This article will show which plants can be cultivated in an aquaponic system. Before going into detail about the individual plants, however, it is important to understand which systems exist in the world of aquaponicsc, as some plants work better in system A than in system B, for example. Still others, on the other hand, have proven themselves in system B. This alone makes it clear that there is no such thing as the best system or the one system, and that when setting up or planning the design, you should pay close attention to which plants the system should be suitable for.

First of all, however, it can be said: theoretically, any plant can be cultivated in an aquaponic system. However, there are some exceptions where conventional methods work better. More on this later in the individual categories.  In this article you will find a list of experiences with individual plants.

Salads and herbs
Salads and herbs are probably the group of plants that work best in aquaponics. They are usually weak growers and are well taken care of in the aquaponic system. I have personally experienced lettuces that have grown strong, thick and robust with the help of aquaponics, so that biting into a single leaf felt like biting into a juicy piece of meat. Really crunchy.

What's more, lettuces and herbs will grow in any system, whether standing in gravel (Steady Flow / Flood & Drain), in planters both on polystyrene or similar (DWC) or in PVC pipe (NFT).

Recommended varieties:

Any lettuces such as chard, spinach, lettuce, iceberg lettuce, endive, rocket, purslane and so on have proved successful as have herbs such as basil, parsley, thyme and oregano.

Not recommended:

Mint should be avoided in the aquaponic system because it is rampant. It loves humid locations and is like paradise in an aquaponic system. Should it have its own system in isolation, there should be no problems, but together with other plants it will have overgrown them in no time.

Fruit vegetables
Fruiting vegetables belong to the group of highly nutritious plants and are also very popular in the aquaponic system. However, it should be borne in mind that some fruit vegetables can grow very large. Sufficient space above and below should be provided accordingly.

Tomato plants, for example, grow enormously. I have heard of cases where the tomato plant has grown over eight (8!) metres tall. For most people, this should represent a height that either does not fit into the desired space or makes any care of the plant an impossible task. Alternatively, cocktail tomatoes or vine tomatoes can be planted, which usually remain much smaller.

Cucumbers and other squash plants grow very wide and quickly overgrow the entire space. Here, too, thought should be given in advance to whether this space is available.

Furthermore, not every system is suitable for fruiting vegetables. Neither a DWC nor an NFT system is normally capable of supporting such large plants. Theoretically, this is also possible, but it would have to be readjusted regularly with supporting measures, for example with ropes or other suspensions.

Recommended varieties:

I would recommend smaller fruiting vegetables, such as chilli plants or peppers, for private households. Smaller tomato plants, such as cocktail tomatoes, are also possible.

Not recommended:

Any cucurbits, tomatoes and other plants that grow very large should only be cultivated with caution in an aquaponic system. Due to the high nutrient content in the water, enormous results can theoretically be achieved, but practically only if there is enough space.

Root and tuberous plants
Botanically not quite correct, but certainly acceptable for understanding: I count plants that develop edible parts underground as root and tuber plants, such as potatoes, carrots, beetroot, ginger, turmeric, parsnips and the like.

Theoretically, it is also possible to cultivate these plants in an aquaponic system, but some prerequisites are necessary here.

Soft tubers, like potatoes, should not be planted in the gravel bed (Steady Flow / Flood & Drain), as the tuber would form around the gravel. This could cause enormous toothache when eaten. Instead, for soft tubers, the Aeroponics method has proved successful.

With harder tubers, such as ginger and turmeric, the gravel bed is again possible, as their strength gradually pushes the gravel away.

Recommended varieties:

Ginger and turmeric I can recommend at this point, but only if there is enough space.

Not recommended:

Potatoes, carrots and other plants with relatively soft tubers I can only recommend if the necessary conditions have been created - see Aeroponic.

Leek plants
Leeks include the edible onion, the winter onion, the spring onion, chives, garlic, leeks and many more. All of these grow excellently in the aquaponic system.

Recommended varieties:

Depending on personal taste, pick one or two from the list of leeks that can grow alongside. They are easy to care for and the upper parts of the plants can be harvested several times during the year.

Not recommended:

Although onions and other leeks go well with almost any dish, care should be taken not to grow too many.

Exotics
As described above, theoretically any plant can be cultivated in an aquaponic system, as long as the necessary conditions are met. There are cases where even the cultivation of a banana and papaya plant has been successful in a specially constructed aquaponic system.

Summary:
Theoretically, any plant can be cultivated
Salads, herbs and allium plants grow particularly well and are easy to care for.
In the case of fruiting vegetables, it should be considered in advance whether there is enough space and room for them to develop.
Root and tuberous plants are only recommended under certain conditions.
Give free rein to creativity and inventiveness

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Aquaculture is not aquaponics

Actually, today we consume much more fish than there is in the oceans and lakes.

Aquacultures in the seas and lakes are the basis for the high fish consumption. Today, aquacultures seem to be the solution at all to cover the high demand for fish, but there are also negative consequences for humans and the environment, especially for organisms living in the water. It is clear that more than half of all fish products consumed worldwide already come from aquaculture.

But what exactly is aquaculture? Aquaculture or aquafarming is the systematic breeding and catching of fish, seafood, etc. in freshwater or seawater. However, there is a big difference compared to traditional fishing. In traditional fishing, fish are taken from public waters, whereas in aquafarming the individual fish species are kept in separate net pens where they are bred, fed and then caught.

This is done in the sea, in pens or in water tanks. The fish are therefore the property of the keeper and can only stay in their net enclosure, unlike fish that are fished in the traditional way. There are many additional problems in free-range farming: the unconsumed feed simply falls to the bottom in the sea and above a certain quantity this leads to undesirable reactions from the environment.

The differences between the systems
It is already clear that in aquaculture and hydroponics, environmental aspects and a higher production volume play a decisive role. The systems pollute the oceans and farmland less with by-products and can also be operated without being tied to a specific location. The difference is this: Hydroponics is for growing plants, aquaculture for breeding animals.

In aquaponics, the two systems are combined to make the disadvantages of each work to the advantage of the other. Hardly any water is lost because the loops are almost closed - with the exception of the extracted material (obs, vegetables, fish, etc.), extremely little water leaves the system. This means that only a correspondingly small amount of water is actually used. In addition, fertiliser or nutrient solution does not have to be added to the system on a regular basis. Aquaponics can therefore also be described as a further development of aquaculture and hydroponics.

Aquaponics - Combined systems
Setting up an aquaculture system or a hydroponic system is not very complicated, and there are two possible approaches: to set them up separately or to build a combined system. In aquaponics systems, the advantages of the two systems described are simply combined. Plants are only grown in a substrate, the fish are kept in a large tank.

A substitute for soil is expanded clay, even if it is not cheap. Gravel, rock wool, coconut fibre or other materials are also possible, but require some testing, as not all plants tolerate all variants equally.

An essential part of the cycle is the collection tank for the hydroponic water in which the fish are ultimately kept. These are supplied with nutrients and oxygen by the plants. The excretions of the fish provide the plants with almost everything they need. The result is that, apart from a little water, no additives need to be used. The closed system works autonomously, except for a small water pump.

So much for the theory, here is an interesting study by the South Westphalia University of Applied Sciences that shows the entire problem of such a system in real life.

Aquaponics is a process that combines the rearing of fish in aquaculture with the cultivation of plants in hydroponics. There are various approaches to transferring the nutrients produced by the fish to the plants.

Here you will find an overview of the different types of planting.

An overview of aquaponics system types can be seen here.

Both aquaponics and hydroponics systems are always part of a closed-loop system. Aquaponics, for fish production, always includes a hydroponic system for plant cultivation. The system works by using the waste from fish farming as nutrients for the plants. This happens automatically in our systems via dosing systems. By appropriately controlling the nutrient supply – which is optimized for the selected plant species and development stage – the closed loop ensures that well over 90% of the necessary nutrients, i.e., the investment, are actually contained in the two final products (vegetables and fish).

In contrast to soil-based planting, the following advantages arise

- High yield: 500m ² produces up to 8 tons of fish and 16 tons of tomatoes per year.

- Minimal space requirement: Profitability from 500 m ²

- Weather independence: Year-round operation and yield

- Independence from precipitation: closed cycle

- Very low water consumption

- No use of pesticides

- No use of herbicides

- No use of medication

- No damage to groundwater: closed circuit

We offer control systems for the automated management of your aquaponics and hydroponics systems. Our offerings range from systems used solely for documentation purposes to fully autonomous system control.

Related article: What is aquaponics?

Aquaponics and hydroponics: situation, market demand and development

Food production depends on the availability of resources such as land, freshwater, fossil energy, and nutrients (Conijn et al. 2018), and the current consumption or depletion of these resources exceeds their global regeneration rate (Van Vuuren et al. 2010). The concept of planetary boundaries aims to define the ecological limits within which humanity can operate with respect to finite and sometimes scarce resources (Rockström et al. 2009).

Biochemical flow limits that restrict food supply are more stringent than climate change (Steffen et al. 2015, see figure below). In addition to nutrient recycling, dietary changes and waste prevention are essential to transforming current production (Conijn et al. 2018; Kahiluoto et al. 2014). Therefore , a major challenge is to shift the growth-oriented economic model to a balanced ecological economic paradigm—replacing infinite growth with sustainable development (Manelli 2016).

To achieve a more balanced, practical and sustainable situation, innovative and ecological farming systems are required so that trade-offs between immediate human needs can be balanced while preserving the biosphere's ability to provide the necessary goods and services (Ehrlich and Harte 2015).

In this context, aquaponics (aquaculture + hydroponics) has been identified as an agricultural approach that can contribute to achieving both planetary boundaries (see figure below) and sustainable development goals through nutrient and waste recycling, especially in arid regions or areas with non-agricultural soils (Goddek and Körner 2019; Appelbaum and Kotzen 2016; Kotzen and Appelbaum 2010).

Aquaponics is also seen as a solution for utilizing marginal land in urban areas for near-market food production. Once a "backyard technology" (Bernstein 2011), aquaponics is now rapidly evolving into industrial production, as technical improvements in design and practice have significantly increased production capacity and efficiency. One such area of ​​development is coupled and decoupled aquaponics.

Traditional designs for single-loop aquaponics systems include both aquaculture and hydroponic units, with water circulating between them. In such traditional systems, compromises are necessary regarding the conditions of the two subsystems in terms of pH, temperature, and nutrient concentration (Goddek et al. 2015; Kloas et al. 2015, Chapter 7).

A decoupled aquaponics system can reduce the need for compromises by separating the components and allowing the conditions in each sub-system to be optimized.

Especially the problem of complex transport

(From the region for the region) is increasingly becoming an environmental and cost problem in cities.

Initial experiments, such as the cultivation of herbs in hydroponic systems, which can be seen in the first supermarkets and retail stores, illustrate the potential with the effect of reducing costs by saving on transport and storage, as well as gaining customer acceptance and their interest in the problem of future supply, since the herbs can be picked on site by the customer themselves in these systems.

The picture shows a system in a supermarket of the Edeka chain of the company Infarm / Berlin.

According to the World Wildlife Fund for Nature (WWF), approximately 70 percent of global freshwater consumption is used for agriculture and processing. In contrast, aquaponics enables food production with 50 to 90 percent less water consumption: the savings are 50 percent compared to traditional single-circuit systems – simply due to the dual use of water.

A dual-circuit system with water recovery even achieves savings of around 90 percent. In this production system, fresh water only needs to compensate for losses due to evaporation and the removal of biomass from the system.

Available resources for nutrition

Given the resource situation, a rethinking of food supply is inevitable. The current status of the control variables for seven of the planetary boundaries described by Steffen et al. (2015) is shown in the graph above.

The green zone is the safe operating range, the yellow zone represents the zone of uncertainty (increasing risk), the red zone is a high-risk zone, and the gray zone boundaries are those that have not yet been quantified. The blue-bordered variables (i.e., land system change, freshwater use, and biochemical fluxes) indicate the planetary boundaries on which aquaponics can have a positive impact.

This graph clearly shows that the "limits to growth" (Club of Rome, 1972) have already been reached. Traditional agriculture is already experiencing significant yield losses, not least due to soil depletion by various chemicals (such as glyphosate, see BUND study, 2013) – at least where the use of this chemical is still permitted.

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ID: 7

The choice of hydroponic system

The choice of the type of irrigation depends on a wide variety of factors such as the cost of setting up the system, operating costs, space requirements, water consumption, desired productivity (yield) and many other aspects. To help you make a decision, we have created an example for you here that can give you a first impression of the trade-offs to be expected.

The system used in this example is called DAR (Decision Analysis and Resolution) and comes from industry. It is a tool to precisely and accurately formulate different variants and alternatives in the realisation of a complex project, to weight the individual aspects and from this to make a decision for or against a certain variant of a project. Furthermore, it also makes it easier to summarise subjective arguments in figures and values that facilitate decision-making. In retrospect, the decision-making process can be easily understood.

Here is just a simple overview of individual factors. Please contact us for a detailed consultation that is tailored exactly to your needs. Among others:

• Type of system
• Space requirement
• Energy requirements
• Reliability
• Productivity
• Construction costs
• Operating costs
• Break Even Point
  etc.

An initial decision-making aid

• Energy costs
• Thermal insulation overview
• Plant types
• Decoupled aquaponics
• Operating modes
• Biofilter

  DAR (Decision Analysis and Resolution) as Excel 97–2003 (.xls)

  DAR (Decision Analysis and Resolution) as Open Document (.ods)

Our offer: Our Services

Fertiliser programmes

Mixing hydroponic fertiliser yourself ?

The commercially available fertilisers consist of a complete fertiliser supplemented with macronutrients. They are offered by some hydroponics and/or fertiliser companies and vary depending on the hydroponic plant. An example of a fertiliser programme is the hydroponic tomato programme offered by Hydro-Gardens.

In this programme, growers purchase Hydro-Gardens Chem-Gro tomato formula. It has a composition of 4-18-38 and also contains magnesium and micronutrients. To make a nutrient solution, it is supplemented with calcium nitrate and magnesium sulphate, depending on the variety and/or growth stage of the plant.

Advantages of fertiliser programmes

Disadvantages of fertiliser programmes

Modified Sonneveld recipe / herbs

It is at the discretion of the breeder which fertilizers he uses to produce a nutrient solution according to a recipe. The fertilizers commonly used include:

Advantages of nutrient solution recipes

Nutritional solutions allow fertilizers to be adjusted based on the nutrients contained in water sources. An example: A gardener uses a water source with 30 ppm potassium and produces the modified Sonneveld solution for herbs that requires 210 ppm potassium. It would have to add 180 ppm potassium ( 210 ppm - 30 ppm = 180 ppm ) to the water in order to obtain the amount of potassium required in this recipe.
With recipes, nutrients can be easily adjusted. When a leaf analysis report indicates that a plant has iron deficiency. It is easy to add more iron to the nutrient solution.
Since recipes make it easy to adapt, fertilizers can be used more efficiently than in fertilizer programs. Using recipes can be less expensive than using fertilizer programs.

Disadvantages of nutrient solution recipes

It has to be calculated how much fertilizer has to be added to the nutrient solution. (Link to performing calculations). Some people may feel intimidated by the calculations involved. However, the calculations only require uncomplicated mathematical skills based on multiplication and division.
A high-precision scale is also required for the measurement of micronutrients, since the required quantities are very small. Such a scale can be found on Amazon from 30.- €: e.g .: KUBEI 100g / 0.001g.

This is about the calculation of nutrient solutions for your own needs

Picture: Boston Public Library is licensed under CC BY 2.0

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ID: 415

Calculation of the concentrations of nutrient solutions using the following two equations

The calculation of the amount of fertilizer that has to be added to the nutrient solutions is part of a successful hydroponic production. Only multiplication, division and subtraction are used for the calculations; no advanced mathematical knowledge is required.

If you want to know more about the compositions and concentration information, the article series can be too Stoichiometry and a look at the conversion of Mol and grams When specifying the concentration of the individual elements and connections, it is helpful to better understand the complexity of the topic.

If you master the general process, producing nutrient solutions and adjusting the amount of nutrients is child's play.

Fertilizer recipes for hydroponics are almost always given in ppm (in the long form: parts per million). This may differ from the fertilizer recommendations for growing vegetables and fruits outdoors, which are generally given in lb / acre (pounds per acre).

First you have to convert ppm to mg / l (milligrams per liter) using this conversion factor: 1 ppm = 1 mg / l (1 part per million corresponds to 1 milligram per liter). For example, if 150 ppm nitrogen is required in a recipe, 150 mg / l or 150 milligrams of nitrogen in 1 liter of irrigation water are actually required.

Ppm P (phosphorus) and ppm K (potassium) are also used in recipes for nutrient solutions. This also differs from the fertilizer recommendations for growing vegetables and fruits in the field, which use P2O5 (phosphate) and K2O (potash). The fertilizers are also given as phosphate and potash. Phosphate and potash contain oxygen, which must be taken into account in hydroponic calculations. P2O5 contains 43% P and K2O contains 83% K.

Let us check the previous circumstances:

1 ppm = 1 mg / l
P2O5 = 43% P
K2O = 83% K

Nutrient solution tanks are usually measured in gal ( gallons ) in the United States. When we convert ppm to mg / l, we work with liters. To convert liters into gallons, use the conversion factor of 3.78 l = 1 gal ( 3.78 liters corresponds to 1 gallon ). The invoice is also given below for continental interested parties.

Depending on the scale you use to weigh fertilizers, it may be useful to convert milligrams into grams: 1,000 mg = 1 g ( 1,000 milligrams correspond to 1 gram ). If your scale measures in pounds, you should use this conversion: 1 lb = 454 g ( 1 pound = 454 grams ).

Let us summarize these circumstances:

3.78 l = 1 gallon
1000 mg = 1 g
454 g = 1 lb

Now we have all the necessary circumstances. Let's look at an example.

How do you determine how much 20-10-20 fertilizer is needed to deliver 150 ppm N with a 5 gallon tank and a fertilizer injector that is at a concentration of 100:1 is set?

First, write down the concentration you know you want to reach. In this case it is 150 ppm N or 150 mg N / l.

Note that we multiply by 1. This allows you to cancel the units that are the same in the numerator and denominator. Now we can paint "mg N" and get the unit g N / l water.

Continue this process by converting liters into gallons. Most containers are still traded in gallons ( 3.78 liters ). Entertaining here: the metric system was invented by the Britten. If you want a metric result, omit this calculation step.

Now there are only grams of nitrogen left per gallon of water.
We'll get closer to it. Now we want to convert grams of nitrogen into grams of fertilizer. Remember that our fertilizer is a 20-10-20, which means that it contains 20% nitrogen. It can be imagined that 100 grams of fertilizer contain 20 grams of nitrogen. 

So where do we stand now? We calculated how many grams of fertilizer are needed in each gallon of irrigation water. At the moment we have a normally strong solution. Our example prompts us to calculate a concentrated solution of 100: 1. This means that for every 100 gallons of water that are applied, 1 gallon of stock solution is also applied via a fertilizer injector. We also know that our storage tank holds 5 gallons. Below see calculation for metric system (liters).

In gallons

In the calculator: 150 x 1: 1000 x 3.78 x 100: 20 x 100 x 5 is 1417.5 grams on 5 gallons of water (in the storage tank)

After we have deducted everything, we have a gram of fertilizer left. This is the amount of fertilizer we need to put in our storage tank to apply 150 ppm N at a concentration of 100: 1. Multiply and divide and you get the answer 1417.5 grams of fertilizer.

In liters

In the calculator: 150 x 1: 1000 x 100: 20 x 100 x 10 is 1500 grams per 10 liters of water ( in the storage tank )

After we have deducted everything, we have a gram of fertilizer left. This is the amount of fertilizer we need to put in our storage tank to apply 150 ppm N at a concentration of 100: 1. Multiply and divide and you get the answer 750.0 grams of fertilizer.

This means that for every 100 liters of water that is applied, 1 liter of stock solution is also applied via a fertilizer injector. We also know that our storage tank holds 10 liters. 

If we measure in pounds, we have to put 0.75 kg / 1.15 lb fertilizer in our storage tank to apply 150 ppm N with a concentration of 100: 1.

You have just completed one of the two equations. Now let's look at the other one.

We just found that we need to add 750 grams of fertilizer to deliver 150 ppm nitrogen at a concentration of 100: 1. The fertilizer we used was a 20:10:20. In addition to nitrogen, we also add phosphorus and potassium. With the next equation we determine how much phosphorus we supply. This is basically the reversal of the first calculation.

We start with the amount of fertilizer that we put in our tank. The final units are ppm or mg / l. As with the previous calculation, we use our specifications until we receive these units.

Multiply with the concentration of the nutrient solution.

Multiply to convert to liters.

Next, convert milligrams of fertilizer into milligrams of phosphate.

Next we will convert grams of phosphate into grams of phosphorus, assuming that phosphate contains 43% phosphorus.

Finally, we convert grams of phosphorus into milligrams of phosphorus.

When we calculate this, we find that we have added 32.25 mg / l P or 32.25 ppm P. This is the second equation. We can also use them to determine how much potassium we have added. 

We added 124.5 mg / l K or 124.5 ppm K.

With these two basic calculations, you can use any nutrient solution recipe program. How they are used to calculate a recipe can be seen in this article:

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ID: 416

Now that you have the two basic equations for the production of nutrient solutions, we want to use them to calculate the amounts of fertilizer required for a nutrient solution recipe.

If you are not familiar with the two equations, read this first: Hydroponic systems: Calculating the concentrations of nutrient solutions using the two equations.

Here is our problem: We want to use a modified Sonneveld solution (Matson and Peters, Insidegrower) for herbs in an NFT system. We use two 5-gallon containers and injectors set to a concentration of 100: 1 and call them storage tank A and storage tank B. How much of each fertilizer do we have to put in each storage tank ?

You may be asking: why two storage tanks? This is due to the fact that certain chemicals in our fertilizer solution react with each other as soon as they come into contact with each other. In all nutrient solutions ( fertilizer mixtures ) you have calcium, phosphates and sulfates - among other things, these three chemicals for all plants vital are. The last two react with calcium and are no longer present in the form we need in our nutrient solution. They connect to each other and fall to the bottom of the container as white flakes ( precipitates ). Therefore, phosphates and sulfates must be kept separate from calcium and, when introduced into the nutrient solution of the ( system, saved from direct mixing by means of a dosing pump or measuring cup ).

Modified Sonneveld recipe for herbs

These are the fertilizers that we will use. Some fertilizers contain more than one nutrient in the recipe, while others contain only one. Here is a small overview Commercial fertilizer from which you can put together your recipe

The first thing you notice is that we have three sources of nitrogen (calcium nitrate, ammonium nitrate and potassium nitrate), have two sources of potassium (potassium nitrate and potassium phosphate monobasic) and one source of calcium (calcium nitrate) and phosphorus (single-base potassium phosphate). We can start calculating the calcium or phosphorus in the recipe because only one fertilizer provides each nutrient. Let's start with calcium.

The recipe provides 90 ppm calcium. We calculate how much calcium nitrate we need to use to achieve this by using the first of our two equations.

We need to add 895.3 g calcium nitrate to get 90 ppm calcium. However, calcium nitrate also contains nitrogen. We use the second equation to determine how much nitrogen should be added in ppm.

We add 73.4 mg N / l or 73.4 ppm nitrogen. Our recipe provides 150 ppm nitrogen. If we subtract 73.4 ppm nitrogen from it, we have to add 76.6 ppm nitrogen.

Let us now calculate how much single-base potassium phosphate we have to use to deliver 31 ppm phosphorus.

We need to add 262 g of potassium phosphate monobed to get 31 ppm phosphorus. However, potassium phosphate also contains single-base potassium. We use the second equation to determine how much potassium should be added in ppm.

We add 39 mg K / l or 39 ppm potassium. Our recipe provides 210 ppm potassium. If we subtract 39 ppm of potassium from it, we see that we still have to add 171 ppm of potassium.

We have only one other source of potassium, namely potassium nitrate. Let's calculate how much we have to use of it.

We need to add 885 g of potassium nitrate to get 171 ppm of potassium. However, potassium nitrate also contains nitrogen. We use the second equation to determine how much nitrogen should be added in ppm.

We add 61 mg N / l or 61 ppm nitrogen. Our recipe provides 150 ppm nitrogen. We supplied 73.4 ppm nitrogen from calcium nitrate and had to add 76.6 ppm nitrogen. Now we can subtract 61 ppm nitrogen. We still have to add 15.6 ppm nitrogen. The only source of nitrogen that we have is ammonium nitrate.

Let us now calculate how much ammonium nitrate we have to use to deliver 15.6 ppm nitrogen.

We need to add 86.7 g of ammonium nitrate to get 15.6 ppm nitrogen.

At this point we have completed the nitrogen, phosphorus, potassium and calcium part of the recipe. For the other nutrients, we only need to use the first equation, since the fertilizers that we use for their supply contain only one nutrient in the recipe.

We need to add 498.5 grams of magnesium sulfate to get 24 ppm magnesium.

We need to add 18.9 grams of Sequestren 330 to get 1 ppm of iron.

We need to add 1.5 grams of manganese sulfate to get 0.25 ppm manganese.

It is easier to weigh small amounts of fertilizers in milligrams. The conversion from milligrams to grams is therefore carried out as follows

We need to add 692 milligrams of zinc sulfate to get 0.13 ppm zinc.

We need to add 0.17 milligrams of copper sulfate to get 0.023 ppm copper.

We need to add 2.8 milligrams of borax to get 0.16 ppm borax.

We need to add 0.12 milligrams of sodium molybdate to get 0.024 ppm molybdenum.

Summary:

Now all calculations have been completed. Now we have to decide in which storage tank, A or B, we give the individual fertilizers. In general, the calcium should be kept in a tank other than the sulfates and phosphates, as they can form precipitates that can clog the drip bodies of the irrigation system. Using this guideline, we can put the calcium nitrate in one tank and the monobasic potassium phosphate, magnesium sulfate, manganese sulfate, zinc sulfate and copper sulfate in the other tank. The rest of the fertilizers can be placed in both tanks.

You should also consider the amount of nutrients in irrigation water. For example, if we use irrigation water that contains 10 ppm magnesium, we only need to add 14 ppm more with our fertilizer (24 ppm Mg, which are required in the recipe, minus 10 ppm Mg in water). This is a great way to use nutrients more efficiently and fine-tune your fertilizer plan.

With some micronutrients, you have to decide for yourself what you want to add. You could do a small experiment to find out whether you need to add 0.12 milligrams of sodium molybdate to your stock solution, for example, or whether you are satisfied with the performance of your plants without this addition.

One last point to consider. Sometimes the calculations don't work as well as here for fertilizers that contain more than one required nutrient, and you may need to add more of a nutrient, than is provided in the recipe to provide the other nutrient.

For example, if you apply calcium nitrate to meet calcium needs, the solution may not contain enough nitrogen. In such cases, you have to decide which nutrient you want to give priority to. For example, you could apply calcium nitrate to meet the plants' nitrogen needs because the excess amount of calcium does not harm the plants. Or you choose to apply it based on the plant's calcium needs because the lack of nitrogen is just a few ppm.

Here you will find what problems there may be with a lack and excess of fertilizer

At this point we can give you recommendations for your plantations with modern analysis technology. Contact us...

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ID: 417

Cause: Soluble salt damage can be caused by over-fertilization, poor water quality, accumulation of salts in aggregate media over time, and/or inadequate leaching. Fertilizers are salts, and in hydroponic systems they are the most common fertilizer. As water evaporates, soluble salts can build up in aggregate media if they are not adequately leached. Irrigation water can also have high levels of soluble salts, contributing to the problem.

The symptoms: Chemically induced drought can occur when the content of soluble salts in the planting substrates is too high. The result is that the plants wilt despite sufficient watering. Other symptoms include dark green foliage, dead and burned leaf edges and root death.

Detection: Soluble salt levels can be monitored/measured by tracking the electrical conductivity (EC) of irrigation water, nutrient solutions and leachate (a nutrient solution drained from the plant container).

Correction: Soluble salts can be leached out with plain water. First, determine the cause of the high soluble salts level and correct it. 

The cause:  Strong temperature changes can interrupt and hinder calcium uptake. Lack of light, cold and/or too humid environmental conditions. Fertilizer level too low. Calcium deficiency can be caused by under-fertilization, a nutrient imbalance or a pH value that is too low. It is also related to moisture management, high temperatures and low air circulation. Calcium is a mobile nutrient and is transported through the plant in the water-bearing tissues. Fruits and leaves compete for water. Low relative humidity and high temperatures can lead to an increased transpiration rate and increased transport to the leaves. In this case, a calcium deficiency can develop in the fruits.

The symptoms:  The apical meristems (these are the dividing tissues of the plant) are deformed and die off without any noticeable symptoms on the oldest leaves. The upper part of the stem and flower bud may bend. Small and deformed leaves on the upper side. Unusually dark green leaves. Premature flower and fruit drop. After a deficiency, the leaves that were developing at the time of the deficiency often show a typical deformation/drying out or a white edge. This is called tip burn and is particularly common in lettuce and strawberries. Browning of the inside of a stem/head, around the growing point like in celery (black heart). Typical symptoms are also blossom end rot on peppers and tomatoes. Symptoms usually first appear as brown leaf edges on new plants or on the underside of the fruit. Blossom end rot in tomatoes and peppers. As symptoms progress, you may see brown, dead spots on the leaves. A lack of sufficient calcium can lead to rot.

Detection: Leaf analysis. Fruits have a poorer shelf life.

Correction :  Make sure the pH is between 5.5 and 6.5. Add calcium nitrate or calcium chloride depending on whether you need the extra nitrogen or not. 

In the greenhouse: Increase the temperature. More light. Without wind, the plant's nutrient transport is reduced - ensure air movement in the greenhouse. 

The cause:  Too little or incorrectly proportioned fertilizer. A pH value that is too low also blocks the absorption of sulfur. At a pH value of 4.0, sulfur absorption stops completely. Too little magnesium.

The symptoms:  Extensive yellowing  of the leaf tissue and the leaf veins. Often the younger parts of the plant first and later the whole plant. Symptoms are more likely to appear in young or freshly growing leaves at the top of the plant. Sulfur is an immobile nutrient. This means that sulfur can only be re-disposed (transported) relatively slowly by the plant. Lime green to yellow discoloration on leaves is characteristic of sulfur deficiency. It starts at the leaf stalk and moves to the leaf edges and tip. As the disease progresses, the entire leaves first turn yellow, then later brown and necrotic and then die completely. Sometimes purple/reddish leaf stalks on the affected leaves or even a purple stem. The symptoms of a mild deficiency are usually limited to the top of the plant. The middle part of the plant is hardly affected, lower leaves almost never.

Detection: leaf analysis.

Correction :  increase the fertilizer dose. Correct the pH: keep it well above 4.0. 5.5 to 6.5 is a good average for many plants. Enrich the soil with Epsom salt / magnesium sulfate / MgSO ₄ : one teaspoon per 2 liters of water (approx. 1% concentration).

Basics In hydroponics and the associated aquaponics, there are different methods to supply the plants with nutrients. These can be divided into active and passive systems. Passive systems have the advantage of being independent of the power supply. Their efficiency is lower than that of active approaches.   Passive and Active Hydroponic Systems Passive hydroponic systems are systems that function without a power supply. Active hydroponics uses pumps, aerators, humidifiers or spray nebulisers. These require electricity. Active hydroponic systems are more complex in design, but many times more effective in terms of plant growth due to the oxygen input.	Overview Wick Irrigation Ebb - Flood Systems NFT - Nutrient Film Technique DWC - Deep Water Culture DFT - Deep Water Nutrient Film Technique (Deep Flow Technique) Drip Irrigation Aeroponics - Mist from nutrient solution Aquaponics - Plant cultivation and fish farming Aquaponics - CHOP ( Constant Height, One Pump)   Schematic of an aquaponics system
A brief overview of the most common systems in aqua- and hydroponics
Passive Hydroponics: Wick Watering
The wick system (Wick Watering) does not require any moving parts or electricity. The plants are cultivated in a substrate that is supplied with the nutrient solution through the capillary action of the "wick". Supplying the plants via this system is not very effective. In addition, the wick can largely lose its nutrient transport properties due to mineral deposits. Another disadvantage is that no extra oxygen is supplied to the roots. The system is technically simple but plant growth is slower than with other active hydroponic systems. Pros: cheap purchase without electricity without technology low nutrient consumption low control effort   Cons: very low yield slow growth
Active Hydroponics: Ebb and Flood Systems
Ebb and flood systems (Ebb and Flood or Flood and Drain) use pumps (4) that flood the plants with the nutrient solution in a time-controlled manner (2). The plants are embedded in a net pot. After the pump is turned off, the excess nutrient solution is returned to the reservoir (1) via an overflow (3). Often a residual amount is left to make the system less vulnerable in case the pumps should ever fail, enough water remains in the plant basin as the overflow ensures a minimum water supply. By raising and lowering the liquid level (2), oxygen is introduced in the root area, which leads to more intensive plant growth. An electronic control system must adapt the ebb and flow rhythm to the requirements of the plants. Pros: low nutrient consumption low water consumption high yield in case of power or pump failure: no crop loss   Cons: high purchase costs power supply necessary Control effort
Active Hydroponics: NFT - Nutrient Film Technic
NFT or Nutrient Film Technic (NFT) systems provide a permanent flow of nutrients that flow around the roots in a thin "film". A pump conveys the nutrient solution to an inclined plane on which the plant roots lie, thus providing them with a continuous supply. The constant flow prevents nutrient build-up. NFT systems also add oxygen to the nutrient solution, for example through downpipes or intermeshing systems. The plant substrate is usually dispensed with, so that the roots have direct access to nutrients and oxygen and can thus grow quickly. A disadvantage is the loss of all plants in case of defective pumps or power failure. Pros: low nutrient consumption low water consumption very high yield   Cons: high purchase costs power supply necessary Control effort in case of power or pump failure: loss of harvest
Active Hydroponics: DWC - Deep Water Culture.
In deep water culture systems, also known as DWC systems, already rooted plants are placed in a net pot on a floating plate in the liquid reservoir, like a raft. To stabilise the plant, the net pot can be filled with substrate, such as clay balls. The roots hang directly in the nutrient solution, which is enriched with oxygen. This is done by means of an air pump and aeration stones that introduce very fine air bubbles into the water. Since the roots are constantly supplied with oxygen-rich nutrient solution, the plants grow very quickly and vigorously. The system is simple and safe, even in the event of a power failure nothing will happen to the plants. Thanks to the large water reservoir, the system can be left alone for a few days without having to worry about it. With the DWV system, the plants can also sit on a kind of raft and float on the nutrient solution. Pros: low nutrient consumption low water consumption very high yield fast growth (oxygen) in case of power or pump failure: no crop loss Cons: high purchase costs power supply necessary Control effort
Active Hydroponics: DFT - Deep Flow Technique (Deep Water Nutrient Film)
Active Hydroponics: DFT - Deep Water Nutrient Film Technique (Deep Flow Technique) The Deep Flow Technique, better known as DFT, is a variation of the NFT technique, also known as the Nutrient Film Technique. Instead of the thin nutrient film, the plants are flowed around by a nutrient solution about 2-4 cm high. The principle procedure is the same and works recirculatory. The deep flow technique DWT makes this cultivation system safer, because in case of pump failure the roots are still supplied. However, the method has hardly become established in the industry, because especially with longer / larger systems, the supply of oxygen to the plants varies and the plants grow unevenly as a result. It counts as one of the active hydroponics systems. Pros: low nutrient consumption low water consumption very high yield   Cons: high purchase costs power supply necessary Control effort in case of power or pump failure: loss of harvest
Active hydroponics: drip irrigation
With drip irrigation (drip system), the nutrient solution is dripped onto the substrate around the plants via a drip line. The nutrient solution flows past the roots and supplies them directly. The excess liquid flows off, supplying oxygen to the root area. Non-recovery system: In industrial cultivation there are non-recovery systems to achieve a high yield without measuring technology. Here, the plants are always supplied with fresh and equally adjusted nutrient solution. The nutrient is not returned to the cycle to avoid the spread of pathogens. This method uses more water and unused nutrients are lost. This system does not require control of nutrients but relies on experience with nutrient use. One can run the system "blind". Pros: very high yield fast growth in case of power or pump failure: no crop loss little control effort Cons: high purchase costs power supply necessary high nutrient consumption High water consumption   Recirculating system: The nutrient solution is fed back into the system, which means that only the nutrients that the plant actually needs are consumed. The flow rate is adjusted to the needs of the plants. Due to the closed system, however, it is necessary to control the nutrients in order to adjust them to the growth phase-dependent consumption. This system needs a regular control of the nutrient concentration. Pros: very high yield fast growth in case of power or pump failure: no crop loss Cons: high initial costs power supply necessary Control effort	Ohne Kreislauf                       Mit geschlossenem Kreislauf
Active hydroponics: Aeroponics - fog of nutrient solution
In an aeroponic growing system, the roots of cuttings or plants are not suspended in a liquid but in a mist of nutrient solution. The plants are hung with net pots in a chamber where the roots are sprayed or fogged with nutrient solution through water nozzles / fog nozzles. Aeroponic systems offer the optimal supply of the roots with everything they need to grow, they work very effectively and deliver maximum plant growth and therefore belong to the active hydroponic systems. However, the technical effort is high because of the high water pressure for the nozzles or the nebulisers used. In addition, technical measures must be taken to prevent the nozzles from clogging. A disadvantage is that a failure of the nebulisers is not tolerated by the free-hanging roots for a long time. Pros: very high yield fast growth   Cons: high purchase costs power supply necessary high nutrient consumption high water consumption Control effort
Active hydroponics: aquaponics - plant cultivation and fish farming
Aquaponics (aquaponic) is made up of aquaculture (fish farming) and hydroponics (plant farming), so two farming systems are combined. The excreta of the fish are used to supply the plants with nutrients, they are recycled and serve as fertiliser. The excreta are converted into nutrients that can be used by plants with the help of microorganisms. At the same time, the water is cleaned so that it can be returned to the fish tank and the fish have good living conditions. This creates a win-win cycle. In addition to growing lettuce and vegetables, fish are bred for food or ponds are kept clean with ornamental fish.	Fish farming can be combined with all systems that allow separation and control of nutrients through a circuit.
Active hydroponics: aquaponics - sump tank (CHOP: Constant high, one pump)
The decisive advantage of introducing a sump tank is that the height of the water level - especially in the fish tank - always remains constant. Only when water enters the fish tank from above through the pump does water flow back through the overflow. On the one hand, this means less stress for the fish and, on the other hand, the tank is filled with water even if the system fails (e.g. due to a burst pipe), as the water level can never drop below the overflow.

Overview of the most common systems

Passive hydroponics: wick irrigation
Active hydroponics: Ebb and flow systems
Active hydroponics: NFT - Nutrient Film Technology
Active Hydroponics: DWC - Deep Water Culture
Active Hydroponics: DFT - Deep Water Nutrient Film Technique (Deep Flow Technique)
Active hydroponics: Drip irrigation
Active hydroponics: Aeroponics - Fog from nutrient solution
Active hydroponics: Aquaponics - plant cultivation and fish farming
Active Hydroponics: Aquaponics - CHOP - Sump Container (Constant Height, One Pump)

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We are so used to plants growing in fields and gardens that we think anything else is completely absurd. But in fact: not only do plants grow without soil, they often grow much better when their roots are in water or very humid air instead. Growing plants without soil is called hydroponics. It may sound strange, but many of the foods we eat - especially vine tomatoes - are already grown hydroponically. Now here's a brief explanation of exactly how hydroponics works....

Plants grow through a process called photosynthesis, where they use sunlight and a chemical called chlorophyll in their leaves to convert carbon dioxide (a gas from the air) and water into glucose (a type of sugar) and oxygen. If you write this down chemically, you get this equation greatly simplified:

6 CO2 + 6 H2O → C6H12O6 + 6 O2 Carbon dioxide + water = sugar + oxygen   It turns out that the soil in which plants commonly grow does not appear in this formula at all. What plants need is only water, air and nutrients, both of which can be obtained from the soil. But if they can get these things elsewhere - for example, by standing with their roots in a nutrient-rich solution - they can do without soil at all. That is the basic principle of hydroponics.

In theory, the word "hydroponics" means growing plants in water (from two Greek words meaning "water" and "work").

Although the benefits of hydroponics are sometimes questioned, growing without soil seems to have many advantages. Some hydroponic growers have found that their yields are many times higher when they switch from conventional methods to hydroponics. Because plants grown hydroponically have their roots immersed directly in nutrient-rich solutions, they get the nutrients they need much more easily than plants grown in soil. With smaller roots, you can grow more plants in the same space and get more yield from the same area (which is especially good if you're growing in a confined space like a greenhouse or on a balcony or windowsill indoors). Hydroponic plants also grow faster. Many pests are transmitted through soil, so not using soil generally makes for a more hygienic growing system with fewer disease problems. As hydroponics is ideal for indoor growing, you can use it to grow plants all year round. Automated systems controlled by timers and computers largely automate the process.

There are also disadvantages: One is the cost of all the equipment you need - containers, pumps, lighting, nutrients and so on. Another disadvantage is the ponic part of hydroponics: it involves a certain amount of work. With conventional growing, you can sometimes be quite careless with the plants, and if the weather and other conditions cooperate, the plants will still thrive. Hydroponics, however, is more scientific and the plants are much more under your control. You have to constantly monitor them to make sure they are growing in exactly the conditions they need (although automated systems, such as timers for lighting, make things a lot easier). Another difference (which is arguably less of a disadvantage) is that hydroponic plants have a much smaller root system and so are not always good at supporting themselves. Highly fruiting plants may need quite elaborate support devices.

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