, especially since aquatic animals immediately make up for the difference.
If the water is changed, the correct nutrient solution has to be compensated. Rooted or established plants may quickly die of nutrient deficiencies.

## Supplements for plants

Aspirin, melatonin and rooting hormones may be beneficial to the plant.

## References

* ↑ "Plants feeling under the weather?: Give them aspirin water!". {{cite web}}: line feed character in |title= at position 35 (help)

# DIY

Here are common tools, instructions, and observations for hydroculture gardening.

## Common tools

* drill bit
* hole saw with guide drill (short guide drills can easily slip, while using a hole-saw)
* cutting utensil: gardening clippers (with proper care and measurement could also be used in place of a hole-saw)
* drill
** hex bit screwdriver: fits on end of drill bit or hole-saw to function as a hand-drill (impractical for use with large diameter hole-saws)
** or electric (not recommended with adjustable hole saws)
* pipe cutter
* pvc primer and cement

## Water tight seals

* Materials: 2 o-rings; 2 threaded pvc or metallic connectors
Put one o-ring on the male connection, place through hole in plastic material. Then add another o-ring, and screw on the female connector. Corresponding components must be of the same size. Connection must be snug. Check for drips.
Threaded fittings with o-rings can reduce or eliminate the need for pipe cement. If the desired threaded fitting is not available in pvc form, galvanized or brass fittings will connect to pvc fittings. Any metallic connector should be non-lead.

### Commonly used method

Pipe thread, or pvc primer and cement.

## Adding containers

Adding a second plastic container. Obviously both containers are to be at about the same level. Run a tube with required o-rings and threaded connectors between totes. Place halfway between bottom and water level, in case of a failure, not all of the water will drain out. Make sure this setup is watertight and ready before adding fish or plant setups. Water will transfer passively. A second air pump connection and an aeration stone is required in this setup.

### Connecting two aquatic containers together

This is a fancy setup for fish room and for fish to travel between containers. For this to work, the containers must be sturdy. If this aquaponics system is in a permanent spot, two cylindrical bins can possibly be connected together, side by side. Use 3" or wider diameter threaded coupling, four o-rings and two more threaded connectors. This setup must be watertight and safe from damage. Again, make the connections halfway from the bottom, in case of a leakage or damage failure.

## Electrical

Having separate timers for pumps, water pumps, and lighting.
Running DC made components on solar power.
Constructing a dc voltage timer in place of an expensive specific interval timer.

# Aero/Bucket

This is how to build a simple aeroponic bucket.

## Materials

All component materials should be nonhazardous/noncancerous. For tools and supplementary instructions see: hydroculture DIY
* 5 gallon bucket with lid
* pump: fountain
* pex tubing
* sprinkler head: grass type
* plastic grommet: larger than plug socket depending on configuration

## Process

Modification on the bucket is optional. Cut holes in the lid for net pots. Then cut a hole for a grommet, either in the lid or close to the top of the bucket. This is to protect the wire from damage that could cause an electrical hazard.
The water pump can be super-glued or tie wrapped to a heavy object to keep it from moving. Place water pump inside the bucket, thread the wire through the grommet. Water can spill out of here, so keep electrical connections higher than and away from this. The remaining space between the wire and the grommet can be filled in, without a material that can scratch or otherwise damage the electrical wire: cut a slit in a smaller grommet to fit around wire.
Fit pex tubing on water pump connector. Some grass sprinkler heads will fit inside of the pex tubing.
Now it is time for finishing touches.

# Aqua/Ponics1

This is a relatively easy and inexpensive way to make an easy top-drip aquaponic system. It is representative of a hybrid bubbleponics and aquaponics system.

## Materials

All component materials should be nonhazardous/noncancerous. For tools see: hydroculture DIY tools
* tote (or a 5 gallon bucket) with lid
* air pump, and tubing
* micro-tubing connectors
* basic timer with output plugin (enough to turn on for at least a few minutes 3 times a day)
* substrates: expanded clay, parboiled rice husks (I'm uncertain if growstones being of glass material are safe for aquarium animals)
* net-pots
* high lumen output light bulb: led (lamp or candelabra type may be practical)

## Plant and symbiotic animal life

* seeds, bulbs, stem cuttings
** chemical fertilizer (Apply 1 teaspoon for the whole system one time only, and this may not be necessary)
* hardy freshwater aquarium animals: goldfish, catfish algae eater, snails or shrimp
** algae wafers, and flakes

## Lid

Place net-pots upside-down on the tote-lid, and leave 1 inch in diameter in the center vacant for the pex tube to come through. Mark the outline and the center of the tote with a pencil. Use a marker to mark about 1/4in inside the circle. (The lip of the net-pot must rest on the lid) Use a (hand or power) drill, that is the same outer diameter as the pex pipe, to make a hole in the center of the lid. Cut holes out for the net-pots. (As mentioned before, make sure the hole is smaller than the outer diameter of the net-pot, so the net-pot won't fall through.)

## Airlift pump

The benefits using an air-pump is: that it is convenient to buy, that it is not allowed to be underwater causing an electrical hazard and that not a lot of water pressure is required in this system. The aquarium pump will sit higher than and outside the aquaponics unit, and it will serve the function of an airlift pump.
An airlift can be made with microtubing and a T connector. First, connect the middle part of the T to the air supply in. Then, connect a short length of microtubing to one end of the T, and the fountain out to the opposite end. A micro barb coupling can be inserted on the fountain end of the microtubing to allow a narrow opening to make the water sputter further. This can also be used to connect the fountain end of the microtubing to the top of the tote lid.
The water input should be lower than the air input, and a weight may be necessary. If done properly, once the tote is filled with water, the air will push the water up to spill on the top of the tote-lid.

## Timer

The timer only needs to be on to run the air pump enough to wet the substrate material, and needs to turn on a few times a day, at minimum for plant health. This eliminates the need for buying an expensive timer (required for a true aeroponic system), or having to build your own through dc circuitry. The substrate material does enough to keep the plant's roots moist between waterings. However, the timer should turn on often, or be left on without the timer, to aerate the fish and the tank and for improved plant growth. (a mechanical timer with settings for 30 or 15 minutes on/off will work) Plants need about 6 hours a day of darkness. Water falling back towards the tote aerates the water. Hook the timer to both the led (or fluorescent) light and air pump. Choose a bright light, and put the system near a window. (Its ok to have both turn on at the same time, allow the timer to turn on less often at night)

## Final steps

Wipe down inside of tote, cleaning up fragments. Add water and fertilizer solution (see above) to the tote. Use de-chlorinated water or let system run for a few minutes beforehand to de-chlorinate. Chlorine dissipates on contact with air, and chloramine takes longer to dissipate. Set in lid and net-pots. 1 net pot can be left out to let light in for the fish, but not too much light should be let in, for plant root health. Fill the net-pots halfway with substrate material. Add bulbs, stem cuttings or seeds. (Don't use plants dangerous to fish). Let plant stems grow before adding the rest of the material. Rockwool is not aerated enough, so it is ideal for balling around small seeds or layering around a stem cutting. Most material needs to be a porous. Coco-peat helps prevent fungus formation. Add goldfish, and feed them daily. Goldfish seem to graze on algae. Algae eaters, shrimp and snails are optional for cleaning up algae. The fish in this type of aquaponic system are hardier than plants. Once the fish are established they do the work of keeping the fertilizer level stable.

## See also

* Botany
* w:Ecoversity
* w:Limits To Growth
* w:Low-cost, tropical, private food production system
* w:Plant physiology
* w:Plant propagation
* w:Sustainability
* w:Vertical farming

# Aqua/Bin

This is a guide to modify a cylindrical container into an aquaponic fish or aquatic animal tank for inclusion in a hydroculture system. A barrel, over-sized bucket or new container (garbage) bin can be used to make this aquatic tank: containers that are over 30 gallons are ideal for this project. The purpose is to use ornamental fish waste to fertilize plants. Here are project assembly components to choose from.

## Components

All component materials should be nonhazardous/noncancerous. For tools and supplementary instructions see: hydroculture DIY
* cylindrical plastic container: new plastic recycle bin, barrel or over-sized bucket
* o-rings
* threaded elbow
* corresponding threaded adapters
* water pump
* washer with screen
* Additional pipe, o-rings and connectors: use 1/2in to 1in pipe and smaller tubing for water flow.
** smaller size tubing and pipes are suitable for drainage. 1in piping offers less restriction, and larger sizes are unnecessary for water flow.
* pipe primer and cement

## Aquatic tank

For an outdoor aquatic tank an overflow connection with a screen must be installed close to the top. Use two threaded fittings, with a washer with screen in between: it may not be necessary for this connection to be especially watertight.

## Water pump

High voltage water pumps can be a hazard if damaged or mishandled. BLDC pumps are efficient and usually operate on a much safer voltage. An airlift pump may also work, if the aquaponics system doesn't require high water pressure. Use wider diameter pipe to carry the water above the height of the tank, then it can be diverted into multiple smaller channels. No electrical connections or not watertight components may be exposed to water. Plug components higher than water-level or have a drip loop, so water does not drip into an electrical socket or other connection. The choices of how to transfer water from the aquatic tank to the plants are as follows.

### External

For an external water pump, a hole has to be cut into the side of the cylindrical container, 1/3 way from the bottom. This must b

### Internal

Make connections from water pump connection to wider diameter pipe, using proper connectors. The pump's electrical wire must be long enough, and it cannot be exposed to potential damage, and the connection away from potential water contact. On the side top of the aquatic tank, drill a hole to insert a threaded plug and o-ring from the outside. From the inside fit on pvc threaded snap tee, o-rings to the threaded plug. The snap tee is to hold the pipe attached to the pump vertically inside the tank.

### Airlift pump

For an airlift pump, smaller diameter pipe keeps air and water pressure higher allowing water to flow further. This can limit the height a water-flow can reach and water-flow pressure. Micro-sprinklers may be useful as micro-drippers in this case.

## Options
### Connect to other hydroculture systems

This aquaponic setup can be connected to an aeroponic or hydroponic system.

### Growbed

If the growbed or plant container is to be lower than the tank, a check valve and additional water pump is required.

# Hydro/Growbed

This teaches how to construct an external hydroponic growbed.

## Pipe or gutter as a growbed

Using pvc pipe as a growbed can easily become expensive, and it contains less space than a bin for growing plants.

# Passive/Bottle

A bottle or jar filled halfway with a combination of substrate material will function as a passive hydroponic system. In this setup, a bottle garden can serve the purpose of a passive hydroponic system. Certain combinations of substrates (expanded clay pellets, growstones, soilless mix, parboiled rice hulls) will wick water above water-level while maintaining aeration. Too much water retaining material (such as rockwool, cloth, or a sponge) will promote root rot, while other materials (expanded clay rocks, parboiled rice hulls, synthetic fibers) alone may not wick water high enough. It is important that most of the roots stay above water-level, unless this plant is semi-aquatic. Paint (use nontoxic) the bottom half of the container to reduce light around the plant's root-zone.
For a passive hydroponic garden, a bottle works better as it allows water to condense, keeping roots moist. Porous aggregate and condensation are enough to water plants' roots, so no further wicking material is needed in a passive hydroponic bottle garden. Unless this is a glass container, a valve drain may help rid of excess salts. When necessary, drain the water, partially at a time, by placing this valve halfway between the substrate level and the bottom of the container.

# Passive/Orchid

Passive hydroponics is one of many methods to grow plants without soil. Growing medium is inert and wicking. It delivers water with fertilizer to the roots by means of capillary action. Substrate contains many small air pockets and can thus deliver oxygen to the roots. The method has been applied to orchids.

## Container

Orchids can be planted in any non glass container. The 3-4 drainage holes are placed not at the bottom but 3-5 cm up, at the sides of the pot. The idea is to provide a water reservoir at the bottom of the container from which the medium wicks moisture to the roots.

## Popular media

LECA (Lightweight Expanded Clay Aggregate) - expanded / fired clay pellets or clay pebbles , perlite, vermiculite, diatomaceous earth, gravel, charcoal, rockwool, coconut husk chips and their combinations.

## Water

Substrate is flushed with tepid water solution when reservoir is nearly empty. Translucent pot may help to see when it is.

## Fertilizer

Orchids are fertilized with 1/2 to 1/4 of recommended strength of balanced inorganic fertilizer with every
watering. Container is flushed with plain water every month to prevent harmful salt build up.

## Conversion from conventional culture to passive hydroponics

* New medium is washed and then soaked overnight. The plant is then removed from the old pot and substrate is removed from the roots. Rotten or overlong roots are cut / trimmed away. All the roots are thoroughly washed with lukewarm water.
* Some new medium is placed at the bottom of the new container. The plant is accommodated and more new medium is put around. The pot is gently shaken, more medium is put in, more shaking and so on. Container is flushed with tepid water. The orchid is placed in the shade without fertilizing the following month.

## Which orchids can be grown?

Most popular orchids will more or less thrive in hydroponic culture: Paphiopedilum, Phragmipedium, Masdevallia, Phalaenopsis, Cattleya, Cymbidium, Oncidium, Dendrobiums, Epidendrums, Miltoniopsis, Pleurothallid and Zygopetalum.
* Exceptions would be very big or "thirsty" plants or those whose roots must sometimes completely dry and even those that require dry rest like Dendrobium nobile.

## Advantages of Passive Hydroponics

Its simplicity and effectiveness. No guessing about watering and fertilizing, no media decomposition, practically no root rot, healthy plants, fine blooming, no moving parts, low cost, reusable media.
* In hot and dry environments passive hydroponics is beneficial since the roots stay in a high humidity chamber with some air flow.

## Disadvantages

* The main disadvantage is sometimes need of more frequent watering, especially when plants begin to fill their pots, are big or otherwise demand lots of water. Obviously, a bigger pot / reservoir may help.
* If the translucent container receive enough light then algae will grow on the outer layer of the potting media. This is mainly an aesthetic concern and not a big problem indoors.
* If the medium consists of expanded clay pebbles and the plant is newly established then tipping it over may cause the spilling of the medium and plant.
* Build up of salts from fertilizer and water are not easily removed from clay substrate. Also, excess of chemicals used for pest or disease control is retained.

# Biofilter/Passive

For a passive biofilter to work, aerobic conditions must be met for beneficial bacteria. The concept is to provide a medium for beneficial bacteria to grow in aerobic conditions. Here are numerous nonmechanical subsystem and passive biofilter projects:

## Netpot biofilter

Put a synthetic screen or scrub pad over a net pot, and this cannot be a material that holds much water or that is easily decomposable. Fill it with sand, gravel, ceramic material, charcoal or any porous substrate of choice, while pushing it inside the net pot. Sand helps remove small particles. This works to remove small particles if water passes from the top.

## Ground layer biofilter

Gravel in the bottom of the tank will assist with biofiltration. It will help clear up the water.

## Aquaponic symbiosis

Plants and microorganisms remove fish byproduct waste that is dangerous to aquatic animals. Fish provide properly balanced nutrients necessary for plant growth. Different types of aerobic bacteria complete the symbiotic cycle by providing the proper nutrient fixations and reduction of toxins.