The Best Hydroponics Book, Volume 1

Index

Chapter # Title

1 Hydroponics Introduction!

2 Salinity!

3 Computer Automation!

4 Fertilize Me Baby!

5 Lighten Up!

6 p-What?!

7 CO2!

8 SupercalifragilisticexpiAeroponics!

9 Helllooooooo Poly!

10 P.B.!

11 Electronic Ultrasonic Aeroponic Fogarific Hydroponics Nutrient Delivery System!

12 Spigots!

13 Oxygen!

14 Nutrient Cycling!

15 Bio-Filters for Fish-Pee!

16 Silicon!

17 Fungus-Gnats!

18 Spider-Mites!

19 Whitflies!

20 Cloning Clinique pt. 1!

21 Intro. 2 Organic Hydroponics pt. 1!

22 Hydroponic Jalepenos!

23 Organic Plastic!

24 Hydroponic Lettuce!

25 Hydroponics Gardening on a Gradient!

26 Pearlite! Perlite! Rah! Rah! Rah!

27 Yardoponics!

28 Gravimetric Cost-Reduced Redundancy-Optimized Hydroponics!

29 Evapo-transpiration Control in Hydroponics!

30 Hydroponics Zonimetrical Gardening!

31 Hydroponics Viruses, Bacteria, and Fungi!

32 Hydroponics Plastics!

33 Back 2 Basics!

34 Back 2 Basics Part Deux!

35 Back 2 Basics Part Três!

36 Back 2 Basics Part Vier!

37 Back 2 Basics Part V!

38 Back 2 Basics Part Seks!

39 Back 2 Basics Part 7!



List of Acronyms:

Term Acronym

Controlled Environment Agriculture CEA

Electro-conductivity EC

High Pressure Sodium HPS

Metal Halide MH

Light Emitting Diode LED

National Aeronautics and Space Administration NASA

Photosynthetically Active Radiation PAR

Power of Hydrogen pH

Polypropylene PP

Electrostatic-dissipative ESD

Polystyrene PS

Polyethylene PE

High-Density HDPE

Low-Density LDPE

Photosynthetic Photon Flux Density PPFD

Transistor-Transistor-Logic TTL

Glossary of Terms:

Term Class Feature

Aeroponics Plant growth method Allows media-less culture

ex. Aeroponics is a plant culture technique whereby plants are fed by having a nutrient solution sprayed onto their bare roots.

Bio-reactor Bio-mechanical device Turns waste into plant food

ex. A bio-reactor can turn plant and human waste into plant food.

Electro-conductivity Measurement criteria Shows nutrient concentration

ex. The electro-conductivity of pure water is nearly zero, but it rises as fertilizers or other ionic compounds are added into solution.

Flywheel Mechanical device Stores electricity

ex. A flywheel can be used to store electrical energy supplied by solar arrays as kinetic energy in a magnetic mass spinning inside a conductive case.

Hydroponics Plant growth method Maximizes oxygen supply

ex. Hydroponics is a method of growing plants in soil-less media or directly in nutrient solution.

Photosynthetically

Active Radiation Energy form Facilitates photosynthesis

ex. Photosynthetically Active Radiation is the radiant energy required by plants to photosynthesize.

Transpiration Plant function Moves water

ex. Transpiration is the process where plants take up water and then give it off as a vapour, it is comparable to mammals’ perspiration.

Xerohyte(ic) Plant/Biome type Drought tolerant or dry

ex. Xerophytic plants like Cacti can thrive in arid, desert like habitats.

Chapter #1: Hydroponics Introduction!

Hydroponics is the water-based growth of plants, usually directly in water or in soil-less mix, although there are many variations. Because of the ability to have control over water and nutrient solution management as well as increasing oxygen levels in the root zone, crop productivity can be increased significantly when compared to regular outdoor growing methods.

Many people immediately picture some high-tech apparatus used only by NASA Engineers or University students when they hear the word Hydroponics, but the truth is that Hydroponics culture methods have been successfully used to grow ornamental and edible crops for millennia. One of the first documented Hydroponic gardens was the famed Hanging Gardens of Babylon in Iraq @ http://pharos.bu.edu/Egypt/Wonders/gardens.html . Mother Nature has also been busy using Hydroponics anywhere that plants grow in sand, gravel, etc..

Hydroponics methods are now widely employed around the world, especially in Temperate regions where greenhouses can be operated year round without the need for supplemental heating. Many different crops are grown including Strawberries, Cucumbers, Lettuce, Tomatoes and Orchids. Virtually any plant can be grown Hydroponically as long as the specific water and nutrient consumption rates of that plant are taken into account.

There are a myriad of different techniques used, with the Wick, Nutrient Film Technique(NFT), Floating Raft, Drip, and Ebb & Flow methods being the most prevalent. Aeroponics is a new twist that is basically a method of feeding the plants by misting the roots with nutrient solution.

The Wick method consists of having pots or a tray full of media with plants in it above a reservoir of fertilizer solution with wicks transferring the solution to the plants through capillary action. This is the most basic system, but works well.



The NFT system works by having troughs or pipes which the plants are kept in with a steady stream of nutrient solution pumped through. The solution level is kept at a thin film to maximize the oxygen available to the plants roots.



The Floating Raft technique consists of growing the plants on floating Styrofoam rafts on an aerated nutrient solution. This system is best suited to growing lettuce and other small leafy plants that don't require much support.



An excellent link for the Floating Raft method is http://www.cals.cornell.edu/dept/flori/let...tuce/index.html that is the CEA hydroponics site at Cornell University.

The Drip method works be having the plants in pots or trays and the solution is supplied by pipes and dripped onto the roots.



The Ebb & Flow system works by having the plants kept in a raised tray into which the nutrient solution is pumped and then drained.

The management of the nutrient solution is of great importance when growing plants Hydroponically. Most growers mix there nutrient solution from commercial grade powdered mixes or from raw chemicals and top up the solution until imbalances occur. These imbalances occur because there are certain nutrients present in most water supplies which can build up to toxic levels in the solution after time due to the fact that the plants don't use them such as Sodium and Chlorine. Some facilities use Re-circulating solutions to minimize waste fertilizer being dumped and they are usually forced to use pure, filtered water to avoid the toxic build-up problem.

The pH value of the solution, which is a measure of the acidity or alkalinity, must also be monitored to keep the plants growing at optimum levels. The pH can be adjusted by adding acids or bases as required.

There is a vast array of different growing substrates available today, with Perlite, Vermiculite, Peat Moss, Coconut Husks(Coir), Sand, Gravel, polyurethane blocks and Rockwool being some of the most popular. Recently, Perlite has become the favourite of many commercial and hobby growers, with Rockwool also being popular, but it requires pH adjustments due to its Alkalinity. I hope this chapter has given you a good basic introduction to Hydroponics and you should visit the list of links to Hydroponics related sites at http://www.Suite101.com for more information.

Chapter #2: Salinity!

One major hurdle facing growers who wish to re-circulate their hydroponic nutrient solution in order to reduce waste is the build-up of toxic salts over time. This problem has also caused the destruction of large amounts of surface soils in arid and semi-arid countries around the world.

The most common problem salts in water supplies are; chlorides and sulfates of calcium, magnesium, sodium, and potassium (Bray, 1990). These salts accumulate because insufficient rain falls to purge them from the soil. They can be removed through leaching or conversion with Gypsum and/or Sulfur and Sulphuric acid, and evaporation control (Bray, 1990). Reverse-osmosis water filtration units can also be used for nutrient top-up. Alternatives include precipitation and removal with activated charcoal.

Canadian researchers at the University of Toronto have made a breakthrough discovery that could help to reclaim vast amounts of farmland. They have apparently successfully transformed normal plants into plants that will accumulate a much larger Sodium load than usual. Go to http://www.cbcnews.cbc.ca/cgi-bin/template.../farmsoil990819 for more information.

References: Brady, Nyle C.. The Nature and Properties of Soils. New York, New York. Macmillan Publishing Company: 1990.


Chapter #3: Computer Automation!

This chapter focuses on various methods and technologies involved with Hydroponics system automation.

The usual variables which are controlled through automation are light and watering cycles, Electro-Conductivity (EC) which relates to nutrient concentration in solution, pH (acidity/alkalinity which will be discussed in detail in a future article) of the solution, and atmospheric temperature and humidity.

The control of light and watering cycles is easily achieved through the use of timers that can be bought at the local hardware store. Relays can be used where switching high currents is required for lots of lights. For automation freaks, computer systems are available from http://www.x10.com and http://www.honeywell.com which can be used to control lights, pumps, etc..

The EC of the solution is best monitored using an electronic meter which measures the conductivity of the solution which rises according to concentration of ions and the units are micro-Siemens per centimeter (uS/cm). These can be purchased from many companies like http://www.hannainst.com . These meters cannot actually measure the nutrient parts per million (ppm) because of the varying solubility to conductivity ratios of different substances, but some are calibrated to convert from EC to ppm according to the assumption that ~2uS/cm=1ppm. Computer automation for EC control can be achieved using simple software to control a probe wired through an analogue to digital converter (A/D) and into a computer or micro-controller which can then turn on a pump to add more nutrients when required. A/D chips can be bought for ~$2 from http://www.jameco.com or http://www.dalsemi.com or http://www.microchip.com .

The pH of the solution can also be monitored using electronic devices, but it has been our experience that it is more efficient to use pH indicating kits which contain Bromthymol Blue or other substances which react to turn certain colours for different pH values. These kits can be purchased in pet/aquarium/superstores. The electronic pH meters work OK, but the glass electrodes corrode naturally as they work, and have to be replaced. Proper media should be selected to reduce the possibility of pH fluctuations. This is one reason why many other growers choose to use Perlite (Pearlite) and other substances rather than Rockwool due to the fact that Perlite is pH neutral, whereas Rockwool is alkaline in nature and usually requires acid treatment.

Temperature and humidity are easily controlled using thermostats and de-humidistats connected to exhaust fans.

There are very complex computer modelling software packages being developed which will be able to predict the amounts of nutrients required by crops in re-circulating systems according to environmental conditions, but these programs are in their infancy, one prototype can be found at http://res.agr.ca/harrow/software/software.htm .


Chapter #4: Fertilize Me Baby!

Plants grown Hydroponically must have all of their required nutrients supplied in the fertilizer nutrient solution rather than obtaining them from the soil like traditional crops in the field. This allows for greater control of the growing environment, but can also lead to deficiencies if all the required elements are not in the solution.

Many studies have been done by plant physiologists over the years to determine the concentrations of nutrients that plants require and a recognised authority in this field is Dennis R. Hoagland who developed the "Hoagland's solution" which is a benchmark for optimal plant growth and is used all over the world.

The essential micro- and macro-nutrients which all plants require and their tissue concentrations for optimum growth are:

Macro-nutrients(%):

Sulfur 30

Phosphorus 60

Magnesium 80

Calcium 125

Potassium 250

Nitrogen 1000

Oxygen 30000

Carbon 40000

Hydrogen 60000

Micro-nutrients(ppm):

Molybdenum 0.001

Copper 0.10

Zinc 0.30

Manganese 1.0

Iron 2.0

Boron 2.0

Chlorine 3.0

(Taiz & Zeiger, 1991)

Certain plants such as rice also require Silicon for proper growth.

One problem with growing plants in Hydroponics nutrient solutions is Iron deficiency that can occur due to the Iron precipitating (coming out of solution as a solid) into insoluble Iron Hydroxide. Modern fertilizers use chelating agents such as ethylenediaminetetraacetic acid (EDTA) which keep the iron and other trace elements in solution. Precipitation of other substances such as Calcium Phosphate can occur if concentrated nutrient solutions are prepared, so solutions are best prepared separately prior to dilution and use, usually in 2-part "A" & "B" solutions.

Most commercial Hydroponics growing operations use premixed fertilizers to reduce the chances of nutrient deficiencies occurring caused by human error and to reduce the labour involved in ordering and preparing nutrient solutions from scratch. Various recipes used for lettuce, tomatoes, and cucumbers can be found at : http://www.cals.cornell.edu/dept/flori/let...tuce/stock.html

http://www.usu.edu/~cpl/nutrwht.html

http://res.agr.ca/harrow/bk2/cuke1a.htm

http://res.agr.ca/harrow/bk/tomch9.htm

http://www.ag.arizona.edu/hydroponictomato...es/nutritio.htm

http://members.tripod.com/Client_Profile/l_form.htm

http://www.biotron.slu.se/bio3375.htm

http://edis.ifas.ufl.edu/scripts/htmlgen.e...?DOCUMENT_VH030

http://www.np.edu.sg/~dept-bio/sssc/nutr.html

http://www.hbci.com/~wenonah/hydro/nitragen.htm

http://www.atlantic.net/~elifritz/hydroponics.htm

http://nfrec-sv.ifas.ufl.edu/nutrient_solution.htm

Another good source for recipes is the Journal of Plant Nutrition, esp. Vol. #21. Issue #10 which compares 12 different solutions.

Also, check out

http://www.hydromall.com/info/eleccon.html

for values.

The units of measuring fertilizer solution concentration are Siemens and Mhos where 2 microSiemen(uS)=2 micromho(umho)=~1 ppm(approximation). Siemens and Mhos are units of Electrical Conductivity (EC) as described in an earlier article and are reciprocals of resistance (Ohms) as the EC of solutions increases linearly with nutrient concentration. Typical nutrient concentrations are from 1000-3000 uS/cm (~500-1500 ppm) depending on size, type of, and growth rate of the plants.

You can prepare your own calibration solution by calculating using the equation C=Q/V where C=concentration desired, Q=quantity of solute, and V=volume where 1g/L=1000ppm.

References: Taiz & Zeiger. Plant Physiology. Redwood City, California. The Benjamin/Cummings Publishing Company: 1991.


Chapter #5: Lighten Up!

Plants have evolved over many eons through natural selection (except maybe in Kansas) to use the energy available to them in Sunlight as efficiently as possible. This part of the spectrum which plants use is defined as Photosynthetically Active Radiation(PAR). PAR light output is usually expressed in units of micro-moles(umol) or micro-Einsteins(uE)of quanta per Watt(W) and measured in umol or uE per square metre per second ((umol*m-2)*s-1 ((umol/m2)/s) or (uE*m-2)*s-1 ((uE/m2)/s)) of Photosynthetic Photon Flux Density(PPFD).

Human eyes have developed to utilize different wavelengths for vision as seen in the (rough) graph which shows the relationship between the daylight spectrum that reaches the Earth and the wavelengths used by plants and humans. As you can see, plants only use certain wavelengths of the electromagnetic spectrum, peaking in the blue and red regions, while the human eye can best see light in the yellow area, with the "Lumen" being used to relate the amount of light put out by bulbs that the human eye can see.



Supplemental lighting is required in greenhouses and grow-rooms when insufficient daylight is available. The artificial light source of choice must have an output that will match, as closely as possible, the spectrum plants required for photosynthesis. While the amount of Lumens put out by bulbs can give a rough estimate of which bulb to use, PAR ratings are more useful when choosing lights for plants and conversion factors are available to convert from Lumens to PAR ratings for most light sources. Metal Halide (MH) and High Pressure Sodium (HPS) lamps put out about 14 umol PAR per klux, White fluorescent give ~12 and Incandescent give ~20, but HPS can give up to 120-140 klumens per 1000 Watts while MH give only 80-100, Fluorescent give ~70 and Incandescent give only ~20. "Gro" bulbs put out slightly more. Compact fluorescent bulbs can put out close to ~3000 lumens @ 40 watts. Halogen bulbs can also be useful because of ease of implementation. Greenhouses and also many university Phytotrons use various types and combinations of bulbs.

When no daylight is available at all (i.e. indoors), some supplemental MH and fluorescent lighting is usually used because the HPS lamps put out a reddish spectrum which can lead to plants getting "leggy" (spindly) if some additional blue light isn't added.

The accepted value for optimal growth of lettuce & spinach is 200-300 umol*m-2*s-1 PAR PPFD, so a 1000W HPS system putting out 140 klumens @ 14 umol*m-2*s-1/klux will give 1960 umol*m-2*s-1 which divided by 250 for good illumination & optimal growth gives 7.8 square meters or ~70 square feet maximum for each unit (Roughly), for a more accurate calculation using Illumination Engineering Society guidelines for calculations involving Room Surface Dirt Depreciation, Lamp Lumen Depreciation, etc. please download our calculator from:

http://hydroponics.hypermart.net/light.exe

The recommended level for tomatoes and cucumbers is ~100 umol*m-2*s-1 and listings for other plants can be found in the Illumination Engineering Handbook in most libraries (footcandles * 10.7 =lux and lux * 0.93=f.c.).

Check out:http://www.animalnetwork.com/fish2/aqfm/1998/nov/features/1/default.aspandhttp://www.biocontrols.com/aero65.htmfor more info..

Chapter #6: p What ?!


As alluded to earlier, the pH of hydroponic solutions is an important factor to regulate for optimal plant growth. The term pH comes from the French "pouvoir hydrogen", meaning the "power of hydrogen". Pure water has a pH of 7.0 and acidic solutions have more free hydrogen atoms and a lower pH (<7) and basic or alkaline solutions have a higher pH (>7) and less free hydrogen atoms (Bailar, et. al., 1989).

In hydroponics, the pH value has a greater significance with respect to nutrient availability than in regards to cellular damage which can be inflicted by extremely acidic (pH=<4) or basic (pH=>9) nutrient solutions. This is because molecules of nitrogen, sulfur, etc. become insoluble at lower pH values and at higher pH’s, ions such as iron, copper, and phosphorus can precipitate out of solution. Therefore, proper solution pH must be maintained to ensure proper plant growth.

As mentioned in my previous article, the best way to check the solution pH is to periodically ( 1ce a day or so) check it using a cheap pH test kit. The more expensive meters work, but are unnecessary as rapid pH fluctuations should not occur, and if they do, you likely have some other problem such as supplying nitrogen as nitrate (NO3) alone, rather than applying it in combination with ammonium (NH4) which will help to eliminate quick rises in the pH (Taiz & Zeiger, 1991).

As the plants remove nutrients from the solution, the pH will naturally rise slowly and become more alkaline, which must be counteracted with acids; nitric, phosphoric and sulfuric being the most common used. In contrast, if solution acidity is a problem (which happens rarely) potassium or calcium hydroxide can be added, or lime added to the growing medium will often help and is good practice to buffer pH fluctuations.

Different plant species have been experimentally shown to grow best in different pH ranges, with acid loving plants such as Azaleas, Rhododendron and Cranberries growing best in the pH 4-5 range. Plants such as Soybeans, Tomatoes, Cowpeas, Cucumbers, etc. prefer to be grown in solutions with an optimum pH of 6.0 and other plants such as Lettuce, Cabbage, Carrots, etc. prefer a slightly higher pH of 5.5-8 (Brady, 1990). As a general rule, a pH of 5.7-6.0 is best for most food crops.

Check outhttp://www.hydromall.com/info/eleccon.htmlfor data.

p.s. According to differential solubilities, most plant nutrient ions are most readily available in solution from ~pH 5.5-8 depending. They can precipitate out of solution or become bound outside of this range causing the TDS to drop. Fertilizers are also usually acidic and will lower the pH when added along with raising the TDS. When plants selectively deplete ions from the solution lowering the TDS, the pH will usually rise accordingly.

References:

Bailar, et. al.. Chemistry. Orlando, Florida. Harcourt Brace Jovanovich, Inc.: 1989.

Brady, Nyle C.. The Nature and Properties of Soils. New York, New York. Macmillan Publishing Company: 1990.

Taiz & Zeiger. Plant Physiology. Redwood City, California. The Benjamin/Cummings Publishing Company: 1991.


Chapter #7: CO2!

This chapter is about carbon dioxide (CO2) fertilization. Plants require CO2 to use in the photosynthetic cycle where it and water vapour chemically combine producing carbohydrates (sugars) for energy, and releasing Oxygen and excess water vapour.

CO2 becomes a limiting factor for growth when sufficient light, water and fertilizer levels are available as the CO2 is depleted by the plants and must be replaced by venting or supplementation. The atmospheric concentration of CO2 is ~0.035% (~350 parts per million (ppm)), and plants have been shown to have up to a 200% increase in growth at 700 ppm (Taiz & Zeiger, 1991). The accepted value for maximum growth of most crop plants is 1500 ppm CO2. CO2 levels should not be increased in areas where humans and/or other animals could be exposed, without all proper safety precautions being implemented.

CO2 can be supplied by various means, including injection from compressed tanks of liquid gas, production via combustion, fermentation, chemical reaction and catalytic combination. Tanks of compressed gas and combustion are the two most common methods for CO2 fertilization, with combustion being mainly used in outdoor greenhouses in cooler climates where excess heat can be used. The fermentation method using brewer's yeast can be applied to small grow-rooms, but is messy and smelly, but cheap and effective.

The control of the levels of CO2 available for assimilation in the growing area can be a problem. The amount of fuel required to burn to achieve a desired CO2 level is predictable using molecular weight calculations, but most commercial production units are calibrated and come with timing sheets for the production rates. When using fermentation, it is nearly impossible to predict the exact amount that will be produced and CO2 monitors are recommended, but are currently quite expensive. It is easiest to use compressed tanks of the gas that can be used with flow-meters or gages that are calibrated accordingly, usually in cubic feet per hour (CFH) which can give you a rough estimate of the levels. Using calibrated monitors are the most effective means to determine the CO2 levels.

There is currently anecdotal speculation that addition of Lecithin (Soy?) to the root zone can facilitate CO2 uptake by the roots and studies are ongoing.

References: Taiz & Zeiger. Plant Physiology. Redwood City, California. The Benjamin/Cummings Publishing Company: 1991.


Chapter #8: SupercalifragilisticexpiAeroponics!

This chapter will give you a description of how to build your own cheap and very effective aeroponic "cloning" chamber to use for quick rooting of cuttings. We came up with this design a few years ago and it is incredibly simple and efficient and can be completed with a few parts from your local hardware/pet/Borg store. We will not add a picture (because we won't have our digital camera until Christmas), so you will have to use your imagination.

The parts you will need are:

-Rubbermaid™ or other suitable plastic orr plastic-lined wood box or aquarium

-water pump (~>200GPH), preferably maggnet driven & fish-safe (those are usually corrosion proof and made to run continuously)

-some plastic sheet (preferably white)
-Exacto™ knife

-misting, nebulizing, vaporizing (vapouriizing), or atomizing head(s) from the lawn-sprinkler/garden department of the store (try to get them in full circle 360 degree coverage) you could also order on-line @:

http://www.truefog.com/catalog.html

http://www.kesmist.com/homepage.htm

http://www.raindrip.com

or you can use an ultrasonic fogger mister when they are readily available

-some poly pipe & fittings

Firstly take the lid of the container & cut some dime-sized holes in it, approximately 3-6 inches apart. Then attach your misting nozzle to the pump on a 5-10 inch riser (piece of poly pipe) and place it in the bottom of the container and add enough water to cover the pump + a few inches extra so it doesn't run dry and test the nozzle to see what kind of spray pattern you get. There is a myriad of misting nozzles available around the world, so the toughest part of this endeavour will be to fit the nozzle(s) to your pump so you get a good mist going in the container. You may have to use a couple of heads & couplings & T's & nipples, but everything will be available in the plumbing section of the store. Today I went to a local hardware store (which shall remain nameless) and purchased a head for 98 cents and it worked well enough when attached to my 250 GPH pump to fill my box(10 gallon) with mist, I was lucky.



When you get the pump & misting head(s) set up, you are done. Add water and maybe 1/5th of a multivitamin (dissolve the vitamin in a jar of water first & strain it into the box so you won't clog the mister head with chunks), put the lid on with the piece of white plastic on top which now has slits cut in it to poke the cuttings in through the holes, insert your cuttings, put the pump on a timer to be on whenever light is supplied or in intervals & you're off. Your cuttings should root in 1-3 weeks, depending on the species. This technique won't work for all plants, but you can test a few from around the house & garden, & some will love it.


Chapter #9: Helllooooooo Poly!

Polystyrene (PS), High-Density Polyethylene (HDPE), Low-Density Polyethylene (LDPE), PolyPropylene (PP), Polyethylene Terephthalate (PET), Mylar, Nylon (PA), etc., etc.. These are a few of the labels you will find around the house on polymer food containers. When it comes to building a hydroponics system using polymer containers, you should use some of these same products. Rubbermaid™ for example have assured us that their products are safe to use for hydroponics systems. If you are building a large tray system to be lined with poly. sheeting, you should not use something like mildew resistant construction vapour-barrier as it may be phytotoxic (harmful to plants) due to being impregnated with pesticides. Instead, you should contact local plastic wholesalers or farm supply companies and tell them what you want. You can also check out AT Plastics (who manufacture agricultural food and hydroponics-safe polymers) at http://www.atplastics.com or other plastics manufacturers and find a local distributor in your area.

There have been a few studies done lately which warn of plasticizers that can be released from certain poly. products into foods, such as DEHA in plastic wraps. One link for information concerning this is http://www.plasticsinfo.org/food/index.html and certain scientists have stated that soft plastics, like the Poly-Vinyl Chloride (PVC) should be avoided as they may release additives into the surroundings.

There have been rumours that recycled plastics may contain high levels of Lead &/or other toxins.

It has also been stated that "...components that come in contact with the nutrient solution, as many as possible should be made of plastic because metal can release potentially toxic levels of certain micro-nutrients such as zinc and copper in the solution. Because of the widespread use of plastics, take care to select materials that are not phyto-toxicity. As a general recommendation, PVC and low- and high-density polyethylene or polypropylene are acceptable, but plasticized PVC used in the manufacture of flexible hose, or butyl rubber sheet lining, used for waterproofing reservoirs, should not be used in NFT as they may be phyto-toxic. Plastics are more likely to cause phyto-toxicity when they are new. Plastic surfaces quickly lose their potential phyto-toxicity when exposed to nutrient solution. Therefore, before planting a crop, flush out the new hydroponic installation entirely for 1 day with a dilute nutrient solution that is discarded." by Dr. A. P. Papadopoulos "Growing greenhouse tomatoes in soil and in soilless media" http://res.agr.ca/harrow/bk2/cuke-toc.htm

A couple of other interesting links can be found at http://www.plasticsinfo.org/food/packaging.html and http://www.cfia-acia.agr.ca/reference/q1-c.html#C .


Chapter #10: P.B.!

The Perlite Bed Theory:

Perlite (a.k.a. Pearlite) Beds and their variations have to be some of the most versatile and simplistic yet productive hydroponics systems ever conceived. Perlite Beds can be adapted to grow plants in many configurations including ebb-&-flo, NFT, flood-&-drain, dripper-matrix, soaker-hose, pipe-action, etc..

Complete Perlite Bed units can be easily designed and built to fit any space. A large poly. tray or poly. lined wooden tray arrangement with a thru-hull fitting to a poly. or other reservoir beneath forms the basis for each unit's functionality. The nutrient solution is pumped up to the plants on top and flows back into the reservoir where it is controlled & monitored.

For larger spaces, many units can be used in unison. Each unit then serves as a modulus creating a modular expansion capability.

Perlite used alone or in combination along with other amendments such as Vermiculite, Rockwool, Dolomitic Limestone, Peat Moss, etc. is the medium used to form the substrate to support the plants roots. Combinations can be mixed to allow creation of "Zones" suitable for optimized plant growth. Perlite is cheap and easily obtained at any farm-supply or gardening nursery store for ~$10-20/110L. The media can also be bagged.

Fish-pumps and other types can be used. Magnetic-driven seem to be the most efficient and trustworthy available.

The beds can be built on top of tables, sawhorses, or other support apparatus. Minimal pH adjustment should be required with a Perlite Bed and evapo-transpiration rates can be controlled using modified substrate recipes and/or addition of landscape fabric or poly. sheeting or other mulches to the medium's surface.

The bed(s) should be rinsed regularly with clean water to avoid nutrient level fluctuations.


Chapter #11: Electronic Ultrasonic Aeroponic Fogarific Nutrient Delivery


There is a revolutionary new product available on the market that uses electronic vibrators to transform ordinary liquid water into sub-micro evaporative fog mist droplets that can be used to feed and humidify plants.

These units consist of electronic transducers that are pieces of crystals (piezo) that vibrate according to the degree of electrical current supplied and can be driven to such a rate that they emit ultrasonic "beams". If they are squeezed or vibrated, they can also release electrical current.

The micronic size of the atomized droplets allows for deep penetration of growing chambers and optimal availability to the roots. The "fog" created is equivalent to the white, puffy clouds floating in the sky. The endothermic evaporative reaction producing the fog can cause the temperature to drop, but subsequent exothermic condensation will make it rise so the temperature must be monitored and a heater may be necessary.

Nutrients and amendments can be added to the solution as required for delivery to the plants’ roots. Possibilities include using the units for root or foliar treatment combinations.

Pulsing timed oscillating excitation is recommended to extend the unit's useful life as prolonged vibration may cause degredation.

There are many sources for purchasing the technology, we will be posting the most economically efficient manufacturers soon in the list of Hydroponics links.

Chapter #12: Spigots!

Spigots can be very useful when designing a Hydroponics or Aeroponics system as they allow for ease of nutrient solution monitoring and cyclic renewal.

On the other hand, they can be a cause for concern when they leak. Care should be taken when shopping for suitable spigots to allow for quality assurance. Nothing can be more annoying than a leaky spigot.

Some people frown upon spigot-usage and prefer to practice spigot elimination in the quest for dryness and leak-proofedness. Spigot avoidance can be achieved through the use of a siphon-hose, pumps, dumping, overflow utilization, etc.. However, certain cases require spigot usage and we recommend you rely upon heavy-duty spigots bought from hardware, plastic, wine, or industrial supply stores.

Both metal and polymer spigots are available, with stainless-steel and non-recycled food-safe plastics being the most desirable construction materials to allow for preventative solution contamination elimination.

Teflon©™® tape can come in very handy when trying to prevent leakage occurrence, as can food-safe silicone products.

Plastic filters can be used when the spigot is to be placed in a tray of loose media to prevent losses.

Spigots can be attained that have different modes of operation and features. Some have a pressure-operated lever system to open, while others have a mechanized valve that must be opened and closed by turning the knob on the shaft. Yet others have push-button opening.

An interesting couple of links are located @:

http://www.securefuture.com/water2.html

http://www.polyflow.com.au/

Chapter #13: Oxygen!

One of the main benefits of growing plants using hydroponic and aeroponic techniques is the maximization of oxygen in the root zone. This abundance of rhizobial (root zone) oxygen allows for optimized root cell respiration and maximized plant growth.

Conversely, in compacted soils or stagnant pooled nutrient solutions, oxygen levels can be depleted to a point where cellular damage occurs in the roots which subsequently leads to shoot growth retardation. This depletion is caused both by the plants themselves, as well as naturally occurring bacteria using the available oxygen faster than it can be replenished through diffusion from the atmosphere above the soil or substrate surface.

Low-oxygen (anaerobic) soils also allow for the growth of detrimental bacteria which can deplete mineral nutrients such as nitrogen an sulfur, which can ultimately lead to deficiencies and further extend crop losses.

Oxygen concentration maximization is the basis for the Nutrient Film Technique (NFT) which uses a thin film of nutrient solution to feed the plants and the nutrient film must be thin enough to allow for easy oxygenation. The use of perlite (pearlite) and other substrates also allow for increased oxygenation, but this gain in production can many times be counteracted by practices such as wrapping blocks of media in plastic liner, or placing plastic "mulch" over the substrate in order to reduce evapo- transpiration. Oxygen levels can be increased in the nutrient solution be using aeration devices like "air-stones" and pumps commonly used in fish tanks.

Water and oxygen management is a discrete science with a balance being achievable between crop production and water usage. Where water consumption is not an issue, oxygenation should be increased through the use of porous, aerating substrates. When evapo-transpiration reduction is necessary, plastic mulch may be used more efficiently by cutting holes in the material around plant stems to allow oxygen to feed the roots, and transpiration-reducing wax emulsions may also be applied to the plants' leaves and stems in moderation.

It has been scientifically proven that oxygen reduction in the shoot zone can actually increase dry mass production, but due to associated root zone depletion in normal practice, this is not a viable practice.


Chapter #14: Nutrient Cycling!

Some "people" practice "open-ended" cycling routine agendas while others are constantly striving to improve their "closed" or "batch" culture schemes.

In a perfect world a closed system could function indefinitely. You would apply nutrients, light, CO2, & water to the system and get plants out without any waste being produced. In reality, the system will likely develop an imbalance and require that corrective measures be applied. Where water conservation and pollution reduction are necessary &/or possible, & where secondary ion depletion can be imposed on nutrient effluent, consumption can be facilitated in an environmentally symbiotic fashion.

Depending on circumstances allowances, nutrient solutions may be continuously utilized by re-circulating the same batch indefinitely on crop plants until refreshing is necessary when the old batch is optimally "filtered" through ornamental or other crops to minimize secondary environmental impact, or fresh mixtures of the solution are applied to the plants during subsequent fertilizer application with any effluent being used as described above.

Reverse osmosis filters and other types of water purification systems allow for emergency or routine water management control. This control can vastly elongate nutrient replenishment deferral times and reduce water requirements.

Tissue and fertilizer solution sampling are commonly used to perfect nutrient application recipës.

Certain regimes have been applied successfully where nutrients are applied in a one-way-street fashion where all moisture applied is to be processed by the plants without allowing for re-circulaition or expulsion, but these routines can be difficult to manage as evapo-transpiration rates are often difficult to foresee or predict in unison with nutrient level maintenance. Nutrient deficiencies &/or toxicity symptoms are risks which can be managed.

Chapter #15: Bio-Filters for Fish-Pee!

Fishes excrete a higher concentration in parts-per-million (ppm (mg/L H2O)) of waste in the form of the Ammonium (NH4+) ion in solution in equilibrium with water than mammals because of the fact that their hypertonic tissues can readily receive water when required by diffusion (osmosis) from the surrounding liquid body.

In ponds, aquaria, and other biospheres which can loosely be considered isolated "batch" or "closed" culture systems, this can result in difficulties arising because ammonia is toxic to fish in high enough concentrations and must therefore be removed from the solution accordingly.

Mammals and other animals, with their limited water store & resources, utilize chemical reactions in their bodies which convert ammonia to less toxic urea which can be loaded to higher levels.

Activated carbon filters have been used for many generations when unwanted ion reduction has been required. Recently other types of filters such as "Reverse Osmosis" *("R.O.") and others have been employed.

Mother Nature has developed a system over many millennia of performing mineral cycling which allows for re-use of ions through chemical manipulation. The "Nitrogen Cycle" involves nitrogen being cyclically exchanged between animals, plants, water, the soil, and the atmosphere.

Plants can readily absorb and use Nitrogen in the form of Ammonium or Nitrate ions, and they can convert Urea into Ammonium for use to build proteins, etc..

In soil and regions where moisture levels allow, the process of breaking down toxic compounds like ammonia is achieved through oxidation by bacteria into usable substances. This process is known as "Nitrification" and is performed by the chemoautotrophic bacterium Nitrosomonas which breaks down Ammonia (NH3) to Nitrite (NO2-) (which is highly toxic to plants) and Nitrobacter which transforms Nitrite to Nitrate (NO3-) which plants can use.

"Bio-filters" are apparatuses which attempt to mimic the outdoors by creating a haven for reproduction of nitrifying bacteria. They usually consist of a supporting form, such as a large Rubbermade® or other container with gravel or sand or porous poly. or other material(s) inside in mesh bags, over which the system solution is pumped, allowing for maximum air penetration and moisture distribution. When used in conjunction with plants, toxin and nutrient levels can be reduced and managed as desired.


Chapter #16: Silicon!

Silicon has a plethora of uses in the known Universe including everything from being used in flexible, heat-resistant adhesives and sealants to forming the substrate for today’s "high-speed" computer processors.

Certain plant species such as rice also require silicon for proper growth, maturation, and reproduction.

There has been recent speculation and apparent experimental justification resulting in some "authorities" concluding that silicon is also a beneficial and in many cases essential element for optimal crop, ornamental and other plants' physiological metabolistic cycles.

In the natural environment Silicon is present abundantly in many classifications of soils such as Silicate minerals including the tetrahedral ionic crystalline sheets of clays including Vermiculite, Kaolonite, Talc, etc.. The Silicon stored in these substances is released upon weatherisation or breakdown of the compounds and made available for plants in the vicinity.

Organisms classified as "Diatoms" which are microscopic life-forms also accumulate Silicon in their cellular wall structures. These beasts manifest their existence in many aquatic environments around the world causing the accumulation of Silicon in large quantities when they die and build up on the water bodies' floors. "Diatomacious Earth" is sold in many regions and consists of the mined lifeless skeletons of these diatoms which serves to act as an insecticide because of the penetrating nature of the minuscule particles which can block insects' air passages, resulting in death.

In Hydroponic cultures, Silicon may be depleted when not supplied by external means and certain scientists have performed experiments which show that certain plants grow more vigorously when Silicon is supplied in supplemental form such as Potassium Silicate. Diatomaceous Earth and Vermiculite may also be used as organic natural sources of the mineral.

Chapter #17: Fungus Gnats!

Fungus Gnats (pronounced "Phungus Nats") (Mycetophila spp.) are disgusting, destructive insects which feed upon wet plant matter and fungal material causing huge amounts of damage to hydroponic and conventional crop plants world-wide on a daily basis.

These "bugs" are recognizable by their "fruit-fly"-like appearance: i.e. they are very small black flies which buzz and flitter around the soil/substrate/food source surface in a very annoying fashion, appearing harmless to the naked eye.

They proliferate in moist areas where food is plentiful, such as hydroponics gardens which have an abundance of plant material and fungi available for them to munch on.

I have experienced infestations when growing hydroponic garlic plants. The gnats initially appear to feed on dead plant matter and microscopic fungi, but subsequent actual living plant damage is evident, perhaps when they run out of fungal material and dead plant matter to ingest.

Remedies include accepting the little monsters as co-habitant existents (this is the method preferred by vegan wussies) or decimation by biological or chemical means. Organic Pyrethrum insecticides have been used with great success, as have been Nematodal & Spider-mital beneficial predatorily destruction techniques.

I will be adding a labelled diagram when I get my "new" computer in a couple of weeks as my old 486 is getting tired, listless, and cumbersome.

Chapter #18: Spider-Mites!

Spider-Mites (Tetranychus spp.) are parasitic pests which are arachnids and members of the Order Acarina. They occur naturally in nature throughout North America and in other regions around the world.

In cold winters, most will die off, but some eggs will survive and hatch in the Spring to renew the outdoor colonies. Others will be lucky enough to migrate into houses, barns, greenhouses and other buildings to continue growing and breeding.

Outdoors, Spider-Mites are not usually associated with large amounts of crop damage because of natural predation which controls the population. Indoors without the presence of predators, where they are able to get access to virtually unlimited food sources such as in greenhouses full of tomatoes, beans, or other plants, they can breed and form populations which can virtually obliterate thousands of dollars worth of plants. They do this by feeding on the plants using their sharp, piercing mouth parts to get access to the nutrient-rich "sap" inside leaves and stems. The damage they inflict weakens the plants to the point where they become susceptible to diseases such as viruses and bacteria.

Spider-Mites are very small, but can be recognized with the naked eye as tiny white-gray dots on the underside of leaves which appear in the presence of silky webs which harbour hundreds of eggs. Under magnification, they look like tiny, little spiders. "Two-Spotted" Spider-Mites (Tetranychus urticae) are very common and more hardy than some other varieties making them worthy adversaries. They can be differentiated from other species by the obvious black spots present on them.

Control of Spider-Mites can be arranged though the use of "organic" concoctions made up of Tobasco©® sauce, alcohol, tobacco, soaps, garlic, etc., but we have found that it is more practical and efficient to decimate the mite population using organic Pyrethrum(in/oid) sprays or insecticidal soaps as this allows for quick plant regeneration without the possibility of toxic shock occurring due to the build-up of control agents in the plants' tissues and surrounding soil. Another option is to import stealth assassin squads of predators including P. persimilis, A. fallacis, Feltiella, and Neoseilus californicus, but again, this option is not as fast-acting as the Pyrethrum spray. Pyrethrum sprays are supposed to be quite safe and non-toxic to humans, and he are reported to degrade quickly, but can also be rinsed off if desired.

Chapter #19: Whiteflies!

The greenhouse whitefly (Trialeurodes vaporiorum, Family Aleyrodidae) is a cute, fuzzy little insect which must be destroyed to prevent infestation and crop destruction!

These insects, like other greenhouse and indoor pests, exist naturally outdoors and migrate inside in colder climates to survive.

The yellowish eggs hatch into white Nymphs which attach themselves to the underside of plants' leaves with a wax-like coating. These Nymphs are non- feeding and resemble scales.

The adults spend almost all of their time feeding on plants' juices and hanging out underneath the leaves, making them difficult to notice and expel. A quick shaking of plants will cause the adults to scatter and become visible. While they resemble nice little white moths when magnified, they are very injurious to plants.

These creatures can be controlled as other insects, using organic pesticides or home-made concoctions of household agents, or good-old squashing techniques can be employed with great success.

Biological control agents such as the Whitefly Parasite (Encarsia formosa) and the Whitefly Predator (Delphastus pusillus) can be very effective when used appropriately in pertinent circumstances. Encarsia formosa is a tiny parasitic wasp which incubates inside the Whitefly larvae and emerges to ingest the host. The adults also kill Whiteflies for food. Delphastus pusillus is a little beetle which feed on Whitefly eggs, thus interrupting the reproductive cycle and causing population depletion.

It is our opinion that organic insecticides are usually your best bet when time is a concern, which it is in most cases when bugs are in the midst of killing your plants

Chapter #20: Cloning Clinique pt.1!

This week's article will be a minimalist exploration of various techniques used for "cloning" or propagating "baby" cuttings obtained from a "mother" plant through vegetative reproduction.

The use of an aeroponics unit, such as one described in one of our previous articles, can make the cloning of many plants a snap or breeze, as it were, but many people prefer to use more basic methods, which can be just as effective and productive when perfected.

Many people are familiar with taking cuttings of such plants as ivy, and placing them in a cup or glass or mug or vase of water until they form roots at which time they can be transplanted to pots for growth. This practice is the basis for the mass cutting production routines practised in nurseries world-wide, except for various modifications according to circumstances.

Cuttings taken from herbaceous plants can be successfully rooted in water, moist potting soil, vermiculite, stone-wool, perlite, sand, polyurethane foam, and various other substances and combinations.

It is best to take cuttings of stems inter-nodally (between leaf junctions) and to include at least one de-leafed node to be inserted into the rhizome (beneath the surface). Large leaves should be removed if possible, leaving smaller leaves to provide preliminary photosynthetic nourishment. Large leaves can kill cuttings when they transpire excessively and dehydrate the plant to be.

Some people insist that using a sharp knife or razor to add cuts to the part of the cutting to be inserted in the soil can speed root formation, and this could be tried to see if it effective for you.

Another technique which has proven to be effective for some plants is to place the freshly taken cuttings into a sealed plastic bag which is then put into a cool fridge over night, allowing the plants to rest and form a callus layer at the cut surface to aid in stress reduction and root propagation.

Cuttings should always be kept in subdued lighting for at least 24 hours, after-which they can be put under artificial lighting or in a well-lit area.

Many people use clear glass or poly. humidity domes, aquaria, or other apparatuses to seal moisture into the cuttings' environmental atmosphere. Others prefer to mist them with water regularly and still others use anti-transpirants (such as wax) to seal in moisture so the cuttings don't dry out.

Exotic rooting hormones such as gels and sprays laced with vitamins and other mystical, magical secret ingredients are usually unnecessary and good old rooting powder will suffice, but to each their own. Fungicides may be required in unkempt, dingy surroundings, but cleanliness can usually prevent fungal infestations.

Chapter #21: Intro. 2 Organic Hydroponics pt.1!

People who have some sort of problem associating hydroponics with organics should stop reading this right now and go put their heads back in the sand. The word hydroponics can be loosely interpreted from Latin to mean "working-water" (not "non-organic" as some people seem to think), and since water is allowed for organic growers, hydroponic growers can of course adapt their systems to be fully, or semi-organic.

I don't plan to rant much further, but I have run into many organic exclusionist idealist fervour-spewing radicals who refuse to categorise any hydroponics methods as possibly being organic off hand, without any consideration.

Now on to the more enjoyable technical aspects of organic hydroponics.

Organic substances are defined as those substances obtained directly from Mother Earth without chemical alteration or processing, and including those produced by plants or animals.

A completely organic hydroponics system must use only organic materials for the substrate or media in which the plants are intended to grow, and must utilise only organic fertilizers to supply the necessary nutrients for the plants to grow and flourish.

The growing media can be soil (steam or heat sterilized preferably to prevent disease or fungal infestation), vermiculite, perlite (pearlite), peat, coco-husk (coir), straw, or other organic material(s). I’m not sure whether stone-wool is classified as organic by the organic classifiers, but seeing as it is just physically treated (heated and spun) rock from the Earth, I think it should be, although I don’t use or praise it anyway, but some people have been convinced to like it (fanatically in some cases).

Organic fertilizers come from a vast array of sources including bat guano; sea-bird dung; sea-weed ("strip-mined" or "clear0cut" from the oceans); fish entrails and bones; cow, pig, sheep, chicken manure, bones, blood, and urine; and a myriad of other places.

The main problems with using organic fertilizers are nutrient completeness and control issues as well as contamination problems. Nutrient variations between batches and sources of organic nutrients make fetilizer cycling much more difficult than with conventional "chemical" solutions, causing increased runoff into the environment in some cases where ion imbalances occur. Fertilizers such as manure are also sources for possible outbreaks of E. coli bacteria when crops are not processed properly.

When using organic nutrient solutions in hydroponics it is best to discard waste effluent by using it to fertilize ornamental or outdoor crops to minimize environmental damage.

Chapter #22: Hydroponic Jalepenos!


One of the easiest and most delectable crops I ever grew was a small batch of hydroponic Jalepeno peppers grown indoors under artificial lighting.

I set up a small grow-room ~4' x 4' and covered the walls with clean, reflective white plastic. I erected a 3' x 3 & 1/2' ebb & flow tray on top of a piece of plywood supported by empty 5 gallon pails, with a 15 gallon reservoir underneath to hold the nutrient solution. Inside the reservoir was placed a small aquarium water pump with hose to feed the grow-tray through a thru-hull fitting which was purchased from the boating supply section of a local hardware store.

The lighting system I used was one 400 Watt Metal Halide standard bulb in a vertical (base-up) reflector fixture with remote mounted ballast. I didn't bother to measure the light levels throughout the room as I presumed I would have enough light, and could always add some fluorescents if need be.

The substrate chosen in which to anchor the plants roots was pure medium-grain sized horticultural-grade Vermiculite because peppers require and flourish in moist areas.

The media was flushed with 1/2 strength fertilizer solution to "charge" it with nutrients as it had none to begin with and would have depleted the first batch in the cycle if this was not done.

Pepper sprouts which were incubated under fluorescent lights for a week were transferred to the hydroponics tray and left to grow under 16 hour light "days" and the tray was flooded once a day with solution initially and twice after 3 weeks when the plants were larger.

The pH of the solution was checked once a week using an aquarium test kit and it did not require adjustment due to the Vermiculite's natural neutral state combined with the slight acidity of the fertilizer which kept the system's level at the optimal value of pH ~6.

The fertilizer used was a commercial-grade powder type and it was mixed according to the directions, using ½ strength for the first week and regular full strength after that. The EC was not checked and the system was flushed with clean water every 3 weeks and replenished with fresh nutrients.

Due to the cleanliness of the room, no problems with fungi or pests such as whiteflies or spider-mites occurred and a huge batch of plump, succulent peppers was harvested with 8 weeks.

Chapter #23: Organic Plastics!

Most all modern plastics can be classified by definition as being "organic" because they are made of compounds containing Carbon atoms.

There is now a new breed of plastics known as Polylactide Polymers (PLA) being developed by Cargill Dow Polymers LCC®©™. These futuristic plastics will have a myriad of broad-reaching uses including everything from making clothes to being used as hydroponics media.

Although many long-lasting, clean plastics are available already, as outlined in our previous article "Helllloooo Poly.!", these new plastics are heralded to be increasingly environmentally friendly due to the fact that they are readily recyclable and can actually be composted if desired. In contrast, many plastics in use today are designed to be so indestructible that they remain intact while buried in landfills and can take hundreds, if not thousands of years to fully decompose if they are not recycled.

The new PLA plastics are made using carbohydrate sugars extracted from crop plants such as corn, and they are also hoping to be able to be make them from recycled plant material and organic waste products in the future.

These plastics will be especially useful in agricultural circles for use in many areas such as potting mixes, seed trays, and hydroponics media to name a few.

Currently polyurethane and other plastics are used to make durable rooting substrates which can be steam-sterilized and used almost indefinitely until they are so packed with roots that they must be thrown away or recycled if possible. The new plastics will be able to be composted or used as mulch or soil amendments outdoors directly, saving the environment and money.

A couple of good links are: http://www.dow.com http://www.cdpoly.com

Chapter #24: Hydroponic Lettuce!

Sometime in the last millennium, at about this frosty time of year, I set up a hydroponics unit for a "friend" in their basement to grow some lettuce, and in this week's article I'll describe how I did it.

First, I hanged an old light fixture which contained four four foot forty Watt cool white fluorescent tubes. I used chains attached to sturdy hooks screwed into the ceiling beams, or floor joists above, depending on how you look at them.

I then taped durable, easy to clean reflective white plastic in a drape-like fashion around the perimeter of the fixture to focus all of the available light inwards towards where the plants would soon be situated.

Next, I placed an old square three foot by four foot growing tray on top of some old recycled five gallon wine juice pails.

I used an old twelve volt utility pump placed inside a large plastic reservoir to supply the nutrient solution to the tray above. The pump was powered by a power supply and it had a piece of polyethylene pipe attached from it to the tray through a thru-hull fitting (with plastic mesh placed over the end for filtration of chunks of substrate) to allow for flooding and draining of the tray.