You will need to understand and apply the basics of water quality management, a detailed knowledge of the biology of your cultured species, feeding schedules, system design, construction and management and ability to clean and maintain all the equipment that you are going to use. Good record keeping is another skill required.

You grow the animals that are required by your market. You will need to supply them to your buyer when and where he wants them, in the sizes and quantities he requires, when he requires them. If the buyer is solvent then he may pay you for your product when you want to be paid. However expect to have to chase the buyer for your money.

You will need to grow the animals for a lower cost than you sell them - otherwise you will be going backwards financially.

Good idea - as a general rule you will need to stock the dam at the beginning of the season with ten juvenile yabbies per square meter. At the end of the season you should be able to harvest three yabbies per square meter.

The average size might be 75 grams. Farm gate prices are about $ 12.00 per kilogram so you will gross (3 x 0.075 x 12)= $ 2.70 per square meter of dam. You will need 55,555 square meters of dam to get your $ 150,000 gross per year - that is 5.55 hectares of ponds. ( you will also need 555,000 yabbies at the start of the season.

Five hectares of yabby ponds will attract the native herons and cormorants - don't forget that these birds are protected - no shooting - so you might need to look at some protective netting to stop your yabbies being taken. (There are also a lot of walking upright two legged predators so you may need a good dog and electric fence)

Depends on how simple and what you are trying to achieve. If you want to grow out a species then you will need sufficient animals/plants so that you can gain experience with the production of the species and learn how to manage your system.

As a rough guide about $ 3,000 should allow you to purchase water quality measuring equipment, small tank, pump,filter, biofilter, water heater, aerator and fifty small animals. You need to plan on growing the animals to market size and doing this several times before spending any more money - who knows you may find that it is all far to hard and you would rather be playing cricket with your mates !!!

Air and water are in a tube submerged in water and as this mixture is less dense than the water surrounding the tube the pressure difference forces the air/water mixture to rise inside the tube.

The one thing that will save a tank full of aquatic animals when the power goes off is injecting oxygen into the water.

Remember that in water 100 percent oxygen saturation is about 10 milligrams of oxygen per litre of water - compare this to air which contains nearly 20% oxygen. In most commercially stocked systems if the power goes off for 15 minutes it is likely that some of the animals will start expiring.

An oxygen bottle with a regulator and flow meter connected to airstones or diffusers in the tanks can be set to deliver the oxygen only when the electic power goes off. A special solenoid valve in the line is normally kept closed whilst electic power is on. If the power goes off the solenoid valve opens and oxygen leaves the oxygen tank and starts bubbling throuth the airstones or diffusers. When the power comes on again the solenoid is held closed and the oxygen flow stops.

Place a airstone in the bottom of your tank and position a funnel with a tube extending the funnel stalk over the airstone so that the airbubbles are trapped in the funnel and forced up the stalk. The airbubbles and water mixture will rise up the extension of the funnel stalk. If the top end of the funnels stalk is above the water level the air-bubble and water mixture will rise above the water level.

The extension to the funnel stalk should have a ratio of 1 : 50 internal diameter of tube to length of tube. The maximum lift will be half the submerged length of the tube.

Depends upon the minimum income you require. Most aquaculture operations require a 24 hour a day committment and for seven days a week. Generally mains electric power is required and you will need a backup generator. The food cost for the aquatic animals will be a major cost, then electricity, depreciation, fingerlings or seed stock. If you work on an average price of $ 10.00 per kilogram for what you produce you will need to produce 15 tonnes per year to gross $ 150,000 - with no accidents or foul-ups you might get $ 15,000 for your efforts after all costs have been deducted. (not much for being on call 24 hours a day, seven days a week)

Yes, but it will take a long time to get up to a profitable size.

Yes - generally the species that are native to your area will be easier to grow - they will be in plentiful supply, used to the local climate and water quality conditions and have a good genetic pool to draw from.

Hydroponics is a method of growing plants without soil.

Soladome has a number of simple systems from $1.00 to get you started.

The plants are grown in a sterile material called a medium - some of the popular mediums are Versarock, Perlite, Vermiculite, Growool, Expanded clay, quartz gravel, dolomite.

A fertiliser especially made for hydroponic growing is mixed with water and fed to the plants.

The plant containers can be placed at a convenient height to avoid bending down and because there is no soil then there are no soil-bourne diseases or pests to worry about. There are fewer weeds and because the mediums are generally well drained the roots have plenty of air for healthy root development.

All sorts of containers can be used to hold the medium and plant. All your old plant pots can be adapted for use in a simple system. There are automatic feeding and watering systems to suit a variety of climatic situations.

Although there has been a lot of recent interest in hydroponics this method of growing dates back to 600 BC wuth the Hanging Gardens of Babylon located in what is now southern Iraq. King Nebuchadrezzar The Second built a series of hanging and terraced gardens to cosole his wife and remind her of her undulating and lush homeland.

pH refers to the relative concentration of H+ ions in solution. The numerical value of the pH is the negative of the exponent of the molar concentration. Thus low pH values indicate high concentrations of H+ ions (acid), and high pH values indicate low concentrations...

Hoagland & Arnon in U.S.A. in 1938 developed a nutrient solution for laboratory research purposes and their formula is listed below. To the right of their formulation is the general range of nutrient elements used by plants...

Potassium
Lower leaves are mottled. Yellowing and death of tips and edges of older leaves.

Nitrogen
The plant is light in colour and weak and spindly. small leaves with the lower leaves light green. some plants ( strawberries ) show a reddening of the older leaves.

Too much N/NO3 - plants uncontrollably vigorous
Too much N/NH4 damage to roots and collapse of plant

Phosphorous
leaves are unusually dark and may become purple. Lower leaves may turn yellow between the veins. plants are stunted

Calcium
Tips of young leaves and growing points die. blossom end rot of tomatoes.

Magnesium
Margins of lower leaves curl. Yellow areas may appear between veins

Iron
Younger leaves yellow between veins but yellowing spreads to to whole leaf and the leaves die from the edges.

Manganese
Upper leaves become yellow between the veins and in severe cases dead spots form. the veins remain green.

Boron
Plants become brittle and growing tips may die.

Drought conditions or high salinity can cause the edges of the leaves to burn and in severe cases leaves will drop from the plant.

A Suggested reading list

Title		Author		Publisher		ISBN number		Approx price (Australian$)
	Hydroponics Simplified		Tom Colcheedas		T Colcheedas				$ 7.90
	Hydroponic Gardening		Stephen Carruthers		Lothian		0 85091 557 0		$ 14.75
	Hydroponics For Everybody		Dr. Struan Sutherlamd				0 908090 94 3		$ 22.75
	Hydroponic Gardening in Australia		J. Romer		Reed Books Pty. Ltd.		0 7301 0098 7		$ 24.95
	Simple Hydroponics for Australian Home Gardeners		A.C. Sundstrom		Thomas Nelson Aust. Ltd.				$25.75
	Hydroponic Gardening in Australia		Lon Dalton & Robin Smith		Lothian Press				$ 33.00
	Basic Hydroponics for the do-it-yourselfer		M. Edward Muckle		Growers Press Inc		0 921981 40 6		$ 32.50
	Growing Herbs		John Mason		Kangaroo Press		0 86417 552 3		$ 19.95
	Advanced Guide To Hydroponics		James Sholto Douglas		Pelham Books		0 7207 1571 7
	Gardening Indoors		George F. Van Patten		Van Patten Publishing		1-878823-11-6		$ 44.95
	Practical Hydroponics & Greenhouses				Casper Publications Pty. Ltd.		1321-8727		bi-monthly $ 5.95

For more information on commercial type operations
	Hydroponic Crop Production		Joe Romer		Kangaroo Press		0 86417 527 2		$ 35.90
	A Practical Guide to NFT				Johima Books		0 9513519 0 7		$ 69.00
	Commercial Hydroponics				Kangaroo Press				$ 35.90
	Hydroponic Food Production		Howard M. Resh, Ph.D.		Woodbridge Press Santa Barbara CA		0 N88007 171 0		$ 59.95
	Commercial Hydroponics in Australia (A Guide For Growers)		Australian Hydroponic Association Inc				0 646 15525 3		$ 49.95
	Master Guide To Planning Profitable Hydroponic and S/CEA Operations Worldwide		Adam J. Savage Ph.D (1987)		International Centre for Special Studies Honolulu Hawaii				$ 79.00
	Proceedings of the Introductory South Pacific Hydroponic Conference ( 1990 )		Australian Hydroponic Association Inc for Special Studies						$49.95
	Australian Hydroponic Conference February 1993		Australian Hydroponic Association Inc				0 646 18970 0		$ 49.95
	Australian Hydroponic Conference July 1995		Australian Hydroponic Association Inc				0 646 18970 0		$ 49.95

You will need the following

1. A container, old plant pot, plastic ice-cream container, in fact almost anything that is not metal.

2. A medium for the plants to grow in. Perlite, clay balls, coarse washed river gravel or versarock. The medium should not contain any organic bits & pieces.

3. A balanced hydroponic nutrient solution.

And of course some seeds and plants.

One of the easiest methods of starting is to take a standard plastic garden pot of 10 or 15 centimeters ( 4 to 6 inches ) and sit it in a plastic saucer or old ice-cream container. Wash the medium to be used and then put it in the pot. Plant the seed in the medium at a depth equal to twice the diameter of the seed. Water daily with rain water or spring water and keep a little water in the saucer.

Keep the pot in a sunny warm position. When the seed has germinated and the seedling is 10 days old start addding the balanced hydroponic nutrient to the water you put on the medium. Use the nutrient at half strength for a week and then gradually increase to full strength over the next week. Make sure that there is always a little liquid in the saucer to keep the medium damp.

If you buy a punnet of seedlings from a plant nursery they can be converted to hydroponics as follows. You will need two containers each three times larger than the punnet of seedlings.

1. Put warm water in both containers and put the punnet in the first container

2. Gently ease the seedlings out of the punnet by pushing up on the underside of the punnet. Use fingers and thumb to knead soil so seedlings separate from each other.

3. Place seedlings still with some soil attached to their roots into the second container.

4. Continue to soak and gently knead soil to remove from roots. Wash out first container and refill with warm water. Transfer seedlings to the first container and continue to remove as much soil as possible - if necessary by repeating the move to cleaner warm water.

5. When most of the soil is removed place the hydroponic pot half filled with medium in one of the washing containers, add water until the lip of the pot is just under water. Gently hold the seedling in the middle of the pot whilst you add more medium to settle the roots into position. When the pot is full of medium lift the pot out of the water and stand it in a saucer.

6. Keep the young plant warm but out of direct sunlight for a few days and feed half strength nutrient making sure that the medium is kept damp at all times. After about a week you should be able to increase the nutrient to full strength over a few days and move the plant to your chosen location.

First a little physics is required

P = E/t
( P in watts, E in Joules, t in seconds )

Calculate the change in heat of the substance

delta h = C*m*delta T
( h in Joules, C specific heat capacity JK-1 g-1,
m mass in gms, T in degrees K
Cwater = 4.2 JK-1 g-1)

Assuming no energy losses by conductance from fluid to surroundings and using a 250 watt heater in a 200 litre reservoir with the water at 12 degrees Centigrade how long will the heater have to be on to raise the water to 22 degrees Centigrade ? ...

Getting started

KEEP IT SIMPLE - Use readily available bits & pieces and keep the moving parts to a minimum

1. A container of some sort - milk cartons, ice cream containers, plastic bottles and bags - in fact almost any non metallic container will do.

2. An inorganic medium - perlite, rockwool, clay balls, versarock, or a well washed coarse river gravel to put into the container.

3. Make up a balanced nutrient solution by either mixing a hydroponic nutrient powder in clean rain water or by putting a small amount of concentrated liquid hydroponic nutrient into water. Use the mixed up solution to keep the medium in the container wet.

Little seed starter kits suitable for hydroponics are available costing from $2.00

Mediums cost from 25 cents per litre upwards

Nutrients cost varies from 1/2 a cent to 9 cents per litre of working strength solution

Chose a location that will suit the plants to be grown to give good light, warmth and shelter from strong draughts.

Mount the gulley so that it is horizontal and the drain end is just higher than the top of the waste bucket. Make sure that the holes in the gulley are facing up. Set up the reservoir so that the base of the reservoir is 30 cm above the drip-in hole of the gulley...

Cloning: The art of producing an identical copy of an existing plant. This can be done by tissue culture or more often by taking part of the living mother plant and growing it away from the parent.

First prepare the medium to receive the clone. One of the easiest methods is to use wrapped rockwool cubes. Soak the cubes in a half strength nutrient solution that has been made up using spring water. Plan on putting the cubes in a tray or trough to keep the bases wet...

Garlic spray, Red spider mite spray, Pesticide spray, Fungicide spray, Onion spray, Fungicide spray 2, Rhubarb spray, Chive spray, Cockroach killer, Insecticidal herbs for the garden ...

Umbelliferae ( fragrant or aromatic ) crops should be in a different hydroponic system from other plants this family includes parsley, fennel, sweet fennel, parsnip, carrot, corriander and dill. Onion family members must also be grown apart from other crops. Most other common herbs and vegetables appear to be compatible...

Some different types of soilless cultivation.

Aeroponics - the roots of the plants are in an environment saturated with a mist of nutrient solution.

Water culture - The roots of the plants are submerged in a nutrient solution.

Sand culture - plant roots are grown in solid particles with a diameter less than 3mm.

Gravel culture - plant roots are grown in solid particles with a diameter greater than 3mm.

Rockwool culture - plant roots grown in rockwool or similar inorganic compounds.

NFT or nutrient film technique where the roots lie in a shallow channel and a thin film of nutrient solution flows over the roots.