Hydroponic Basics – a quick explaination

Author: Scott  


BASICS page 1

Hydroponics is a simple method of providing
the minerals found in soil in a mineral solution.

See also our catalogue and information pack download page

There are two main methods used for hydroponics.

1. Passive. No Electricity.

In this method we usually hand water pots or boxes just like soil gardening, but with soil substitutes. This can be very easy and eliminates soil diseases, knowing whether a plant needs fertiliser or what kind of fertiliser. You add the nutrients to tap water and "water" the plants until moist.

To make it automatic, we can also use self watering pots, tanks of nutrients with an automatic valve, or wick systems.

2. Recirculating or pump driven systems

We can use irrigation systems that are amazing. They allow for tremendous growth rates as they maximise a plants potential.

Common methods are:-

Trickle irrigation - trickling nutrients over the roots then allowing them time to use the nutrients before irrigating them again)

roses trickle fed in expanded clay balls

Flood and Drain - flooding the roots then draining them

a tray filled with clay balls is flooded every 2 hours for 15 minutes

Nutrient film technique -growing in pipes/channels

Plants are placed in a shallow (1mm or less) moving stream of nutrients

Aeroponics - spraying roots suspended in the air

roots hang in a chamber and sprayers spray nutrients onto them,
usually for 15 mins, then off for 15 mins

The main ingredients for growing a plant successfully are
  • Light – Either use Sunlight or Artificial light (Agricultural lighting) or a mix of the two.
  • Air – All plants breathe Carbon Dioxide and would run out of air in a small room in a few minutes. At that point, their growth slows and then stops after several hours. This depends on the plant and the size of room. When growing in the outdoors, this is easy. If using a greenhouse, or a indoor growroom, this will require you ensure air exchange – old air removed and fresh air drawn in.
  • Water Availability – Plants are mostly water, like ourselves. WE can go and drink when thirsty. If a plant is thirsty, we must ensure it is able to feed. Over watering will drown the roots and eventually kill the plant. Therefore we must have a root zone that is moist, with oxygen around the roots and moisture for when it is thirsty. Moist means not wet and not dry…. A squeezed out wet sponge for an example is moist, not dry and not wet. This should be used as a quide on when plants roots generally work at their best
  • Nutrient Availability – Nutrients are the minerals plants receive from damp soil. If it is strong, the plants slow or burn. If it is too weak, the plants pale, and become stretched between branches. If the nutrients are not available, deficiencies can develop. pH is the measure of acidity in the nutrients. Most nutrient packs will mix to the correct pH in normal town tap water. Check with a hydroponic store for advice – the pH of good nutrients in our town, the Gold Coast Australia usually sits between 6 and 7 and does not generally need adjustment if changed regularly
  • Temperature – If temperatures fall below 15 degrees celcius, many nutrient elements become less available to the plants and the nutrients or the root zone need to be heated. If temperatures exceed 30 degrees for long periods, the plants require high levels of water and ventilation to keep it from undergoing stress. In both cases speaking to an advisor will help you make the right decisions about the best solution.

Growing MediaPerlite

– White granule manufactured in a kiln. It is free from any disease because of the heating process as it is made. It holds around the same amount of water as soil, but more difficult to over water. It suits hand watering in normal pots and saucers, wick systems and Automatic Valve systems.Expanded Clay – Terracotta coloured clay ball made in a kiln. Like perlite, it is sterile, and holds water for around 1- 4 hours. It is most suitable for Trickle feeding, and flood and drain systems.No media – Aeroponics – Aeroponics usually use small netted pots filled with clay balls for support, but the roots generally are in the air where the nutrient can be sprayed onto them.

No Media – Nutrient Film technique – The roots lie in the channels, and soak up nutrient from the flowing stream. The roots are never under water, and get their oxygen from the channel. (If submerged, roots may rot)

Rockwool – Spun from liquid rock, this product looks like insulation. It is similar and made from horticultural components. (insulation has fire retardant chemicals and water repellents so are unsuitable for Hydroponics) Used for propagation, and as slabs this is popular in Europe, and is used mostly for Hobby growers in Australia.

Vermiculite – Vermiculite is a highly absorbent material able to hold around 200 times its own weight in water. It is added to Perlite and soil mixes if the mix has to hold water longer than normal. Note Perlites that hold water poorly are generally cheap and grey, not white. Look for a White perlite such as Chillego brand in Australia.

Others: Absorbastone is mined in Queensland and is similar to Versarock. Both have failed to catch on. Scoria is popular in New Zealand and Victoria, but limited availability makes it difficult to buy in other states. Coconut fibre comes in bricks and has proved promising, however, take care as I have had some problems. Use a Coco specific nutrient, as it does make a difference, and rinse really well. If fungus attacks on plants this may be coco related and use Microkill ( a friendly bacteria)


We have a range of nutrients. Most of the brands get more expensive as they get more effective. They include Powergro, General Hydroponics, Coco Feed, Optimum, Ozimagic, Europonic, as well as others. As a hobby grower, most people start with our own inexpensive brand, and move up to others if they wish to see more advanced results. Prices range and I do not wish to spend too much time on prices here, however, cheaper powders are available as well, but you get what you pay for. Commercial Nutrients are made for the farmer, and come under a different price structure.

Most brands come in an A and B pack, where the A part contains the main calcium and iron, and the B part which contains mostly everything else. The calcium has to be kept separate in the concentrated form to keep it from solidifying. All you need to do is add to every litre of water, 5ml of A, stir the liquid and then add 5ml of B. This will give you a nutrient solution that is the right strength for most applications. If mixed with most town water supplies the pH will be around 6-6.8 which is fine if you have no pH testing. We suggest testing the nutrient is around this range is good for peace of mind, but if you develop any problems with the plants have the pH checked at a Hydroponic or Pool shop. You should be able to get a simple test kit under $10 at a Hydroponic Shop, or a Pet store or Pool shop.

LightingMany people enjoy excellent growing all year long under grow lighting. You can use the lighting to get faster growth (18 hours per day of light), or grow in areas that have insufficient light. Examples might beFluorescent – Useful for seed raising and cuttings. Also used when some light is available, such as a living room, and the fluorescent can be used to enhance growth by running for 18 hours per day. Can be less effective for larger plants. From $50 Our BIG FLURO CFL Veggie lights – for use where sunlight is not providing plant growth and plants need a boost. 125Watt lamp $65* kit $170* (*check prices)
AGRO type lights – These replace sunlight and can control the time plants flower or fruit by reducing the length of the day.

A 400 Watt covers around 1m x 1m,
costs around $200-$250* (*call for latest specials)

A 600 Watt covers around 1.5m x 1.5m,
costs around $260-300*

A 1000W Super-Gro metal halide covers around 1.6×1.6m, costs around $350-$400* (*call for latest specials)

A 1000W HPS agro covers around 1.8m x 1.8m.costs around$400-480* (*call for latest specials)

For lighting advice contact us on the site, call us on

07 5527 4155 or look at our information page

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