Hydroponic nutrients: what are they used for and how to dose them correctly?

Hydroponic nutrients: what are they used for and how to dose them correctly?

You have placed the seeds in their germination sponges. The reservoir is filled. The pump is running.

But if you are growing without soil, what does the plant feed on?

That is precisely the role of hydroponic nutrients.

In a traditional garden, the roots find some of the minerals they need in the soil and in what we add to it. In hydroponics, we remove soil from the equation: the nutrients must therefore be present in the water in a form accessible to the roots.

This does not mean you need to become a chemist to grow three basil plants in your kitchen.

For a home hydroponic garden, the most important rule is much simpler: use a solution designed for hydroponics and follow its dosage rather than adding "a little more so it grows better".

What are nutrients used for in hydroponics?

A plant does not live on water and light alone.

To build its tissues and ensure its growth, it uses different minerals. Hydroponic nutrient solutions provide nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur, as well as micronutrients needed in much smaller quantities, such as iron, manganese, or zinc. Oklahoma State University precisely documents these different elements in hydroponic solutions.

The principle is therefore quite easy to understand:

light provides energy; water carries the nutrients; the roots absorb them.

Without an appropriate nutrient supply, a plant can sometimes start thanks to the reserves contained in its seed, but it will not have everything it needs sustainably to continue normal growth.

Water alone therefore does not replace a nutrient solution.

Can you use a regular plant fertilizer?

It is better to use a product specifically designed for hydroponic cultivation.

Not all fertilizers are formulated to work in the same way.

In a soil pot, the soil plays a role in the exchange between water, roots, and minerals. In a hydroponic system, the roots are directly exposed to the nutrient solution.

A hydroponic formulation is designed to provide the elements in forms compatible with this method of cultivation.

This is also why it is not recommended to improvise a recipe from several household products.

Professionals can make their own nutrient solutions from different mineral salts and precisely adjust their composition. Penn State, for example, publishes calculation methods intended to prepare hydroponic solutions from several fertilizers.

For three lettuces on a countertop, this complexity does not add much.

A ready-to-dose hydroponic solution is much simpler.

Why are there A + B nutrients?

If you start hydroponics, you will quickly encounter bottles called A and B.

It is not because the plant needs two different meals.

Some substances used in concentrated nutrient solutions can react with each other when stored together at high concentrations. Manufacturers therefore separate the formulation into two parts.

Once sufficiently diluted in water, they together make up the nutrient solution intended for the plants.

For the user, the procedure remains simple:

1. fill the reservoir with the required amount of water;
2. add the amount of solution A indicated by the manufacturer;
3. mix;
4. add the recommended amount of solution B;
5. mix again.

Always follow the instructions of the product you are using.

Concentrations are not universal. A dose valid for one brand should therefore not be automatically applied to another.

Do more nutrients make it grow faster?

No.

This is probably the most important mistake to avoid.

If a plant needs nutrients, it may seem logical to think that doubling the amount will speed up its growth.

In reality, an excessive concentration of nutrient salts can cause osmotic stress, imbalances, and toxicities. Conversely, too low a concentration can lead to deficiencies and reduced growth.

The right dosage is therefore neither "as little as possible" nor "as much as possible".

It is the concentration suited to the plant and the system.

In a home garden, start with the recommendations of your nutrient manufacturer. Do not correct a plant that seems to be growing slowly by arbitrarily pouring in more solution.

The cause may be elsewhere: insufficient light, temperature, roots in poor condition, a naturally slow variety, or simply the growth stage.

What is EC in hydroponics?

As you continue your research on hydroponics, you will probably eventually encounter two letters: EC.

EC stands for electrical conductivity.

Hydroponic nutrients consist of mineral salts that form ions when dissolved in water. These ions allow the water to conduct electricity better.

Measuring this conductivity therefore gives an indication of the overall amount of dissolved salts in the solution. A high EC generally corresponds to a higher concentration; a low EC to a lower concentration.

Oklahoma State University generally indicates an EC of 1.5 to 3 dS/m for hydroponic cultivation, but the optimal value depends on the crop and the context.

This last point is essential.

Do not take "1.5 to 3" as a universal instruction to blindly apply to all your plants.

A lettuce, a basil, and an adult tomato do not have exactly the same needs.

Should you measure the EC in a small indoor garden?

Not necessarily to start.

If you use a nutrient solution designed for hydroponics, correct water, and the dosage indicated by its manufacturer, you can perfectly discover hydroponic cultivation without immediately buying a conductivity meter.

EC becomes especially interesting when you want to better understand what is happening in the reservoir.

For example:

you are growing several demanding plants;

you regularly observe problems;

you want to adjust your solution more precisely;

or you want to go further in mastering your garden.

In this case, a conductivity meter allows you to no longer reason solely in the number of milliliters poured.

It gives you a measure of the overall salt concentration of your solution.

Be careful, however: EC does not tell you which elements are present.

Two solutions can show similar conductivity while having a different mineral composition.

It is an indicator, not a complete analysis of the water.

And what about pH in all this?

pH measures the acidic or basic character of a solution.

Why is this important?

Because it influences the availability of different nutrients for the roots.

Oklahoma State University generally places the hydroponic nutrient solution in a slightly acidic zone, around pH 5 to 6, and explains that an unsuitable pH can reduce the availability of certain nutrients.

Other technical references use slightly different ranges depending on the systems and crops; one publication dedicated to aquaponic systems gives, for example, an acceptable range of 5.5 to 6.5 for hydroponic crops.

Again, the goal is not to turn your kitchen into a laboratory.

If your plants are growing normally, do not spend your day changing the pH to gain a tenth.

However, a persistent growth or deficiency problem despite correct nutrient dosing may justify checking the pH of the water.

Why does the nutrient level change over time?

Your reservoir is not a closed bottle.

Plants absorb water and different minerals at rates that change according to their size, species, and growing conditions.

Water can also be lost through evaporation and transpiration.

This means that regularly adding the same amount of nutrients without thinking is not necessarily the right strategy.

Imagine that the reservoir level drops.

You do not know simply by looking at the water if the plants have absorbed the nutrients in exactly the same proportions.

This is one of the reasons why professional systems monitor EC and pH and periodically renew their nutrient solution.

Oklahoma State University recommends, in its technical guide for solution management, a complete replacement about every two weeks to prevent the proportions between the different elements from gradually drifting.

For a home device, the system manual and the nutrient manual remain however priority: reservoir volume, circulation type, and consumption rate can differ.

Should you add nutrients every time you add water?

Not necessarily.

This is precisely a possible mistake.

If the level drops because the plants have mainly consumed water, systematically adding a full dose of nutrients can gradually concentrate the solution.

Conversely, indefinitely settling for adding only water can end up making the solution too poor.

The right method therefore depends on the product and system used.

To start:

follow the dosing protocol provided with your nutrients, monitor your plants, and renew the solution according to the maintenance recommendations of your installation.

If you want to manage the supplements more finely between two renewals, that is precisely where an EC measurement becomes useful.

How to recognize a nutrient problem?

A plant can signal that it is not growing in good conditions.

Yellowing leaves, browning edges, slowed growth, or an unusual appearance can sometimes be linked to nutrition.

But beware of a too quick diagnosis.

A yellow leaf does not automatically mean "nutrient deficiency".

The problem can also come from the roots, light, pH, temperature, or simply the normal aging of a leaf.

Adding a strong dose of nutrients "just in case" therefore risks worsening the situation.

Before correcting, check in this order:

• the level and condition of the water;
• the dosage you actually used;
• the condition and smell of the roots;
• the light received by the plant;
• then, if necessary, the EC and pH.

This little step avoids many unnecessary corrections.

Are Belverdia nutrients mandatory?

No.

This is an important point in the logic of Belverdia gardens: the system is not designed to lock you into proprietary consumables.

You can choose your seeds and use germination sponges and growing baskets compatible with your device. For nutrients, you can also use a suitable hydroponic solution while following its instructions.

→ Discover Belverdia hydroponic gardens

How to dose your nutrients when starting?

You can follow a very simple method.

Start with water suited to your use and fill the reservoir to the indicated level.

Then dose your hydroponic nutrients exactly according to the manufacturer's instructions, taking into account the actual volume of water.

If you use an A + B solution, add the two components according to the provided protocol rather than mixing them directly in concentrated form.

Then observe your plants.

And above all, resist the temptation to correct every variation by adding more product.

When you will be comfortable with this routine, you can start measuring the EC and eventually the pH if you want to steer your cultivation more precisely.

→ Download the guide for free

What to remember

Hydroponic nutrients replace part of the role that soil naturally plays in traditional cultivation: they bring the minerals necessary for the plant to the water.

But more nutrients do not mean more growth.

A good start simply consists of choosing a solution suited for hydroponics, following its dosage, and observing your plants.

EC and pH then allow you to go further.

They are very useful for understanding and adjusting a nutrient solution, but they should not give the impression that home hydroponics requires a complete laboratory from the first seed.

Start simple.

You can always become more precise when your plants — or your curiosity — give you a good reason.