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Hydroponics

WHAT IS HYDROPONICS?

Hydroponics is an easy process which helps plants grow fast by making use of water and essential mineral nutrients. Hydroponics is actually a branch of agriculture where you can cultivate plants without soil.

With hydroponic growth, you have increased control over growing conditions which makes it easier to provide the best possible environment for plants, leading to better quality produce and higher yields. Fast-growing, healthy plants grown using hydroponic methods are more resistant to pests and diseases. You will also notice improved flavour and texture in hydroponically grown fruits and vegetables.

WHY GROW HYDROPONICALLY?

This is an extract from ACS Distance Education who have online courses on a number of different subjects including hydroponics.

http://www.acsedu.com/courses/

Hydroponic growing has been used commercially since 1970 and it is growing rapidly in the home gardening sector because it is an environmentally friendly way of growing fresh fruit and vegetables. Another benefit for the home gardener is the fact that an excellent supply of fresh produce can be harvested from a small growing space.

Another factor that many do not realise is the fact that hydroponic growing is an intensive form of gardening with many plants being ready to use in half the time than those grown in the garden soil.

There are endless advantages to growing hydroponically. For instance up to 95% less water is used, and denser planting means less space is required. Plants can be grown in arid areas and indoors with correct lighting. Plants will reach maturity much earlier, there are significantly less pests and diseases, and less maintenance is required.

Hydroponic systems are improving all the time and they can be set up from simple systems, such as a foam box, to more complicated systems such as vertical gardens. Like anything new, it takes some time to learn the basics, but once you have there are definitely a lot of benefits.

HYDROPONIC EQUIPMENT

We stock a full range of hydroponic equipment, nutrients, lights, shades, ballasts, pots, tubs, tubing, plumbing, cloning powder and gels, meters and pH adjusters. For the laid back grower, we have AutoPots which don’t have pumps, but rely on gravity and the Smart Valve to feed the plants. These are great for anyone starting out.

Products we stock include Canna nutrient, Canna PK 13-14, Canna Cannazym, Canna Rhizotonic, Canna Boost, Rock Nutrient, Rock Resinator, Rock Supercharge, Rock Super Growth, Flairform nutrients, Growth Technology, Ionic Nutrients, AutoPot Nutrients, pest control products, fungal products and other root and bloom additives.

HYDROPONIC SYSTEMS

HYDROPONIC EQUIPMENT

Nutrient solution flows continuously along a series of channels (e.g. PVC pipe or guttering). Plant roots dangle in the flowing water and air, while the plant tops are supported above (e.g. tied to trellis, or sitting on a platform of plastic mesh). The channels are sometimes filled with coarse sand or stones, but water absorbing material such as perlite should be avoided as it can cause root rots.

Suitable plants to grow in NFT: tomatoes, cucumber, lettuce, beans, broccoli, cabbage, cauliflower, celery, chicory, corn, eggplant, capsicum, okra, herbs, spinach, strawberry, pepino, snapdragon, stock, and chrysanthemum. Channels filled with non-absorbent plastic beads have been found to be very good for propagating cuttings.

Unsuitable plants: bulbs, roses, indoor plants.

Possible problems: A power failure can stop the flow of solution and result in plant death very quickly. If the series of channels are not calculated properly, some plants can end up with more or less nutrient and water than others. Solution which is exposed to light can grow green slime (i.e. algae). This may not harm the plants, but it can clog up the pipes and affect the flow of nutrient solution.

GRAVEL BED SYSTEMS

These are a raised bed or boxed structure which is filled with a coarse sand or stone (e.g. aquarium sand, washed granitic sand, blue metal chips or scoria stone). Nutrient solution can be applied in various ways:

  • Flooding then draining off the excess
  • By a drip irrigation system
  • Collecting and reusing the excess or allowing it to be lost (run to waste)

Suitable plants to grow: Jerusalem artichoke, asparagus, garlic, leek, lettuce, melons, onions, potato, cabbage, cauliflower, broccoli, Brussels sprouts, pea, radish, tomato, strawberry, herbs, cut flower bulbs, carnation, chrysanthemum, and pineapple.

Unsuitable plants: root vegetables such as carrots and parsnips are more difficult.

Possible problems: If the medium used is poorly drained, root rots can occur. Avoid too much vermiculite in any mix. Irrigations should not be too frequent in cool weather. (Gravel beds in Melbourne may only need winter irrigations every 1 to 4 weeks).

ROCKWOOL SLABS

Rockwool is an absorbent sponge-like material made by spinning molten rock into fine fibres. It is very lightweight, being made up of more than 95% air space, and has the ability to absorb and hold more nutrient solution than other materials, while still also retaining lots of air around the roots.

Seeds or cuttings can be started in rockwool, and the roots simply grow amongst the fibres. Nutrient solution can be applied simply with a watering can, or through a drip irrigation system. Overwatering is almost impossible.

Suitable plants to grow: Jerusalem artichoke, lettuce, melons, onions, capsicum, cucumber, eggplant, zucchini, pumpkin, tomato, strawberry, carnations, chrysanthemum, rose, and gerbera.

Unsuitable plants: root crops.

Possible problems: Large plants become top-heavy and need trellising. Algae can grow on the rockwool surface, then die leaving a water-resistant coating on the surface (avoid by keeping as much of the surface as possible protected from light; this is done by using wrapped slabs).

Rockwool slabs are generally not reusable.

PERLITE GROBAGS

Perlite in a non-transparent bag, usually plastic. After wetting the perlite with nutrient solution, plants can be planted direct into the medium. Nutrient is applied usually through a drip irrigation system, but can also be applied manually. Commercial kits are available in store.

Suitable plants to grow: globe or Jerusalem artichoke, leek, lettuce, tomato, capsicum, cucumber, Gerbera, carnations, and chrysanthemum. Most other crop plants can be grown successfully in a home situation.

Unsuitable plants: root crops.

Possible problems: Perlite can be dusty, but wetting before use can minimise this. Algae can grow on surfaces exposed to light. Sprinkle coarse sand on any exposed surfaces to stop this from happening.

AEROPONIC SYSTEMS

Plants are supported on something like a platform or grid, with roots dangling through openings into an enclosed chamber below. Nutrient solution is periodically sprayed in the chamber to fertilise and water. Being enclosed in a chamber, the humidity always remains high around the roots preventing drying out.

Suitable plants to grow: lettuce, tomato, parsley, silver beet, celery, cabbage, beans, strawberries, melons, and cucumbers.

Unsuitable plants: root vegetables.

Possible problems: If the pumps break down, roots can dry out very quickly.

CAPILLARY-FED BOXES

Water and nutrients are drawn by capillary action from an outer well (e.g. bucket) which is topped up as required. For example, terracotta pots filled with gravel stood inside a bucket containing nutrient solution.

Suitable plants to grow: Many indoor plants (e.g. African violet, Aphelandra, Dieffenbachia, Dracaena, Ficus, ferns, palms and so on).

Possible problems: Root rot can occur if the level of nutrient solution is kept too high, particularly in cooler weather. Allowing nutrient solution to drop too low in hot weather is also dangerous.

NUTRIENTS

Nutrients are one of the most confusing aspects of hydroponic culture. There are so many to choose from, and you could even decide to make your own. For the commercial grower, the choice of what to use can be critical. However, for the hobbyist who is using one standard nutrient and growing a variety of different plants, any “general” properly formulated nutrient will probably work as well as another.

To achieve the ultimate with hydroponics, you need to recognise that every plant variety has different needs at each and every stage of its growth. You can cater for these needs if you’re growing an acre of one crop, but if you’re growing three tomato plants, six strawberries and a dozen lettuces all in one system, you must compromise and use a fertiliser which is generally acceptable to all three plants.

WHERE TO PUT A HYDROPONIC SYSTEM

Remember plants are no different in hydroponics than in soil when considering the need for light, temperature, pest control, ventilation and so on. Many people grow hydroponic gardens in small courtyards or otherwise unused places such as along the narrow side of a house. Hydroponics can be a great, space-saving way to make use of such areas, but if these areas are poorly ventilated, or are dark, this can restrict what can be grown there.

Hydroponic beds or channels can be mounted on a wall, set above paving or even set up on a timber veranda. They are ideal in a greenhouse or a well-lit shed, perhaps under a skylight. Many types of systems are able to be moved if you want to change the garden around, and some can even be put on wheels to allow you to move them to a better part of the garden in different seasons.

HYDROPONIC TERMINOLOGY

Solid Media – inert material which the plant roots grow amongst (e.g. sand, perlite, rock wool, scoria, ceramic chips etc.).

Automatic System – where nutrient solution is applied under water pressure automatically using some form of irrigation system (e.g. pumps).

Manual System – where nutrient solution is applied manually (e.g. by lifting a container of nutrient solution above the plants and allowing gravity to apply the solution, or using capillary action whereby the solution soaks up into the media from below the plants via absorbent material).

Nutrient Solution – a carefully balanced mixture of nutrient fertilisers and water which will give the plant all the nutrition it needs in the most appropriate concentration for the plants being grown.

Run to Waste – where any excess nutrient is drained out of the system and lost. Also called an Open System.

Closed System – where waste products cannot escape. The system is totally closed to the outside.

 

More Information:

Hydroponics courses http://www.acs.edu.au/Courses/Hydroponics-courses.aspx

Online courses in gardening, landscaping and more http://www.acseduonline.com

Mail order books and videos on gardening, landscaping and more http://www.acsbookshop.com

Articles, courses and information http://www.acsgarden.com

AQUAPONICS

Having always had an interest in fish, we progressed into aquaculture when farming in the 1990s and ran the facility1408675890346 until we sold the farm in 2004. When we began fish farming, the aquaculture industry was in early development and there was very little information available. With Bruce Sambell from Ausyfish in Childers, we formed the Aquaculture Association of Queensland.

The association helped new growers progress into fish farming through on-farm meetings and our annual conference. It was through one of our conferences in the early ‘90s that Geoff Wilson from Brisbane was promoting this new backyard fish farming combined with growing veggies called aquaponics, but in those early years of fish farming it didn’t progress to the stage it is at now. We now stock fingerling.

WHAT IS AQUAPONICS?

Aquaponics is a sustainable food production system that combines traditional aquaculture (raising aquatic animals such as fish, crayfish or prawns in tanks) with hydroponics (cultivating plants in water) in a symbiotic environment.

In the aquaculture, effluents accumulate in the water, increasing toxicity for the fish. To solve this, the water is fed to a hydroponic system where the by-products from the aquaculture are filtered out by the plants, after which the cleansed water is recirculated back to the animals.

SYSTEMS

Aquaponics is a sustainable food production system that combines traditional aquaculture (raising aquatic animals such as fish, crayfish or prawns in tanks) with hydroponics (cultivating plants in water) in a symbiotic environment.

In the aquaculture, effluents accumulate in the water, increasing toxicity for the fish. To solve this, the water is fed to a hydroponic system where the by-products from the aquaculture are filtered out by the plants, after which the cleansed water is recirculated back to the animals.

SPECIES

Another frequently asked question is what fish species can be grown. It depends on what location and climate you live in. Barramundi, for example, do not like temperatures below 15 degrees celsius. The two species which can handle a range of temperatures are the silver perch and the Barcoo grunter or jade perch.

SILVER PERCH

Silver perch are an excellent pond culture fish, but not as good in tanks compared to other species. We have grown silver perch in our aquaponics tank in the shop to over one kilo. On the downside, silvers will grow to size but at a slower rate. On the plus side, silver perch will tolerate low temperatures quite well.

SLEEPY COD

Sleepy cod are an excellent table fish. This species is a little more challenging because of the need to keep them crowded, and feeding. They need warm water.

CATFISH

Catfish (Tandanus tandanus) are a very useful fish to include in your system. They are scavengers and are generally bottom feeders. They will eat any food that is left by your perch and help to clean up the droppings from your perch, and in all the little spots where waste can hide and build up.

A catfish’ temperature tolerance is wide. Anything your other fish can handle, they will be happy with. You only need a few in each tank. Not much information is available on their growth rates, but with more people adding a few to their systems, it won’t take long to build up some knowledge.

The big bonus is that they are excellent on the table with white and delicate flesh. When you are ready to eat them, just humanely dispatch them. Before gutting and heading them, pour hot water over the skin. The skin can then easily be peeled off. The protective coating of mucus will not be slippery once the hot water has been applied. Cook them a bit longer than perch to produce the best texture. Undercooked, they can be a bit too moist.

MURRAY COD

Murray cod are a fast-growing fish. Compared to silver perch and jade perch, which have a genetic potential of only a few kilos, Murray cod have the genetic potential to reach around 50 kilos! This means a 1Kg fish IS JUST A BABY! They also have the best temperature range for survival and growing. They are only suited to grow out in tanks as they need to be kept at high density to supress territorial behaviour. They are PERFECT table fish!

JADE PERCH

Jade perch, on the other hand, are an IDEAL fish for aquaponics. One thing to watch out for with jade perch is to have evenly grown fingerlings as (like barramundi) they do get a taste for their mates. Overall, the jades are the hardest species suitable for tanks, and are the perfect beginners’ fish. They are fast-growing and aggressive in feeding and against other species. On the downside, they prefer warm water and will slow down feeding with water under 18 degrees and can stop eating completely with cold winter water.

STOCKING DENSITIES

Just how many fish you choose to put into a new system is governed by so many factors. Fish species, volume of grow beds attached, through-put of water, how well you manage the system, how big you allow them to grow before harvest, and so on.

Personally, I purchase one fish per 10 litres of water in my fish tank, sometimes a few more if the mood takes me. Right now I have 300 fingerlings in a 925 litre tank. They will be split up soon into two tanks, then later into three tanks, and so on.

Having learned my craft by hard experience, I am very happy to stand by this formula without fear. They will grow well and healthy, and will all reach my dinner table in due course.

Whether one expresses stocking density in kg or number of fish is a moot point. Some will express the stocking density in number of fish per cubic metre or in kg per cubic metre. If you wanted to apply some formula to the exercise then the stocking density would be expressed in kg per m3.

Most householders are content to know the answer to the “how many fish” question. To express an upper stocking density for home systems as a kg measurement, then 30 to 40Kg per 1000 litre fish tank volume is a good manageable number for a well found home-based system.

GROWTH RATES

Another important variable is how much food will be put into the system. Most beginners tend to overfeed their fish. Overfeeding puts extra load on the system and is just a waste of food.

Let’s examine how it works.

100 new jade perch or silver perch or tilapia fingerlings would be lucky to weigh one kg, so at the beginning we could say we have stocked our tank to 1kg per 1000 litres.

Obviously fish grow (well, we hope they will) and at some time that 100 fish may well collectively weigh 30 or 40Kg. When that day arrives, start the BBQ immediately!

If you had 100 fish weighing 300g each, you will then have a total of 30Kg of live fish in the tank.

If you start your aquaponics system with a population of one fish per 10 litres of water then you need to understand that you must commence harvesting the bigger fish as soon as they are ready.

Most species of fish will not always grow at the same rate and therefore the bigger ones will be harvested out as soon as they are ready. Not only will we keep the overall weight of fish in the tank in hand, but the actual number of fish will diminish (because we are eating them in case anyone is wondering how we will do this).

Variable fish growth rates are actually a really good feature for the home grower. The home grower can gradually harvest their tank of fish over several months rather than having to have a total harvest in one day. As they harvest two or three of the bigger fish a week, the smaller ones grow and the numbers in the tank diminish.

It is a reasonable expectation that no-one will grow that 100 fish out to become 5kg monsters, or even one kilo fish, and have them all in the same tank all at the same size.

Don’t try to grow them out to one or two kg fish because you have in your mind the same regulated minimum size limits as for wild caught fish. These are your own fish, you can harvest them whenever you want!

Even fast-growing species such as barramundi and trout have growth rate differences, but not to the same extent as, say, jade and silver perch. If you are intending to grow out one of these species you will need to adjust your initial stocking numbers down accordingly. Start with only twenty or thirty fish per one thousand litres.

Then there is the opposite of that – I call it the “bloke” effect. Some “blokes”, when starting out, get excited about the idea of being able to go and harvest a fish whenever the mood takes so they decide to double the number of fish to two or even three fish per thousand litres. Don’t do it!

Those same “blokes” often have an “I must have the biggest fish” phobia. This is a bad combination which will lead to difficulty.
You must be prepared to manage the system well, and harvest as soon as they are ready. You will have a wonderful result. Have fun as you utilise aquaponics to move towards self-sustainability.

FISH

We sell fingerlings for farm dams or aquaponic systems. We have silver perch, jade perch, and Australian bass in-store during the breeding season, and can order in golden perch, sleepy and Murray cod.

FEED

We stock Ridley Aquafeed, and this can be purchased in kilo or 25Kg bag lots. Feeds come in a variety of sizes including dust, starter crumble, 2mm, 3mm, 4mm, 6mm and 10mm barra.