You have 0 items in your cart. 
Frequently Asked Questions
Click on the link closest to your question or scroll and read all the faqs.
- Hydroponics Basics
- Nutrient and pH
- Hydroponics Systems
- Pests and Diseases
- Plant Lighting
- Ventilation and Air Filtration
- CO2
- Propagation
- Greenhouse Gardening, Indoor Gardening, Fodder Farms
- Aquaponics
1. The Basics
What is Hydroponics?
Hydroponics is a form of gardening/farming that does not need soil in the traditional sense. Instead, all the nutrients that a plant needs to grow and thrive are delivered directly to the root zone via the watering system. "Soil" is needed in the form of an inert medium (like Perlite, Rockwool, Clay pebbles or Coco Fibre) to support the root system. The nutrients can be derived from either inorganic or organic mineral salts.
"Hydroponics" is derived from the Greek "hydro" meaning water and "ponis" meaning work. The literal translation of hydroponics is "water working". Water is the key in any hydroponics system and it is therefore extremely important that the water supply used is of good quality.
What can you grow hydroponically?
Anything that you would consider growing in a conventional garden, can be grown hydroponically.
Once you have worked out what you want to grow a system can be designed accordingly. It is important to note that for crops like root vegetables you will need to have a media based system with a deep enough container to support the development of the root vegetable. For other crops like tomatoes, capsicums, cucumbers or even flowers like roses, carnations, tulips there are many options from which to choose. Anything from hand watering, drip irrigation, NFT (Nutrient Film Technique), Flood and Drain and other basic recirculating as well as aeroponic systems, can be used. For more info see the System section and for a more detailed list of crops that are commonly grown hydroponically see the Nutrient Chart.
What is the difference between growing in soil (i.e. conventional gardening or farming) and growing hydroponically?
The most notable difference is of course that all nutrients for plant development are provided via the watering system rather than via the soil.
The roots of the plant in a hydroponics system do not need to search for food as they would in a soil/conventional garden.
Because the nutrients are provided directly to the root system, plants grown hydroponically will grow faster and also stronger than plants grown in soil. The direct application of nutrient to the root-zone also means that the root systems of hydroponically grown plants are smaller than soil grown plants. This has the added benefit of being able to grow more plants in smaller area than conventional farming.
The most significant difference (particularly in this period of water restrictions and drought) is that hydroponically grown plants use water more efficiently than soil grown plants. As an example, in a commercial situation, to produce $100 worth of lettuce in a conventional farm requires the use of 38,000 litres of water, in a hydroponics farm only 600 litres is used. (Practical Hydroponics and Greenhouses Magazine Jan/Feb 07 page 1 and 18)
Hydroponic Gardening has the potential to be a more sustainable approach to agriculture then conventional farming. It not only maximises crop production in a smaller area and uses less water it also uses fewer pesticides and has little or no need for herbicides. Pests and weeds are not a problem in a hydroponic system if it is set up and managed properly. IPM (Integrated Pest Management) systems are becoming more widely used by commercial and hobby growers alike. IPM systems incorporate the use of beneficial bugs or predators and non-toxic sprays (like Aza Max and Eco Oil that are BFA Certified Inputs) as part of a programme to combat and treat unwanted insects like Spider Mite, Fungas Gnats, White Fly, Aphids and Mealy Bugs to name a few.
Having said this, perhaps the greatest advantage in growing hydroponically is the potential to produce commercial quantities of fresh nutritious food for a continually growing population on land that has and will become nutrient deficient and pesticide rich due to intensive conventional farming practices.
Is Hydroponics organic?
There is an ongoing debate in the industry as to wether you can have organic hydroponics. For some, it is a contradiction in terms, since the whole idea of growing hydroponically is that you avoid all the pitfalls of organics in the growing system, like pathogens, diseases, pests etc as well as having less control of nutrient input. There are those that argue that you cannot get the same level of nutrient availability in an organic system as you can in a true hydroponics system and there are those that argue that organics in hydroponic gardening is the only way forward.
Growing methods have become more dynamic & fluid in their practical applications as more is understood about the whole process of plant growth and it is no longer true to say that one method is necessarily exclusive and better than another. It is therefore possible to use aspects of organic and biodynamic principles in a hydroponics system. The most common aspects used are biological controls. This includes IPM (Integrated Pest Management). IPM encourages the use of natural predators to fight pests as opposed to chemical sprays. This principle takes into consideration the role insects play in the natural world.
Another biological control used is the addition of beneficial microbes and enzymes to the growing medium. These additives are designed to encourage micro life in the medium as a means of promoting a healthy root system and of course a much healthier and therefore productive plant. This is not a sterile system, in that no harsh sterilising agents like chlorine or hydrogen Peroxide are used to kill all pathogens. Instead the natural process is considered, whereby there can exist beneficial as well as harmful micro-organisms in the growing system. The idea is that an environment is created where the beneficial micro-organisms outnumber the harmful, thus allowing the vigorous growth & development of the plants without the need for fungicides or harsh sterilising agents. The use of enzymes and fungi such as Trichoderma in the growing medium has become more common as their benefits become more widely understood.
There are also some certified organic nutrients on the market. The strongest formulation designed for the hobby market is called Bio Canna. This is made in Holland. Another is called Bio Juice. This is made in Australia and is BFA Certified.
Alternatively, you can use worm castings, liquid seaweed depending on the concentration liquid fish fertilisers like Amino Gro. As long as the formula has a balance of all Macro & Trace elements it is safe to use. (See Nutrient & pH) The logical extension of organics in hydroponics is Aquaponics.
Aquaponics is the combination of Aquaculture and hydroponics. Fish are farmed and their waste products provide the nutrients to grow plants. (See Aquaponics) The benefits of this kind of system are that it encourages all the beneficial micro-organisms to thrive and strengthen the crops being grown.
In the current climate where there is growing discontent with the use of chemicals in the production of food, organics in Hydroponics is not only viable but essential.
2.Nutrient and pH
What is "nutrient solution"?
"Nutrient solution" is a term used to describe the dissolved fertiliser in water.
Nutrients are available in powder or liquid form. Liquids are more popular than powders because they are easier to use. There are many brands of liquid nutrient on the market today and they should all have the following essential breakdown of Macro & Trace elements. The Macro Elements are the main building blocks of nutrition for plants to thrive. They are essential elements and should be present in greater amounts than the Trace elements
The Macro elements are:
Nitrogen (N)
Phosphorus (P)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Sulphur (S)
The Trace elements are:
Iron (Fe)
Manganese (Mn)
Zinc (Z)
Copper (Cu)
Boron (B)
Molybdenum (Mo)
These elements should be in an all round fertiliser be it liquid or powder. The concentrations of Nitrogen Potassium and Phosphorous will vary depending on the crop. If you are growing a predominantly flowering or fruiting crop you should consider an increase in phosphorus and potassium from the start of flower / blossom formation.
What is PPM, CF & EC?
There are three scales commonly used for measuring nutrient solutions in a Hydroponic system. All three scales refer to density of the test solution once nutrient has been added. They do not provide an analysis of any macro or trace elements but do provide a measure of overall nutrient strength. Measuring nutrient strength is important. Without this measurement it is impossible to know how much or how little nutrient to feed plants. Nutrient requirements vary depending on, not only the type of plants that are grown but also their stage of development. For example Tomatoes and Capsicums require more "food" or nutrient than lettuces (see Nutrient Chart) and seedlings need less food than maturing plants.
EC (Electrical Conductivity) is measured with a conductivity meter. This meter passes week electrical current between two electrodes. The strength of the solution determines the amount of electricity the solution conducts. Essentially an EC meter measures the ability of an aqueous solution to carry an electric current. EC is a measure of electrical charge between two points in milli-siemens (mS/cm) or micro-siemens (µS/cm).
PPM (Parts Per Million) measures how many parts of a fertiliser are in every million parts of water.
CF (Conductivity Factor) relates to EC. It is simply a measure of EC multiplied by 10.
In order to measure in either of these scales you will need to invest in a meter. The most common and user friendly meter on the market is known as a Bluelab Truncheon. It will give a reading in all three scales and does not require calibration.
A comparison chart is included for your information so you can see the relation between all three scales.
E.C |
CF |
PPM |
0.2 |
2 |
140 |
0.4 |
4 |
280 |
0.6 |
6 |
420 |
0.8 |
8 |
560 |
1.0 |
10 |
700 |
1.2 |
12 |
840 |
1.4 |
14 |
980 |
1.6 |
16 |
1120 |
1.8 |
18 |
1260 |
2.0 |
20 |
1400 |
2.2 |
22 |
1540 |
2.4 |
24 |
1680 |
2.6 |
26 |
1820 |
2.8 |
28 |
1960 |
3.2 |
32 |
2240 |
3.6 |
36 |
2520 |
What is pH?
pH is the measure of dissolved hydrogen in a solution. The literal meaning is "parts of hydrogen". The scale ranges from 0-14 where 0 is the most acidic and 14 is the most alkaline and 7 is neutral. In a hydroponic system it is important to monitor the pH of the nutrient solution and adjust it accordingly if it is out of the ideal range.
pH determines the ability of the plant to absorb the Macro & Trace elements in the nutrient solution. This is also known as "nutrient availability". The correct pH allows for the best absorption of all available macro and trace elements in the nutrient solution.
pH is very important. If the pH of the nutrient solution is out of its ideal range certain nutrient elements will not be available for the plant to absorb and nutrient deficiencies and toxicities can occur. The optimum pH is determined by the range at which all elements- both Macro & Trace, are best available.
The optimum pH range for Hydroponic or "water culture" systems is around 5.5-6. Hydroponic or "water culture" systems require a more acidic pH than soil/conventional gardening systems. This detail is sometimes overlooked in some older hydroponic gardening texts.
How do you measure pH?
pH is measured with a pH test kit or a pH meter. Test kits are usually made up of a liquid and a vial. To test a nutrient solution you place a small amount of the nutrient solution in the vial and add a drop of the liquid. The colour of the test solution will change and can be checked against a colour chart to determine the pH.
A pH meter will give a digital read out of the test solution. Meters are easy to use and inexpensive. They require calibration periodically to maintain their accuracy. The most commonly used pH meters are made by Eutech. (See online shop)
How do you adjust pH?
Once you have taken a pH reading you either lower or raise the pH with acidic or alkaline concentrate solutions. To lower pH, you will need something acidic, this is usually phosphoric acid. To raise the pH you will need to use potassium hydroxide which is an alkaline solution.
Nitric acid is used by some commercial hydroponic growers to lower pH, but it is very volatile and is not recommended for the home or hobby grower.
Phosphoric acid has become the standard for lowering pH. Because of its high concentration only very small amounts are needed to lower pH. It is important not to use too much phosphoric acid, as this can affect the nutrient composition.
There are also some organic acids on the market. Canna has developed Organic Acid for the hobby grower, and there is also a concentrated Acetic Acid made by Bloom Nutrients. The main problem with using Acetic Acid is that it may not remain stable in the nutrient solution, especially in hard water. The makers of Bloom Nutrients are currently trying to solve this problem.
Is the pH in a hydroponic system the same as pH in soil?
It is a common mistake to assume that the pH of plants is the same in a soil medium as it is in a hydroponic medium. This is not the case. The pH requirements in a hydroponic system are skewed in the acidic range. As an example, the pH at which most nutrients are most available in a hydroponic system is 5.5 whereas it is 6.5 in soil.
What is the ideal nutrient & pH of a hydroponic system?
The ideal nutrient strength & pH strength depends on the plants you are growing and the stage of growth. For most crops a nutrient range of 12-24cF and a pH range of 5.5-6.0 is suitable
The chart is a rough guide and it should be remembered that nutrient requirements could vary depending on environment. If you cannot adequately control the temperature of both the growing area and the nutrient solution being fed to the plants you will need to adjust the nutrient strength accordingly. For example, in times of extreme heat a lower nutrient strength is recommended.
What are the functions of all essential plant Elements?
Carbon
Forms up to 50% of the dry weight of a plant.
A constituent of all organic compounds that are found in plants
Hydrogen
Part of all organic compounds that of which carbon is a constituent.
Comprises 6% of dry weight of the plant and
Is critical in the cation exchange in plant-soil/medium relationship
A major constituent of plant structure when combined with Oxygen to create water.
Oxygen
Plays a critical role in plant growth
Oxygen is about 88% of the composition of water.
Plants obtain the oxygen they need through the stomata on the leaves, through the roots via the water and through the process of photosynthesis.
Involved in Anion exchange between the roots and surrounding medium
Nitrogen (N)
Essential for production of chlorophyll
Essential for controlling oxygen level in plants
Oxygen from the Nitrate (NO3) form of nitrogen is used to break down carbohydrates produced by photosynthesis
Plays vital role in the formation of protein
Needed in highest concentrations at growing points such as young leaves, root tips and fruits and flowers.
Mobile element so deficiency symptoms appear first in older leaves.
Phosphorus (P)
Important element for turning starch into simple sugars that can be metabolised by the plant
Deficiency inhibits fruiting
Phosphate (PO4) is concentrated in seeds, fruits and merismetic tissue
Mobile element so deficiency symptoms appear first in older leaves.
Potassium (K)
Stimulates root development and is essential for the good growth of plants.
Functions as a catalytic agent
Merismetic tissue , buds, young leaves and root tips are rich in potassium
It is a mobile element so it can be found all over the plant but is concentrated in areas of high physiological activity
Mobile element so deficiency symptoms appear first in older leaves.
Calcium (Ca)
Helps to reduce toxic effects of other mineral salts
Aids in protein synthesis
It is a vital element and is the basis upon which the cell structure is built
No calcium equals no growth at all
Immobile element so signs of deficiency appear on the tips of the shoots & roots
Magnesium (Mg)
Essential for the formation of chlorophyll and as a carrier of phosphorus
Mobile element so deficiency symptoms appear first in older leaves.
Sulphur (S)
Building block for plant protein, amino acids & coenzyme A, vitamins thiamine & biotine
Improves chlorophyll supply
Important for health of root system
Affects nitrogen assimilation
Immobile element so deficiency symptoms appear in younger leaves first
Iron (Fe)
Acts as an oxygen carrier and enzyme catalyst
Critical for the production of chlorophyll, protein synthesis and respiration
Balances Manganese (Mn) and prevents manganese toxicity
Under alkaline conditions Iron can combine with phosphates, carbonates and hydroxyl ions so it is important to maintain the correct pH fro maximum iron availability.
Immobile element so deficiency symptoms appear in younger leaves first
Boron
Influences ratio in which anions and cations are taken in by the plant
Enhances the uptake of cations and limits the uptake of anions
Influences carbohydrate and nitrogen metabolism
Helps with plants use of calcium
Essential element in nitrogen and carbohydrates metabolism
Immobile element so deficiency symptoms appear in younger leaves first
Manganese (Mg)
Catalyst
Involved in carbohydrate metabolism and chlorophyll formation
Accelerates plant growth in conjunction with nitrogen
Highest concentrations occur in the leaves
Immobile element so deficiency symptoms appear in younger leaves first
Zinc (Zn)
Utilization of Zinc by the plant is directly related to the amount of light available to the plant
The more light available the greater the uptake of zinc resulting in higher metabolic activity
It is an enzyme activator and a component of indoleacetic acid ( a plant growth hormone)
Mobile element so deficiency symptoms appear first in older leaves.
Copper (Cu)
Influences disease resistance of plants
Syntheses chlorophyll
Increases enzyme activity
Immobile element so deficiency symptoms appear in younger leaves first
Molybdenum (Mb)
Converts Nitrogen gas from the air into soluble nitrogen compounds by nitrogen fixing micro-organisms
Essential for conversion pf nitrate to proteins
Immobile element so deficiency symptoms appear in younger leaves first
Chlorine (Cl)
Functions as an enzyme activator in the process releasing oxygen from water
Critical factor in drought resistance of plants because of its affect on tissue water content
What are the symptoms of nutrient deficiencies and toxicities?
Nitrogen (N)
Deficiency Symptoms
Symptoms appear first in the older leaves
Leaves pale green
Lower/older leaves are yellow drying out to light brown colour due to lack of chlorophyll
Plants mature earlier with reduced yield
Growth is stunted
Toxicity Symptoms
Leaves are dark green and soft
Plant is bushy with restricted root system
Flowering delayed
Phosphorous (P)
Deficiency Symptoms
Symptoms appear first in older leaves
Older leaves purpling sometimes bluish grey and sometimes yellowing
Plants are stunted and slow growing
Roots can be yellow/brown in colour
Leaf curls
Toxicity Symptoms
Causes zinc and iron deficiency
Older leaves yellowing
Leaf tips become yellow/brownish followed by necrotic spots
Leaf abscission develops
Mature leaves appear crushed/wrinkled
In extreme cases the leaf internodes will harden and bright dry spots may appear on leaves or fruit
Potassium (K)
Deficiency Symptoms
Symptoms appear first in older leaves
Necrosis (i.e. yellowing to brown spots ) of older leaves starting at tips and between veins
Toxicity Symptoms
Rarely occurs because plants do not generally over absorb potassium, however too much potassium can cause deficiencies in other elements like magnesium, iron, zinc and manganese.
Calcium (Ca)
Deficiency Symptoms
Symptoms appear first in younger leaves
Causes blossom end rot of Tomatoes & capsicums, tip burn in lettuce & cabbage, internal brown spots in potatoes
Deficiencies first appear growing point and in the fruit
Tips of shoots and roots turn brown and die
Toxicity Symptoms
No direct symptoms, but toxic levels of calcium will have an effect on iron, potassium or magnesium levels
Magnesium (Mg)
Deficiency Symptoms
Symptoms appear first in older leaves
Inter veinal chlorosis
Loss of green colour
Dead brown margins and spots on leaves
Combined with strong light, a Mg deficient plant will look withered
Premature leaf drop
Toxicity Symptoms
Extremely uncommon
Sulphur (S)
Deficiency symptoms
Symptoms appear first in the younger leaves
Symptoms slow to develop and resemble nitrogen deficiency
Plants stunted, light green & woody
Internodes longer then usual
Yellowing (chlorosis) appears in older leaves
Toxicity Symptoms
General hardening of plant
Leaves bluish-green
Stems become hard & leaves are smaller
Leaves may curl inward & become pimpled
Iron (Fe)
Deficiency Symptoms
Symptoms appear first in the younger leaves
Growing tips turn yellow, veins remain green (interveinal chlorosis)
Occurs in younger leaves
Toxicity Symptoms
Extremely uncommon
Boron
Deficiency Symptoms
Symptoms appear first in the younger leaves
Growing points die
Leaves mottle and flower stems roughen
Buds die
Leaves become yellow/brown and curl inward
Toxicity Symptoms
Leaf tips become yellow then scorched
Leaves drop
Manganese (Mg)
Deficiency Symptoms
Symptoms appear first in the younger leaves
Interveinal chlorosis
Stunted growth
Toxicity Symptoms
Curling in of leaves
Death of the growing point
Scorched leaf margins
Brown spots on older leaves
Reduction in growth
Zinc (Zn)
Deficiency Symptoms
Occurs in conditions of extreme heat and intense light
Younger leaves show first signs and are abnormally mottles with chlorotic spots and upward curl
Internode length and leaf size are reduced
Toxicity Symptoms
Manifests as Phosphorous or iron deficiency but is uncommon
Copper (Cu)
Deficiency Symptoms
Young leaf chlorosis
Stunted growth
Green blue leaves
Burned margins
Toxicity Symptoms
Stunted growth
Symptoms of iron chlorosis
Reduced branching
Thickening and darkening of rootlets
Molybdenum (Mb)
Deficiency Symptoms
Immobile element
Symptoms progress from older leaves to younger leaves
Leaves show a pale green to yellow interveinal mottling.
Can be confused with nitrogen deficiency
Toxicity Symptoms
Not common.
Tomato leaves can turn a golden yellow
Chlorine
Deficiency Symptoms
Extremely uncommon in hydroponic systems
Affects root structure & metabolism
Toxicity Symptoms
Leaves are small and dull green
Plant becomes woody
What treatments are recommended when there is a nutrient deficiency or toxicity?
First check the nutrient being used contains an adequate mix of all Macro & Trace Elements. Any well known nutrient manufacturer will have a well formulated nutrient.
A deficiency in any nutrient element will occur for a number of reasons, the two most common are a) the nutrient strength is insufficient (i.e. not strong enough) and b) the ph is incorrect. Other environmental factors including temperature in the growing area as well as the water can affect nutrient uptake. As a gardener it is important to provide the best growing environment for your plants, any deviation from this can produce deficiency or toxicity symptoms.
To treat for toxic levels of any nutrient element, flush with pH adjusted fresh water and then adjust nutrient to correct EC/cF
Check that nutrient strength (EC/cF) and pH are at the right level. As an average the EC should range from 1.2 in the early stages of growth gradually in creasing to 2.0EC and a maximum of 2.4 EC for flowering/fruiting crops in the middle of their blooming stage, dropping back to 2.0ec closer to harvest. Optimum pH is 5.5. At this range the plants can absorb the most nutrient elements in a hydroponic system
Check water temperature – Temp. should be no more than 25degress Celsius
Check glasshouse/room temperature. Optimum temp is 28 –30 degrees for day time and 18-20 degrees at night (Can vary depending on type of crop)
Check watering system, making sure there is neither too much nor too little water being fed to plants. If the medium is kept too wet it can inhibit root development and contribute to overall ill health and potential root rot of the plant. The medium in any hydroponic system needs to be kept moist but not saturated so allow ample time between feeds for the medium to begin to dry out before you feed again.
3. Hydroponics Systems
What is a Recirculating System?
Recirculating systems, as the name suggests, are based on nutrients being circulated either continuously or intermittently
The main issue of system management for this type of system is the increase in nutrient strength and pH as the nutrients are fed and then returned through the system. The increase is more apparent in media based systems then water based systems.
What types of Recirculating systems are Available?
NFT
NFT is the acronym for Nutrient Film Technique. The system uses lengths of channel connected to a reservoir. The nutrient solution is pumped from the reservoir through the channel and returns back into the same reservoir. Simply put, the system works by pumping a thin layer of nutrient over the root system at all times.
This is very productive system for growing lettuces, herbs particularly basil, Asian greens like bok Choy and strawberries. Tomatoes, capsicums and cucumbers can also been grown in this system with success. The channel comes in different widths & depths. The narrow channel [100mm (w) x 50mm(h)] is better suited to leafy greens, while the wider channel [115mm (w) x 70mm(h)] is suited to Tomatoes, capsicums, beans and any crop with a medium to large root system.
Power Grower TM
This is a novel self contained unit. The reservoir is contained at the base of the pot itself and nutrient is forced via the use of an air pump from the base to feed from the top. This is known as a Venturi system. The medium used in the top part of the pot is clay pebbles. This system does not require a timer because it waters continuously. Clay pebbles are used because they have a low water holding capacity making them ideal for continuous watering. This system makes the most of a small space. It uses an air pump and constant watering to provide an ideal balance between nutrition and aeration.
Flood and Drain (Also known as Ebb & Flow)
A Flood and Drain system, as the name suggests, is based on nutrient "flooding" the medium at intervals. The system works by pumping nutrient solution from a reservoir into a tray full of medium and allowing it to drain back into the same reservoir. The nutrient solution is pumped for a period long enough for the medium to be fully covered without it being saturated. The choice of medium is important. It needs to be porous enough that it does not become water logged and have enough water holding capacity that it doesn"t dry out too quickly. The most common types of medium to use are Clay Pebbles (also known as HydrotonTM) and MaidenwellTM Daitomite (a type of diatomaceous earth mined in QLD)
A Flood & Drain system is made up of a tray, fittings for the feed and drain, water pump, an air pump and air stone and a timer. The trays come in the following sizes;
630mm x 1100mm
900mm x 900mm
1160mm x 1160mm
1040mm x 2040mm
The fittings suit all these tray sizes and are made up of a 13mm drain and 19mm feed. It is important to have a smaller drain size than feed size so the tray not only floods evenly but so there is enough time for the entire medium in the tray to get enough nutrient. As with all systems there is a fine balance between feeding enough nutrients and feeding too much. That is, watering too little and too much. The exact amount of time required for each feed and the number of feeds is dependent on the size of the tray (which determines the amount of medium in the tray) the size of the water pump and ultimately environmental factors like temperature. In sunny hot conditions more feeds may be needed and in cold conditions less would be needed. As an example it takes about one minute to feed a 630mm x 1100mm tray filled with Maidenwell using a 1400l/h water pump. In moderate conditions feeding three times a day in this size tray is sufficient.
Recirculating Pot System
This recirculating system involves setting up a series of pots or containers attached with irrigation hose so they are all linked and form a closed circuit. A reservoir with a ball float (often called a "brain" or "heart") is needed to contain the nutrient solution as well as a pump and a timer and also a back-up reservoir. In the pots any medium can be used.
The watering times are varied depending on the choice of medium as each medium has a different water holding capacity. For example perlite holds less water then rockwool or coco fibre and in some respects is better to use in this kind of system if only because it lessens the likelihood of over watering.
The system is very simple to set up and can work quite well if it is set up properly. The pots should have some kind of rocks for drainage usually clay pebbles. This helps the medium to drain properly. The pots should be elevated about 20cm off the ground so they are higher then the nutrient reservoir ("brain"). This makes it easier for the solution to flow back into the reservoir. The nutrient reservoir can be fitted with a ball float so water from the back-up reservoir can flow into it as needed. The backup reservoir needs to be elevated, as you would expect, so it can flow into the nutrient reservoir ("brain"). The system works by pumping nutrient from the "brain" to the pots via irrigation hose and back again into the "brain".
As the nutrient circulates through this system and returns to the "brain" the nutrient strength and the pH changes so it is critical to monitor pH & EC/cF regularly to avoid any nutrient toxicities or deficiencies.
Another important facet of this system is nutrient change and flushing. The nutrient in the nutrient reservoir should be changed every three to four days. This helps keep the nutrient fresh and removes any waste build up. Flushing the system should be done every third nutrient change. To flush, bypass the return hose so it does not return into the brain and pump pH adjusted water through the system in place of one of the feeds. Catch the run-off in another container and use in the garden.
What is a Run-to-waste System?
Run-to-waste systems are very simple to use. At its most basic, a hydroponic system can be made up of any size container filled with either rockwool or coco fibre and hand watered with nutrient once a day or as weather dictates. To take this basic system one step further, a pump, irrigation hose and a timer can be added to make the system fully automated.
The main point to remember in this kind of system is to only water enough to get ten percent waste. In other words if you feed a plant a litre a day only 100ml of waste should come out the bottom of the container. If more then this comes out then simply feed less.
The most common run-to waste system is a Drip Feed/Irrigation System.
This involves setting up a series of pots or a series of slabs, with a reservoir, water pump, air pump and a timer. In this kind of system it is important to select a medium that has a high water holding capacity like rockwool or coco fibre. This is done so the amount of feeds and consequently the amount of run-off is minimised. The pots are linked to the reservoir via irrigation hose and the waste can be caught in a separate container and used in any part of the garden. Waste should be minimal. The ideal waste or run-off should be about ten percent less then this does not allow enough nutrient build up to flush from the medium and any more is unnecessary. The system is in a sense being flushed with every feed so a full flush is only needed once every two weeks at most. A "full flush" in a run-to-waste system is really just replacing one feed with pH adjusted water instead of nutrient. It is not necessary to drop the EC in the medium to 0.0 or to get 0.0 EC run-off and it can actually be detrimental. The root system can be shocked by going from having readily available nutrients in the medium to nothing. If in doubt check the EC of the run-off. If it is higher than the EC being fed then a flush is needed. If it is lower or the same it is fine. It is important to flush consistently, however. This means that if you flush every two weeks or three weeks etc continue to flush every two or three weeks.
An air pump is recommended so that the nutrient solution does not become stagnant. The feeding times in a run-to waste system are very short, usually of one to two minutes and once to three times a day depending on the size of the plants , the size of the pots and environmental factors like temperature & humidity.
What is an Auto pot /Gravity fed system?
Autopot is a system that relies on a "smartvalveTM". This valve acts like a float valve in that it only allows a set level of nutrient into the bottom of the container. The creators of this system describe it a as the "plant driven watering system". The medium commonly used is perlite because of its capillary action (draws nutrient/water up through the medium). The system has been proven both in a hobby garden as well as in a commercial venture.
What is an Aeroponic System?
As the name suggests, aeroponic systems rely on air /oxygen. A basic aeroponic system is known as a "bubbler" system. In this system the plant is grown in a nutrient rich solution of water that is continuously aerated. Root rot does not develop because the water is never stagnant, but instead continuously moving thus increasing oxygen in the water. It is a very effective way to grow hydroponically. A true aeroponic system relies on a series of misting jets that spray the roots with nutrient rich water. The fine mist of nutrients is highly oxygenated. The plants are usually suspended and the roots covered from direct light. Aeroponic systems report rapid growth. The main reason for this is the direct application of nutrient to the roots. In some respects this is a very high maintenance system. It relies heavily on reliable pumps and electricity supply.
What is a Rainforest System?
This is made by General Hydroponics and is a self contained system. Plants are suspended in a reservoir that is completely sealed from light and watered with a Vortex pump producing a fine misting spray, continuously wetting the roots. The roots are hanging in a highly oxygenated nutrient solution. The one draw back to this system is that if the pump fails the plants will not survive for very long. The main advantage is very rapid growth.
What is a Bubbler System?
This works on a similar principle to the Rainforest System except that it is slightly more forgiving. If the pump fails in this system the plants will still survive as long as the roots are still sitting in the nutrient solution. The system is very simple. It uses an air pump with air stones, a container with a lid usually a rectangular container of about 45litre capacity. Into the lid holes are drilled to fit small netted pots. These pots are filled with clay pebbles and the seedlings placed in them so the roots are touching the base of the pots. The container holds the nutrient solution and the air pump and air stones continuously agitate the water so it does not become stagnant and at the same time add much needed oxygen. The idea is that once the lid with the netted pots is placed onto container the roots will grow through the pots into the nutrient solution. The roots are thus in water all the time. The potential for root rot is lessened by aerating the water.
4.Pests and Diseases
What are the symptoms and treatments for Red Spider Mite?
Red Spider Mite are considered a sucking insect. They are usually found on the underside of the leaves and can be black in colour.
Symptoms
- White spots on leaves
- Webbing
- General yellowing of leaves
Treatments
- Predators such as Persimilis and Typhlodoris are reasonably effective but need to be used in conjunction with a spray like Aza MaxTM.
- Systemic sprays like Mavrik and Malathon are available but it is extremely important to follow all safety procedures on these products.
- An effective but safe spray is called Aza MaxTM. It has been certified as an organic input by BFA and treats Whitefly, Fungas Gnats as well as spider mite (Dilution Rates) Aza Max is an anti-feedant. It acts to break the breeding cycle so pest numbers are reduced gradually. The active ingredient is Azadachtrin which is derived from Neem Oil which is in turn extracted from the Neem Tree.
- Eco-Oil is another spray widely used commercially as part of IPM systems and has becoming more widely used by the hobbyist. This is also BFA Certified and should be used as a preventative treatment if the growing area is prone to getting spider-mite.
What are the symptoms & treatment for Sciaridfly (Fungus Gnats)?
Sciaridfly, also known as fungus gnats, are small brown/black flies that are localised around the top of the medium. They lay eggs around the fine root hairs of the plants. The eggs hatch and the larvae survive by eating the fine root hairs. Left untreated the plant will eventually die.
Symptoms
- Small black flies located on top of the medium. Starts to show signs of nutrient deficiencies & root rot i.e. yellowing of leaves, and brown spots.
- The best treatment for sciaridfly (fungus gnats) is a predator called Hypoaspis. This is a natural predator of not only fungus gnats but also Western Flower Thrips. These predators are available to order and come in a 1 litre peat mix.
- Other treatments involve drenching the medium. Aza Max is one of the best drenches on the market because it is not only effective in eradicating the scaridfly larvae but does not cause any stress or damage to the root system.
As the saying goes, prevention is better than cure, so to minimise the risk of encouraging Sciaridfly into your growing area, make sure the medium is not kept too wet
The ideal solution is to use Hypoaspis from an early stage as both a preventative and treatment.
What are the symptoms & treatment for Whitefly?
Whitefly, as the name suggests are small white flies. Generally no more than 1/4cm long they are fairly harmless when in small numbers. A heavy infestation can affect the look and quality of the crop. White-fly leaves a sticky residue on the leaves.
It can be treated with sprays like Aza MaxTM and Mavrik.
What are the symptoms & treatment for Powdery Mildew/Grey Mould?
Poor ventilation and high humidity are two of the main causes of mould in a greenhouse/grow room.
Prevention is better then any cure. Ensure that your growing area has adequate ventilation
Treatment with a diluted solution of Silica used as a spray can help control mould.
Powdery Mildew or Grey Mould is very easy to spot. The main symptoms are small grey or white fury patches on the leaves. It can also affect the stem of the plant.
What are the symptoms & treatment for Pythium/Root Rot?
Pythium thrives in a root zone deprived of oxygen. This is generally caused by over-watering. Pythium discolours the roots. The discolouration progresses from light to dark brown. Eventually the roots will become rotten. The symptoms can also be seen in the leaves. Spots and discolouration turn to necrosis of the leaves and in severe cases the stem can also be affected. It is important to maintain hygiene in the growing environment, and as with all plant diseases prevention is better than cure. Using products like Rhizotonic and Trichoderma in the growing medium help to strengthen the immune system of the plants making them more resistant to infection. Treating pythium is difficult. Systemic fungicides like Fongarid TM are also useful in controlling Pythium.
What are the symptoms & treatment for Collar-rot?
The symptoms are a browning on the base of the plant and eventual rot.
Collar or Stem rot is generally caused by the base of the plant being buried in the medium and the medium remaining constantly wet.
Preventing this is simple. Do not bury the base of the plant in the medium. Secondly do not over water
What are the symptoms & treatment for Botrytis?
Botrytis is also known as bud rot. It affects the flowers and is generally caused by high humidity and poor ventilation. Both day and night time temperature and humidity need to be controlled to avoid this disease.
5. Lighting
What is the Ideal light spectrum for plant growth?
Ideally plants will grow in the range of 400-700nm. This covers a range of the visible light spectrum from blue to red. There are different types of artificial lighting on the market these range from fluorescent to HID lighting and each has their merits. Typically HID lighting is used more widely than fluorescent lighting, particularly if the growing area is large. Plants do not see light the same way we do. Plant available light is commonly referred to as PAR Watts. PAR stands for Photo synthetically Active Radiation. As the name suggests this corresponds to light that most encourages Photosynthesis. Maximum photosynthesis occurs at two peak wavelengths, 435nm (blue) and 675nm (red).
As human beings, we judge light by its brightness, or lumen intensity but the brightest lamp is not necessarily the best for plant growth. The lumen output does, however, provide a guide as to the effectiveness of the lamp.
What are Kelvin and CRI?
Kelvin is a measure of colour temperature. Light output in the range of 380-500nm is considered the daylight spectrum. It is translated as 6500K. This colour temperature is the closest to natural sunlight.
CRI is the acronym for Colour Rendition Index. CRI Is a percentage value of the lamps proximity to natural sunlight. For example, a lamp with a CRI of 65 means that it is 65% close to sunlight. Metal Halide lamps are generally in this range of CRI. High Pressure Sodium Lamps (HPS Lamps) generally have a CRI of 25 to 28, meaning that they are only 25 to 28% as close to sunlight
What types of Fluorescent lights are there and are they a suitable plant light?
T5 Fluorescent lamps
This is a relatively new technology to Australia, though they are very popular in Europe & North America. T5 technology offers 400w MH light output with only half the amount of wattage (approx 216w). Lamps are supplied for either growing or flowering crops. That is, 6400K spectrum & 2700K spectrum.
They are more efficient and offer greater life span than standard fluorescent lamps.
Compact Fluorescent Lamps
There are a number of compact fluorescent lamps on the market. The most well known is the "Spectrum" brand. This is a 130watt compact fluoro that emits approximately 12000 lumens. These lamps are available in 6400Kelvin and 2700Kelvin types. This equates to a "grow" spectrum and a "flower" spectrum. These lamps do not need a ballast. They plug into a standard 10amp power point.
What are High Intensity Discharge (HID) lamps?
There are two main types of HID lamps commonly used as supplementary lighting in either a grow-room or greenhouse. They are Metal Halide (MH) lamps and High Pressure Sodium (HPS) Lamps. Both of these lamp types require the use of an external control gear (ballast) to be ignited. HID lamps were most commonly used for street and warehouse lighting but they have been adapted for horticultural use, particularly in environments where natural sunlight is insufficient.
What are MH (Metal Halide) lamps?
Metal Halide lamps are popular because they have a low colour temperature. Generally MH lamps have a colour temperature of 6500Kelvin. This means that they are a cooler running temperature and also emit a blue-white light that is a closer imitation of sunlight then HPS lamps. This closeness to natural sunlight is expressed as a CRI (Colour Rendering Index). The CRI of most MH lamps is in the range of 60-70. This means that they are 60-70% close to natural sunlight. While this CRI is quite high, MH lamps do not have a very high lumen output. As a result they do not last as long as HPS lamps.
What are HPS (High Pressure Sodium) Lamps?
HPS lamps have do not have as high a CRI as MH lamps but they make up for this by having a higher lumen output and a longer life. The CRI (Colour Rendering Index) of HPS lamps is in the range of 25-28. So, at best a HPS lamp is 28% close to natural sunlight. The colour temperature is around 2700K. This means that the colour emitted is red- orange. This is more like the colour of the sky at around sunset.
What Lamps are best to use?
The best lighting set up should include a balance of both light spectrums. This can be in the form of having both MH and HPS lamps or in having lamps that are designed to provide a balanced spectrum. MH lamps will provide light in the "blue" range (435nm) and HPS lamps will provide light in the "red" range (675nm). There are, however some lamps on the market like the Phillips Son-T-Agro (400w HPS) and Son-T Plus (600w HPS) that have been colour corrected so they provide some light on the "blue" range. This makes them an all round lamp, providing the long life associated with higher lumen output and adequate colour range for plant growth and flowering. MH Lamps can also be "all round" lamps. The Eye MF1000BXU is a frosted MH lamp. It has all the benefits of the "blue" range of light but it also has 20% more "red" then the standard clear MH lamps. Most frosted MH lamps provide this extra colour in the "red" range making them somewhat better for flowering as well as growing crops. The choice as to which is best to use comes down to area and cost.
If you are starting a new system it is worth investing in 400w or 600w HPS lighting.
6. Ventilation and Air Filtration
How important is air flow?
Air flow is arguably one of the most important aspects of a grow room or greenhouse. Not only does it deter mould and fungi developing, but it also provides much needed CO2 for the plants overall growth and development. A well ventilated room will yield more then a room with no ventilation. The only time this is not the case is if the room is controlled with a complete climate control system. In such a room, air-conditioners and CO2 injection system are essential. CO2 is then introduced not by airflow but through a designated injection system. It is important to note that CO2 injection works best in a completely controlled climate. To understand why ventilation is important consider the goal of setting up a greenhouse or grow room. The aim is to mimic the outside environment in a controlled and therefore higher yielding area.
Are oscillating fans needed?
An oscillating fan is necessary for adequate air movement in the room itself. It helps to move warm air in winter and cool air in summer evenly through the plant canopy. Oscillating fans help maintain consistent room temperatures
Why Use a Thermostat?
Thermostats are a very useful tool for controlling both cooling and heating devices in a grow-room or greenhouse. If you want to get the best out of your ventilation and heating system thermostats are a necessary investment.
Do I need Carbon Filters & Fans?
If you are an indoor gardener you may find the need to invest in some kind of air filtration system. The most common systems are carbon filters.
Carbon Filters offer the best air filtration system on the market. Having said this, a carbon filter is only as good as the fan with which it is used. Centrifugal fans are the best types of fans to use with carbon filters. They are designed to be used in high pressure applications, be that drawing through long lengths of duct or drawing through a carbon filter.
Carbon filters are usually of solid heavy construction. One of the better brands on the market is the Can FilterTM, these are made in Holland and are designed to be long lasting. A new brand on the market is called the Odor-SokTM and this is a novel design for a carbon filter. It is made of a carbon impregnated fabric. This makes it much lighter and user friendly then standard carbon filters.
High humidity can affect the longevity of carbon filters as well as the overall yield of the crop so it is important to have good airflow for the sake of the carbon filter and for the overall health of the crop.
How important is Humidity & Temperature?
It is extremely important to monitor & control relative humidity around a hydroponic crop. Relative humidity should be in the range of 50-70% and temperature should be around 30-33degrees Celsius during the day and 18-20degrees at night. Extremes in temperature should be avoided. Temperatures above 35 degrees stop plant development.
High humidity increases the risk of moulds and mildew developing as well as encouraging an irresistible habitat for pests like spider mite & scaridfly.
High humidity also reduces transpiration, which in turn reduces circulation in the plant of essential elements like calcium.
Low humidity, or dry air, can decrease the likelihood of fungal diseases but it also increases transpiration in the plants which can in turn dry the leaves and growing points out excessively. This can produce lack of pollination in tomato crops because the growing point dies. This of course affects the overall harvest of the crop. Increased transpiration in the leaves also affects the fruit already on the plant. Fruit can die or flowers rot because less water is being channelled to the fruit/flower.
7.Carbon Dioxide CO2
What is the relationship between Photosynthesis & CO2?
Carbon dioxide plays a vital role in the process of photosynthesis.
Photosynthesis describes the chemical plant process where the carbon from the carbon dioxide, water and light combine to make sugars. These sugars are the basis for carbohydrates, lignin, proteins, vitamins enzymes and hormones found in plants. In this process Oxygen is released back into the atmosphere.
Photosynthesis takes place in plant leaves and specifically in "chloroplasts". The main parts of a leaf are the upper & lower epidermis, the mesophyll cells, the vascular bundles (veins) and the stomata.
The stomata are pore-like openings on the under side of the leaf. They allow air transfer, i.e. transfer of CO2 and O2, CO2 into the plant and O2 out of the plant.
The Mesophyll cells have chloroplasts and it is in these cells that photosynthesis occurs. Mesophyll cells absorb the carbon dioxide transferred from the surrounding air by the stomata. Carbon combines with water to create sugars that form the basis of plant growth. The by product of this process is Oxygen and this is released back into the atmosphere.
The chemical equation for photosynthesis is;
6CO2 + 6H2O (+ light energy) -? C6H12O6 + 6O2 this translates as 6 carbon molecules and 6 water molecules when exposed to light, turn into one sugar molecule and 6 oxygen molecules.
Chloroplasts are light reactive meaning that they respond to light. CO2, for plants with leaves can only be absorbed during daylight hours. Some plants like Cacti have adapted to absorb CO2 at night. As you can appreciate if conditions are extremely hot and dry with minimal airflow CO2 absorption is lessened.
CO2 is one of the most critical elements in a plants development. CO2 is directly related to the metabolism of the plant and as such an increase of CO2 in the growing area will increase growth rates and ultimately yield. Using CO2 in a greenhouse is not only viable but ultimately environmentally sustainable. A greenhouse in Holland has been built in an industrialised area and harnesses CO2 emitted by local factories into its greenhouse growing area. This kind of forward thinking and ingenuity provides one solution to excess CO2 production in the world today and may be part of the solution for global warming.
For the hobby grower or those not living near industrialised areas, CO2 systems can be purchased. The most basic CO2 system consists of attaching a regulator to a gas bottle which can then be set to a timer. The optimum CO2 level is 1500ppm. Usually the ambient CO2 levels are about 300ppm.
8. Propagation
How do you take Cuttings?
Taking cuttings from plants is a viable way of propagating plant strains, without the expense of buying seeds. You should always take your cutting from the healthiest plants and from the youngest leaf set. Cuttings need only have 2-3 leaves on them for best success. For best results you should use some kind of propagation/seedling box and a heating mat. These are useful because you can control the humidity as well as controlling the root zone temperature. The seedling box is designed with two trays and a vented lid. The vents in the lid allow you to control the humidity and airflow in the box.
The most common medium used for propagation are rockwool cubes, but you can also use jiffy discs. Both of these mediums can also be used for raising seeds. The basic technique for propagating is to soak the rockwool cubes in warm pH adjusted water, squeeze out the excess moisture once the cubes have expanded and place them on a seedling tray. Make a pilot hole in the top of the cube so it is easier to plant the cuttings. The cuttings should, as mentioned above, be taken form the newest and healthiest growth and have no more then 2-3 leaves. The cut, should at a 45 degree angle. Dip the cutting into a cloning gel or powder making sure to scrape off the excess. It is important that only a thin film of gel is placed on the "wound" as too much cloning gel can actually inhibit the roots from developing. Best practice technique for cuttings is to always make sure that whatever gel you use is poured into a separate container or lid and then disposed of once used. Never dip the cutting straight into the bottle as this will contaminate the whole bottle making it less effective for any future cuttings. Once you have applied the gel or powder, place into the rockwool cube. The pilot hole made earlier should make this an easy process. Once planted, place the rockwool cubes on the seedling tray and cover with the vented lid making sure the vents are closed.
The next step is to place in a warm well lit area. Ideally you should have a heating pad, but in summer this is not always necessary. Make sure you have enough light, (if you don't you can purchase a Propagation Light Set, see online shop) and leave the vents closed for the first week, checking the moisture of the cubes periodically. Don't let the cubes dry out, but also do not be tempted to over water them. Over watering is the main reason for failed cuttings. Keep the cube moist but not saturated and you should have good success.
After a week, or when you see the roots staring to develop, open the vents slightly and gradually increase the airflow through the box. Continue opening the vents over the next few days until they are fully open. At this stage roots should be developing well. Once they are fully developed you can remove the lid and gradually acclimatise the cuttings to what will be their new environment, be that outside or in a grow room. It is very important that the transition from cutting stage to transplanting is done gradually to ensure best success. It is no good taking a newly developed cutting and placing them in direct sunlight or artificial light, such light is simply too strong. You are much better off placing them in a sheltered position and gradually increasing the amount of full light/sun they receive.
9. Greenhouse Gardening, Indoor Gardening, Fodder Farms
Gardening Indoors
To understand Gardening Indoors, it is important to understand that in choosing to garden this way, you are attempting to duplicate what occurs in the natural world in a confined space. In the natural world plants need light, air, water and food to survive. In the absence of natural light artificial light must be used. It is extremely important to have your indoor gardening area well designed. A well designed room means that you will have fewer problems with diseases and pests.
Gardening in a Greenhouse
As a DIY project, a simple greenhouse is simply an area outside that gets good sun, and can be covered and protected from wind rain and extremes of hot and cold temperatures. Once the ideal spot is found, greenhouse film and fixtures can be purchased to suit the area. As well as this, entire hobby greenhouses can also be purchased. These hobby greenhouses are made to order and as a result come ready to assemble. For more info see our online shop or email info@newagehydro.com. In a Greenhouse, you are attempting to control the total growing environment of the plants. This includes temperature, light, airflow and of course food. The benefit of gardening in a greenhouse for both the hobby and commercial grower is the ability to grow crops out of season as well as in greater numbers per square metre.
What is a Fodder Farm?
Fodder farms are essentially growing chambers designed to produce fodder for livestock. The main selling point is the efficient use of water and fresh nutrient rich end product.
One of the most efficient fodder production systems on the market today is based on NFT system. 225mm x 80mm channel is used to grow barley or wheat grass for cattle feed.
The expense of the system depends on the number of cattle needing fodder. On average 1kg of Barley will produce 8kg of fodder and harvest is weekly
This kind of system is also suitable for growing wheat grass or sprouts for juices and food.
10. Aquaponics
What is Aquaponics?
Aquaponics is the combination of aquaculture and hydroponics in the one growing system.
Fish are farmed and the waste products are used to feed plants. The waste produced by the fish, is turned into a plant usable nitrate source with the help of nitrifying bacteria belonging to the genus Nitrosomonas and Nitrobacter. Nitrosomonas remove the ammonia from the water that is excreted by the fish and Nitrobacter oxidize toxic "nitrite" to non-toxic "nitrate". This nutrient rich solution feeds the plants and once they have extracted what they need it returns to the fish tanks. It takes about one month for the establishment of the nitrifying bacteria so it is important that the feeding rates are kept low in this period and that the nitrite and ammonia levels are monitored. Or better yet let the system run without plants in this period so as to avoid any toxic build up of ammonia. Once the bacteria have established you will notice increased growth rates.
Any crops can be grown in Aquaponics, the most common and most successful are lettuce and basil. Tomatoes and capsicum can also be grown but it is important that Iron Chelate (Fe-DTPA) and Potassium (this can be in the form of potassium carbonate) are added to the nutrient.
The strength of the nutrient being used to feed the plants is determined by the amount of fish being produced. Fish density should ideally be around 50kg per 1000litres. This is the ratio used by a well established Aquaponics farm in Minnamurra Vic. Murray Cod is being grown at this density and it is used to grow Basil for a commercial market.
Aquaponics provides a model for sustainable agriculture that should be more widely embraced. It has never been more evident then the present day that agricultural practices need to adapt to our climate and changing conditions. Aquaponic gardening provides both fresh vegetables and fresh fish for the table.
If your question hasn't been answered here, feel free to use our contact form or call our FREECALL number at 1800 805 973.
