How To Choose The Right Growing Media
Hi, I’m Shiran from Aqua Gardening,
One of the most common questions among people that want to start an Aquaponics system, is which growing media to use.
The growing media has 2 main purposes, the first one is to hold the plant, and the second is to act as a filter for the system by providing surface area for beneficial bacteria to grow on.
The bacteria are the ones that drive the system, without them the fish waste will not convert into plant food. So you need to make sure you have enough bacteria to make the system work!
Let’s look at the differences between the grow media that suits aquaponics, including Clay balls, scoria, gravel, and pumice.
Clay balls made from baked clay, and are very porous and light weight.
The Biggest benefit they have is that they have the most surface area for bacteria to grow on compared with other growing media, that means that you will get more filtration from your grow bed, and may not need an additional filter to supplement your system.
Another big benefit is that the clay is completely sterile and pH balanced!
This is important when considering natural media, because trace elements inside it can change your water chemistry.
And the best reason for clay balls and that it is very gentle on the hands compared with other growing media, so even the little ones can play with it and dig a hole, without cutting themselves, and it will not damage your new nail polish either.
Keep in mind that some clay ball manufacturers produce very light porous product, and it will float in your grow bed and prevent plants from getting a grip to grow. At Aqua Gardening we will never stock clay balls that float, this’s our promise to you.
The second popular growing media for aquaponics is gravel.
However using gravel can cause problems in your aquaponics system because it isn’t sterile and can contains trace elements. This can negatively affect your water chemistry that harm and even kill you rfish!
But the biggest issue with gravel, is the fact it is not porous, and there is minimal surface area for bacteria.
This means as your fish grow your filtration may not keep up and you will need to buy or make an external filter. That is why we don’t recommend it. It’s also heavy and rough on the hands when doing maintenance or planting.
The next media is Scoria, which has a lot of arguments and discussion around its suitability for aquaponic use. So what are the facts?
Scoria is a volcanic rock that forms from basaltic magma. It’s very porous, which makes it great for Aquaponic use, and it is cheaper than clay balls. But Scoria contains 50% silica and 10% calcium, and many other trace elements. The calcium is good for Aquaponics, as long as you can control it, but the problem is you can’t with scoria! Therefore you will have pH issues when using Scoria, and they will be impossible to fix!
This is why we never recommend using Scoria as it makes your system impossible to control and can kill your fish. Scoria is also rough on the hands.
Pumice is a volcanic rock as well, but does not contain many minerals. It is very heavy, but porous, which makes it somewhat suitable for aquaponics.
However it is expensive to buy, and hard to move around in large quantities due to it’s weight.
That is why we recommend using caly balls because they are far cheaper and more effective.
If you do decide to use any other grow media except from clay, do the following small spot test to make sure it does not contain calcium. Simply take white vinegar and pour it over the medium.
If it bubbles, its trouble, do not use it!
We still recommend that its not worth the risk trying to save a little money on your growing media when it can have such disastrous impacts on your fish and plants. And remember, you only need to buy your growing media once and never have to replace it again – so do it properly the first time.
Keep watching to learn more about aquaponics, or click on the link below to find out how you can access our members only online video training, something not offered anywhere else in Australia! I’m Shiran from Aqua Gardening, and thanks for watching.