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What is Hydroponics?What is hydroponics?

Hydroponics, by definition, is a method of growing plants in a water based, nutrient rich solution. Hydroponics does not use soil, instead the root system is supported using an inert medium such as perlite, rockwool, clay pellets, peat moss, or vermiculite. The basic premise behind hydroponics is to allow the plants roots to come in direct contact with the nutrient solution, while also having access to oxygen, which is essential for proper growth.

The type of nutrient that must be used depends on the type of system. An important distinction can also be made between open and closed systems.

In open cultivation systems (run to waste) substrate is continuously supplied with fresh nutrients, while the old is removed from the substrate by the drainage system. In a closed or re-circulating system the nutrients aren’t removed by the drainage system, it is collected and supplied to the plants again. This is particularly useful if no substrate is being used in cultivation or if the substrate retains relatively little moisture (baked clay pebbles and perlite).

It is very important in hydroponic cultivation systems that the nutrient solution contains all the necessary elements that the plant needs in the correct proportions. The most suitable type of system depends on the grower’s preference and experience.



The word hydroponics comes from the Greek words hydro (water) and ponos (to work) and literally means ‘water work’. The first hydroponic systems come from antiquity. In fact, The Hanging Gardens of Babylon, and the floating gardens of the Aztecs in Mexico were the first hydroponic systems. Thanks to the continuous flooding it was possible to cultivate food the whole year round.

The basis for modern hydroponic systems was laid after the experiments that took place from 1895-1865 done by German scientists Von Sachs and Knop. They discovered that plants needed certain nutritional elements to develop.

The first successful hydroponic systems were developed in the thirties by Dr. Gericke in the American state of California. During the Second World War these systems were adapted to provide American soldiers with fresh vegetables. The first hydroponic systems were adapted for commercial purposes for the production of vegetables and flowers in the seventies and eighties.


Open systems (run-to-waste) Closed systems (recirculating)
Pro Easier to control as the plant receives fresh
made nutrient continuously.Also suitable for low quality tap water (EC of
0,75 or higher).
No systems drain necessary for used
nutrients.Lots of air available for the roots when the
proper substrate is used.
Contra No systems drain necessary for used
Diseases can spread trough the entire system by recirculating nutrients.

pH and EC levels have to be monitored.

Nutrient CANNA Hydro CANNA Aqua


Growing with hydroponics comes with many advantages, the biggest of which is a greatly increased rate of growth in your plants. With the proper setup, your plants will mature up to 25% faster and produce up to 30% more than the same plants grown in soil.

Your plants will grow bigger and faster because they will not have to work as hard to obtain nutrients. Even a small root system will provide the plant exactly what it needs, so the plant will focus more on growing upstairs instead of expanding the root system downstairs.

All of this is possible through careful control of your nutrient solution and pH levels. A hydroponic system will also use less water than soil based plants because the system is enclosed, which results in less evaporation. Believe it or not, hydroponics is better for the environment because it reduces waste and pollution from soil runoff.


Types of Hydroponic Systems

The cool thing about hydroponics is that there are many different types of hydroponics systems available. Some of the best hydroponic systems on the market combine different types of hydroponics into one hybrid hydroponic system. Hydroponics is unique in that there are multiple techniques you can use to get the nutrient solution to your plants.


Deepwater Culture

Deepwater Culture

Deepwater Culture (DWC), also known as the reservoir method, is by far the easiest method for growing plants with hydroponics. In a Deepwater Culture hydroponic system, the roots are suspended in a nutrient solution. An aquarium air pump oxygenates the nutrient solution, this keeps the roots of the plants from drowning. Remember to prevent light from penetrating your system, as this can cause algae to grow. This will wreak havoc on your system.

The primary benefit to using a Deepwater Culture system is that there are no drip or spray emitters to clog. This makes DWC an excellent choice for organic hydroponics, as hydroponics systems that use organic nutrients are more prone to clogs.

Nutrient Film Technique

Nutrient Film Technique

Nutrient Film Techinque, or NFT, is a type of hydroponic system where a continous flow of nutrient solution runs over the plants roots. This type of solution is on a slight tilt so that the nutrient solution will flow with the force of gravity.

This type of system works very well because the roots of a plant absorb more oxygen from the air than from the nutrient solution itself. Since only the tips of the roots come in contact with the nutrient solution, the plant is able to get more oxygen which fascilitates a faster rate of growth.


Aerogarden Aeroponics System

Aeroponics is a hydroponics method by which the roots are misted with a nutrient solution while suspended in the air. There are two primary methods to get the solution to the exposed roots. The first method involves a fine spray nozzle to mist the roots. The second method uses what’s called a pond fogger. If you decide to use a pond fogger then make sure you use a Teflon coated disc, as this will reduce the amount of maintenance required.

You may have heard of the AeroGarden, which is a commercialized aeroponics system. The AeroGarden is an excellent entry point to aeroponics. It’s a turn-key system that requires little setup. It also comes with great support and supplies to get you started.


Hydroponic Wick System

Wicking is one of the easiest and lowest costing methods of hydroponics. The concept behind wicking is that you have a material, such as cotton, that is surrounded by a growing medium with one end of the wick material placed in the nutrient solution. The solution is then wicked to the roots of the plant.

This system can be simplified by removing the wick material all together and just using a medium that has the ability to wick nutrients to the roots. This works by suspending the bottom of your medium directly in the solution. We recommend using a medium such as perlite or vermiculite. Avoid using mediums such as Rockwool, coconut coir, or peat moss because they may absorb too much of your nutrient solution which can suffocate the plant.

Ebb & Flow

Ebb and Flow System

An ebb & flow hydroponics system, also known as a flood and drain system, is a great system for growing plants with hydroponics. This type of system functions by flooding the growing area with the nutrient solution at specific intervals. The nutrient solution then slowly drains back into the reservoir. The pump is hooked to a timer, so the process repeats itself at specific intervals so that your plants get the desired amount of nutrients.

An ebb & flow hydroponics system is ideal for plants that are accustomed to periods of dryness. Certain plants flourish when they go through a slight dry period because it causes the root system to grow larger in search of moisture. As the root system grows larger the plant grows faster because it can absorb more nutrients.

Drip System

Drip System

A hydroponic drip system is rather simple. A drip system works by providing a slow feed of nutrient solution to the hydroponics medium. We recommend using a slow draining medium, such as Rockwool, coconut coir, or peat moss. You can also use a faster draining medium, although you will have to use a faster dripping emitter.

The downside to a system like this is that the drippers / emitter are famous for clogging. We prefer not to use drip systems, but it can be an effective method for growing if you can avoid the clogs that plague this type of system. The reason the system gets clogged is because particles from nutrients that build up in the emitter. Systems that use organic nutrients are more likely to have this kind of issue.


Why Choose Hydroponics?

Hydroponics is an excellent choice for all types of growers. It is a great choice because it gives you the ability to meticulously control the variables that effect how well your plants grow. A fine tuned hydroponic system can easily surpass a soil based system in plant quality and amount of produce yielded.

If you want to grow the biggest, juiciest, yummiest plants you can possible imagine, then hydroponics is the right choice for you. It may seem intimidating at first with all the equipment and work involved, but it will all seem simple enough once you get the hang of the basics. Start small, keep it simple, and your hydroponic system will never cease to amaze!



Advantages and disadvantages of hydro cultivation

The advantages of hydro cultivation include being able to accurately manage the nutrients, the amount of water given and the pH. But there are many more advantages. You will experience almost no problems with potting mix related diseases or weeds; the substrates used for hydro cultivation are weed and disease free, and this is why they are often referred to as sterile. Additionally measuring the pH and the electrical conductivity (EC) in the growing medium is simple. The electrical conductivity gives an estimate of the total amount of dissolved salts.

A disadvantage of hydro cultivation is that the substrate used is not always reusable or recyclable. Other disadvantages include the higher initial costs for the substrates themselves and the equipment required. But you can be sure to earn this back in the yields you achieve.

Table 1: Overview of advantages and disadvantages of run-to-waste with inert substrates:

Open system (run-to-waste) Closed systems (recirculating)
Advantages Plants receive continuously supply of fresh nutrients.

Also suitable for cultivation with ‘poor’ water quality (EC of 0.75 or higher)

No need to dispose via drainage.

Plenty of air available to the roots

Disadvantages More loss of water and nutrients.

Need to dispose of drainage water

Diseases can spread throughout the system via the feed water.

pH and EC values in the nutrients have to be monitored more closely




Inert substrates-The origins of growing on substrates

Even though the first farmers quickly discovered that plants grew better on the remains of other plants and dung, it was thousands of years before people understood exactly why. Research into plant food began many moons ago, long before our time, but only recently, about 150 years ago researchers found out exactly which substances in the dung actually feed the plants. And as a result of these discoveries, the artificial fertiliser industry was born.

Shortly before the dawn of this era, in the Netherlands Napoleon introduced monoculture, where one crop per field is cultivated. The combination of these new systems increased farming production to new levels. Initially the new developments produced tremendous results, but this success was quickly reversed. No one was familiar with these cultivation methods and they were certainly unaware of the drawbacks. The damage in the cultivation of vegetables was particularly noticeable. Year after year an excess of artificial fertilizers was applied creating problems in the potting mix structure and in the fertility of the ground. The same crops were grown year in year out in monoculture on the land. In turn the monocultures brought on a multitude of plagues. Potting mixes bound plagues were particularly difficult to counteract. A good solution was required urgently. Growers began placing the crops in separate compartments and cultivating them on growing medium instead of in the open ground, and this was the beginning of growing on substrates.

Growing on substrates was put into practice for the first time in the first half of the 20th century. As plastic containers became available growing on substrates made considerable progress. Production could be scaled up and automated. In practice it turned out that growing on substrates generated up to 25 percent greater yields compared to cultivating in the open ground. This is because the nu- trients can be adjusted directly to the circumstances at any particular time.

When CANNA HYDRO was introduced in the 1980s serious small scale cultivation became possible on inert media and rockwool in particular. This CANNA HYDRO formula has been used successfully worldwide for many years and even though many have attempted to copy the formula, no slabch has yet been developed.

Clay Pebbles


Clay Pebbles are made by forming clay into pellets and then firing these in a hot kiln. This causes the clay to expand and become porous. Clay Pebbles are available in various shapes and sizes and with two types of surface; smooth and coarse. Clay Pebbles have been used in horticulture since 1936. They have the advantage that, as long as they are well cleaned, they can be reused for up to five years. The greatest disadvantage of Clay Pebbles is that they can absorb almost no moisture, making them unsuitable as a run-to-waste substrate. However, they are widely used in recirculation systems where the nutrients continually pass by the roots. This is because Clay Pebbles have good supportive properties and are heavier than water and therefore do not float. In addition Clay Pebbles are used extensively as in potting mixes and as a drainage layer at the bottom of pots when growing in coir or in potting mixes.



Perlite is a glassy, volcanic rock that is ground and then baked at high temperature. Perlite is also inert, but due to its poor supportive properties it is relatively vulnerable as a growing medium itself. However, it can be used as a potting mix improver and particularly to increase the air ratio in the potting mix; though, these days there are environmentally friendlier methods for this, such as adding white peat.



Mapito is a very light medium with limited water retention capacity. This means that the substrate will dry out faster and so it needs to be watered more frequently. Mapito is a mixture of Polyurethane (PU), rockwool and sometimes coco or even perlite. Most types of Mapito are not “clean”, in that they often have a higher EC and a lower pH than the ideal growing medium; this is the great disadvantage of Mapito. So it is always essential to determine the exact pH and EC values of the Mapito and to rinse it thoroughly before use!


History of rockwool

How rockwool was discovered is not exactly known, one story goes as follows:
Rockwool was discovered by accident in 1840. After climbing a volcano in Hawaii researchers saw long, white threads hanging from the trees. The local inhabitants believed that these were God’s hairs which he pulled out of the volcano when he was displeased. However, investigation showed that the hairs of God were in fact Diabase, a liquid volcanic rock that was cooled and blown apart by the wind after leaving the volcano.

Nowadays rockwool is manufactured in factories. The volcanic rock is ground and pulverised to grit. This grit is then heated to 1500 °C, at this temperature it melts. This viscous substance is then poured onto a rapidly rotating sheet. This forms droplets and each droplet is stretched into a long fibre. These fibres are cured in a kiln and then con-solidated into slabs of rockwool. Any shape finished product can then be cut to size. In this process 1 m3 of raw slaberial becomes no less than 90 m3 rockwool. Besides the applications for thermal, fire and sound insulation, in the early 1970s it was discovered that rockwool could also be used as a good growing medium for plants. It was first used on a large scale for cultivation in the Netherlands in 1975.
The rockwool used in construction for thermal and sound insulation is not suitable for cultivating plants. This is because mineral oil is added to make the slaberial water-repellent.

A rockwool variant has been specially developed for horticulture which can actually absorb and retain large quantities of water. This rockwool has considerable capillary capacity, in other words, rockwool can retain large volumes of water. This type of rockwool can retain up to 80% water and still contain 15% air. The remaining 5% is the rockwool itself.

Because each crop has different requirements, different types of rockwool have been developed. The main differences are in the structure of the fibres, horizontal or vertical, their thickness and density. Rockwool is available in various shapes and sizes; for example small plugs or cubes, for germination and propagation, in which seeds or cuttings can take root. These cubes fit into blocks where the young plants can continue to grow. There are also slabs in all imaginable dimensions. These are also known as slabs on which you can place the blocks with young plants.

Many plants don’t like having “wet feet”. A rockwool slab that is too soft will retain too much water, and one that is too hard will provide too much resistance to the growing roots. A hard slab means that the plant spends a great deal of its energy developing roots – energy that the plant can better use for growing above ground. Therefore the ideal rockwool slab is not too hard and has a horizontal structure so that there is ample volume available for root growth. The quality of a plant is largely determined under the ground, in fact 50%, so the bigger the root volume, the healthier the plant and the higher the yield.

Most rockwool slabs are wrapped in plastic, which makes them easy to pre-soak. The patches that remain dry during the pre-soak will not get any wetter during cultivation; so it is important to work carefully in the pre-soaking phase.


Impact on the environment

One aspect of growing that is often forgotten is the waste feed water that drains into the sewerage system. The drainage water from CANNA HYDRO nutrients does not contain any serious pollutants, so the burden on the environment is minimal. Another significant difference between CANNA HYDRO nutrients and other products for run-to-waste cultivation is the raw slaberials used. Because CANNA carefully selects the purest possible raw slaberials for its products there are considerably fewer heavy metal particles in the drainage water. Another important difference with other run-to-waste products is that the CANNA HYDRO nutrients recipe does not contain any red iron. The notion that red iron is more easily absorbed by plants is only valid at higher pH values; the pH range maintained in run-to-waste cultivation systems is too low. Large quantities of red iron are added to many products to ensure that there is sufficient iron for the plant to absorb, but much of this iron is not taken up by the plant. So instead of red iron, CANNA uses a special yellow variant in its HYDRO products. This yellow iron variant is absorbed well by the plant at the pH in the root environment. So considerably less yellow iron is needed than of the widely-used red iron. The idea that run-to-waste systems are more harmful to the environment than recirculation systems is therefore not entirely correct. There is waste water in both systems; a constant trickle in run-to-waste systems and in recirculation systems a relatively large amount from time to time. The amount of waste water depends on the watering system and the dryness of the substrate, a dry substrate requires more feed water than a wet substrate, and thus not on the type of cultivation system.


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