There are a wide number of essential minerals that are known to be important for the plants development. The most crucial ones are called “Macronutients”. We generally put the following in this category: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sulfur (S), magnesium (Mg), carbon (C), oxygen(O), hydrogen (H). Others called “Micronutrients” or “Trace minerals” are needed in lower quantity. They are: iron (Fe), boron (B), chlorine (Cl), manganese (Mn), zinc (Zn), copper (Cu), molybdenum (Mo), nickel (Ni).

In a classic garden the worms are constantly mixing the deep soil with the surface and raise minerals to the surface. This action brings the macro and micronutrients available for the fungus, bacteria and plant roots.

In aquaponics we don’t have this link between deep soil/rocks and the ecosystem. We are only relying on the fish food added to the system.

The fish food profile is different between brands but is generally high in nitrogen, Phosphorous, Potassium but rarely covers all needs of the plants. Unfortunately the worms and fungus are not able to have access to rocks and make them available to the plants. A good way to fix this situation is to add rock powders into the system.

This can be under the form of rock dust or more elaborated mineral element powders. It will allow the life of the system to have access to all the minerals needed for the plants.

The quantity to add is difficult to evaluate. I generally recommend 2mg/1000L or growbed square meter. The frequency is also tricky to evaluate. Some aquaponics growers like to add the powder once a month.

I personally prefer to add it when I can see the first signs of deficiency on my plants. In winter I ca run the system for months without adding any minerals but in summer I generally add some every other month.

There is one mineral that is very quickly oxidised in aquaponics due to the moist and aerobic (in contact with oxygen) environment and this is the iron. Iron turns into rust none available for the plants. The best way to regulate this problem is to add chelated iron which is a special iron that is encapsulated in another particle.

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If you don’t have the chance to see the full video, here is the transcription:

Why, how and when should we add minerals in aquaponics? This is what we’re going to see together in this video. Welcome in this video. We’re going to talk about minerals in aquaponics.


My name is Jonathan and I give you some free video to help you to build your own aquaponics system and to manage it in the best way possible. I offer you a free training from the description of this video. You’re going to find a link, also in the “I” like information in the corner of the video. It’s a free training to really give you a lot of information, a lot of knowledge to be able to basically produce some food in your own backyard, thanks to aquaponics that is sustainable, healthy, and tasty.


So today, we’re going to see why we put minerals in our aquaponics system. So first, I would like to compare the aquaponics system to a classic garden. In a classic garden, you got lots of things happening. Obviously, there is what you see. You got plants that are growing from the soil, but the soil is actually composed of a lot of organic matters that are in decomposition. They are breaking down, thanks to some bacteria, fungus, insects, worms, a lot of life. It’s a real ecosystem that you have in your oil, a normal soil. I’m not talking about the industry or agriculture that is relying on fertilizers, and that I am completely against.


So I’m talking about normal practice, permaculture or what is happening in a classic forest. So now in a normal forest, or in a good garden, you got a lot of activity but you got some worms, and those worms they are going around and they are breaking down all those organic matters and they release all the nutrients for the plant.


So the plants to grow, they need a range of nutrients. First, they need nitrogen. So nitrogen is – we base the aquaponics principle on the nitrogen cycle. You know, you basically have some fish food. This fish food is transformed, thanks to some bacteria into nitrate and the nitrate is absorbed by the plants. That’s basically fertilizer, the nutrients of the plants, natural, completely natural. And that’s what is happening in a garden as well. Any type of an old leave that is just dead on the floor is going to be transformed, thanks to some insects and then worms and then some bacteria and fungus are going to break it down and release it available for the new plants that are growing.


So that’s we call the cycle of life because every time you got something that is dying, it’s going to be a source of food for the plants that are growing, the new plants. So it’s fantastic and that’s we rely on in aquaponics.


But the plants they don’t only need nitrogen. They need also phosphorous and potassium (NPK) that are the three main nutrients that we all talk about in aquaponics. They are available in the soil, but you also got all the essential minerals that are very important for the plants.


There are 12 that are well-known and then there is a bunch of others are around and the plant needs a very wide range of minerals, essential minerals to live and to develop the best aroma, the best crop, basically.


So in your soil, those minerals they’re available simply because the worms are going up and down in the soil. You know, they make some tunnels and they go very deep in the soil and there, there are some rocks, big rocks and small rocks and smaller and smaller and basically, they mix the soil. So they always bring rocks near by the plants. And that’s where basically the bacteria and the fungus can transport those nutrients and those minerals.


So you got a real network in the soil that is just magic but that’s what is happening and that’s why we are talking about ecosystem. That’s why having a good ecosystem is so important because when you got a good ecosystem, basically, you have all the nutrients that are available to all those links of the ecosystem.


In aquaponics, it’s different because we are working without access to the soil. We are working on a media where you got an ecosystem as well, but there are no rocks that are breaking down and that are going to release some minerals available for the plants.


So at one point or another, if you grow food in aquaponics without adding minerals, you will probably find some deficiencies in the plants that you are growing. If you follow my recommendation, you have a large biodiversity and every single plant has got different needs, which is good because, on the average, it means that they’re going to use all the nutrients that are available.


But you need to make sure that you’re going to offer those minerals, and if there is one deficiency in one mineral, you’re going to find one typical species of plant that is going to start to have some yellow leaves, and then if you look at it closely, you’re going to find that it can be a deficiency in some minerals.


So in this case, what I do I add some minerals into my water. So then the frequency, the quantity is very hard to determine because it depends on the crop you’re going to grow. And also, it’s very difficult to balance the quantity of minerals.


You know, if you work in hydroponics, the solution that you’re going to put in your water is going to perfectly adapted to the type of plants that you want to grow. So one solution per type of plant.


In aquaponics, it’s different, right? We are in a mixed growth with mixed culture where you’ve got different types of plants so what we want to have is that we want to make sure we got enough minerals in our aquaponics system to fulfil the needs of all the plants. But we don’t want to adapt it specifically to one crop.


So we know that there some very, very complex reactions between the plants, the bacteria, and the fungus. Some people think that the plants are asking the fungus and the bacteria to work for them and to find the minerals that they need.


So the reality is that you just need to have some minerals somewhere in the aquaponics system in the water and this relationship between bacteria, plants, and fungus is going to bring them available to the plant.


Now, how to bring those minerals in the aquaponics system there are different ways. What I do is that I add rock dust in the aquaponics system. So rock dust is simply some rocks that have been grinded into powder and when you add this powder into this aquaponics system, it releases all the different minerals in the water and available for the bacteria, fungus, plants, insects or whatever.


So that’s a really good way to do it. Now, the quantity required is very difficult to determine. You never know if you are putting too much or not enough. What I do is that I read, I look at the leaves of my plants. As soon as I see a plant with deficiency, I’m going to add some minerals in the aquaponics system and generally speaking, I add 2 milligrams per thousand liter of water.


And then the frequency is that I’m not going to add more and then some people add it every month, every two months. What I do is I just have a look at the leaves and if I see a deficiency in the leaves, I’m going to add it again a bit later.


If I see that all the leaves are nice, green, strong green, I’m not going to add any more, and sometimes I can go for months without adding any minerals in the aquaponics system.


Now, there is a specificity on the iron, and I’m not going to develop this topic here because I already made some video about this, and I will probably make others in the future, but I don’t want to spend too much time in this specific video talking about iron. But you know that when you put iron in contact with water and oxygen, and specially with specific pH, you’re going to have the iron that is going to be oxidized and transformed into rust.


This is what happens in aquaponics when you put iron in the water and therefore, it’s not available for the plants anymore. So we use chelated iron. This is an iron that is encapsulated into another molecule, and this other molecule is basically protecting the iron. So it avoids it to turn into rust.


So if you want to know more about it, again, I offer you a free video in the description of the video just below. You’re going to find a link. You click on the link and then you will have access to a free training, a six-step training to build your own aquaponics system and to manage it in the best conditions. So I will give you a lot of free information to really succeed at producing some sustainable, healthy, and tasty food at home, in your own backyard.


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