Hydroponics is the science of growing plants in containers without soil to which is added a carefully balanced water and nutrient solution. Historically, hydroponics setups included:
- Hanging gardens of Babylon
- Floating gardens of Kashmir
- Aztecs, Indians of Mexico on rafts
- US Government in WWII in South Pacific
- NASA in space
- European community turning to commercial hydroponics
Why is hydroponics better?
- Increased yield better use of nutrient = growing tim = better access to nutrient
- Increased density = plants closer
- Better quality = more marketable = more $
- Less water
- Less pests and diseases
- No weeds
- Quicker crop turn around
- Initial set up cost increased
- Disease can spread quicker
- Nutrient management required
nitrogen, potassium, phosphorous and other sub-elements to turn these into food.
In hydroponics, these are instantly available to the plant in the bottle as nutrient and in turn grow quicker, bigger and healthier. Also they access better O2 (oxygen) than in soil around the roots, thus "breathing" better. Root O2 is a major factor in hydroponic success.
Essential to plant growth and development include:
Carbon (C) Organic compound.
Hydrogen (H) Organic compound. Cation exchange between plant and medium.
Oxygen (O) Organic compound. Anion exchange between root and medium.
Nitrogen (N) Cell development = leaf, stem, root, acts with "green" chlorophyll to give protein to plants.
Phosphorus (P) Blooming, early growth and root development. Adds to hardness, increases maturity and seed.
Potassium (K) Disease resistance, develops carbohydrates, sugar and starch. Increases fruit production.
Calcium (Ca) Translocation of carbohydrates, healthy cell walls, strong stem, membrane and root development. Antioxidant to iron toxicities.
Magnesium (Mg) Absorption and translocation of phosphorus. Activates enzymes. Helps form fats and oils. Useful in CO2 assimilation.
Sulphur (S) Oil production, cell wall, protein production.
Iron (Fe) Catalyst in photosynthesis, respiration. Forms sugars and starch. Activates enzymes.
Chlorine (Cl) For photosynthesis as an enzyme activator of oxygen from water.
Boron (B) Carbohydrate transporter.
Manganese (Mn) DNA and RNA formation through fatty acids. Gets oxygen from water during photosynthesis.
Copper (Cu) Internal catalyst, electron carrier. Involved in nitrogen fixation.
Zinc (Zn) Chlorophyll synthesis. Auxin metabolisation.
Molybetenum (Mo) Electron carrier in converting nitrate to ammonium. Nitrogen fixation and reduction.
Grow nutrients = increased nitrogen = leaf, stem, root growth
Bloom nutrients = increased potassium and phosphorus = fruit, flower development
Must hold water yet drain and oxygenate.
Expanded Clay is a porous, lightweight, earthy clay aggregate. It is durable and has exceptional capillary properties. The internal structure absorbs nutrient solution, releasing it to the plant on demand. It holds the plant in place but is light enough to allow air penetration to the roots, which prevents excessive acidity and rotting. Expanded clay is pH neutral. Best used in recycling systems.
Perlite is a volcanic mineral, small black crystal-like when mined. It is heated to 1100Â°C, then explodes like popcorn to form white/grey granules similar to rice bubbles in look. Very light, sterile and pH neutral. Best for recycling and non-recycling systems.
A flaky material, when heated exfoliates, splitting the layers apart and giving light, spongy, golden granules. It can hold 67% by volume of water. Very light, sterile and pH neutral. Best used as 2 parts perlite to 1 part vermiculite to give optimal water/air ratio. Will break down over time. Best for non-recycling systems.
Internationally used in around 80% of commercial systems. Rockwool is a fibrous material formed from volcanic rock, limestone and coke melted at 1500Â°C. The molten substance is spun, pressed and cooled into cubes and slabs. Excellent water/air ratio. It is pH alkaline to begin, soak in nutrient solution for 24-48 hour then run at 5.2 Ã 6.2 pH. Best in recycling and non-recycling systems.
Photosynthesis - Converts carbon dioxide and water using light energy to sugars (plant food)
Photoperiodism - Day and night light cycle. Used in two phases, vegetative (grow) and reproductive (bloom)
Metal Halide (MH):
- 400 W = 20,000 hour life and 65% lumen maintenance
- 1000W = 12,000 hour life and 75% lumen maintenance
- Metal Halide generate 90-125 Lumens per watt
- MH are basically a mercury vapour with sodium and syconium iodide and a thorium coated electrode.
- Gives the correct spectrum
- Visibly a white light, but has a high blue and green content
- Blue and green light promotes healthy root, leaf and stem growth. Can flower but not effectively.
High Pressure Sodium (HPS):
- 400 W and 1000W have 24,000 hours life and 70% lumen maintenance.
- High pressure sodium generate 110-140 Lumens per watt
- Visibly and spectrally emits a yellow, orange, red light
- Yellow, orange and red light are highly desirable for better flower and fruit production
They work on a 60/90Â°/120 degree beam angle, so the optimal distance is 39-90mm from plant canopy. Our LEDâ€™s for indoor growing, are developed in co-operation with companies based in Switzerland, Italy, and China and are representing results of long term on field testing and experiences. Our LEDâ€™s have many benefits:
- Super Low Power Consumption. High efficiency, save 30% on your power bill (when running 4 LEDâ€™s) compared with running costs of 600W HPS lamp.
- Low Heat Displacement. Virtually no heat emitted using smart technology to effectively dissipate heat.
- Extremely energy efficient, only consuming 3 Watts per LED.
- Conveniently brace mounted for additional side or indirect lighting.
- Easy to use. Just plug in and use. No other equipment needed.
- Discreetly suspended with stainless steel cables (included).
- Low noise operation. Quiet and discrete internal cooling method.
- No wasted energy or extra cooling equipment needed.
- Featuring LED lighting technology with a wide spectrum of light specifically targeted for plant growth and flowering.
- No harm to your plants through heat or harmful energies such as
- Ultra-violet and Infra-red.
- Each LED lasts for up to 50,000 hours of usage
- Environmentally Safe - contains no hazardous materials
All HID (High Intensity Discharge) lamps require a specific ballast. A ballast is a transformer with a core of thin metal plates wrapped in wire and coated with resin. A control box contains a ballast, ignitor and capacitors.
A good reflector can increase light intensity by up to 30% Points to consider when buying a reflector:
- Heat build up
- The closer the lamp to the reflector = increased reflectivity
- Horizontal lamps reflect more than vertical due to the inverse square law of light intensity (light fades rapidly as it moves from the source).
Cloning is taking a cutting from a mature plant in the vegetative stage and inducing it to grow roots. The clone is a genetic duplicate of the mother plant. The new clone can be induced to flower immediately or can be grown on. Rule of thumb. Don't take more than 30% of the mothers vegetative material and not too old. Cuttings from stressed mother plants will produce disappointing harvest results. Ideally the mother can only be cloned 3 times. The real secret is to maintain a healthy, vigorous mother plant stock to take high yielding closes from.
Choose a mother plant with the following:
- Aesthetic qualities
- Heavy flower production
- Short compact growth
- Disease and insect resistance
- Early maturation
- Easily clones
Single cell micro organisms controlled through prevention and elimination. Examples are; bacterial blight, stem rot, bacterial wilt, leaf spot, soft rot and crown gall. Sterilisation of hydroponic systems using weak household bleach will cleanmost bacterial problems.
Formed through spores, fungi are multi-celled organisms. The best example is powderry mildew, a whiteish powder on stem and leaves. Spores are carried via wind and nutrient moving through the system. High humidity conducts the disease. Use sulphur and copper based perticides to sertilise the system. Remove infection.
Botrytis is a common grey-mould fungus that attacks ornamentals. Symptoms include; soft rot and grey mould on older dead tissue. Common on carnations, chrysanthemums, roses, azaleas and geraniums. To prevent, reduce humidity by ventilating and sterlising environment. This reduces spot transfer.
Also called eelworms are parasites living in plants, soil, hydroponic media and water. Almost invisible to the naked eye, nematodes attack roots and leaf buds. Root knot nematodes stunt growth and wilt plants. Remove infested plants early and sterilise media next crop. Leaf and bud nematodes cause fruit or leaf distortion in ornamental and strawberries. Note yellow spots turning black on lower leaves. Can be controlled by pesticides.
Also called two spotted mite and red spider mite are most common. Almost invisible they live on the underside of leaves sucking plant sap. Yellow speckles occur. Most prevalent in hot, dry months. Combat by spraying every second day once mites appear. Spray with natural pyrethrums or Clensel to kill the mites once they hatch. Spraying won't kill eggs.
A waxy white moth like insect about 3mm sucks sap from the underside of leaves and stem. Infested plants grow poorly and look yellow. Best control is biological using parasites (Encarsia formosa) to kill eggs. You can use natural pyrethrum sprays also.
Soft bodied insects attack under tips and underleaves. They suck sap and spread disease. They spread shiny honeydew accumulating into a choking mould. Aphids are born as pregnant females and reach adulthood in 1 week. They are lethal. Control using lady birds and green lacewing.
Algae occurs when light, water and oxygen mix. To prevent algae growth cut off light to infected area. Algae robs the system of oxygen but some say it produces certain beneficial enzymes. The only serious problem with algae is when it builds up blocking drainage or feed lines or where is harbours insects and diseases. To clean use 10% bleach solution before planting next crop.
|Ladybird||Aphid, mealy bug, citrus mealy bug, mealy bug eggs|
|Praying mantis||Most insects|
|Lacewing||Apid, citrus mealy bug, spirder mite, thrip and many worm eggs|
|Predatory mite||Spider mite|
|Parasitic wasps||Citrus mealy bug|
|Scale predators||Scale insects|