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Hydroponic Nutrients: The Ultimate Guide

hydroponic nutrients

There is no one-size-fits-all when it comes to hydroponic nutrients. Each plant requires different nutrients in different proportions. This is the reason why, if you give every plant the same type and amount of nutrients, some will grow healthy while others will die.

Of course, there are other factors that can contribute to the “death” of your plant, including climatic conditions, but for the most part, wrong nutrients are the main cause. 

Hence, the need for an ultimate guide to Hydroponic nutrients. In this guide you will find everything you need to know concerning Hydroponic Nutrients to cultivate healthy hydroponic plants. 

Like humans, plants require both Macro and Micro Nutrients to grow healthy. Macro nutrients simply means large quantities of nutrients, while micro nutrients means small doses of nutrients.

Basic Hydroponic Nutrients

The basic nutrients plants need to grow are:

  • Oxygen
  • Carbon
  • Hydrogen
  • Nitrogen
  • Phosphorus
  • Potassium
  • Calcium
  • Sulfur and Magnesium;

And to a lesser extent:

  • Zinc
  • Boron
  • Iron and Manganese.

Of course, air contents most of these nutrients, water and soil, but hydroponic gardening means soilless cultivation. Hence, in order for plants to receive all the nutrients they need, other sources must be found including compost (decayed organic material) and fertilisers, especially liquid fertilisers. 

But first in our list, let’s look at the major elements needed by plants, including Cannabis, in order to grow.

Hydroponic Macronutrients

In the first place, the three (3) main macronutrients your Cannabis plant will need are Nitrogen, Phosphorous and Potassium (N-P-K). Usually, when purchasing fertiliser, you will notice some numbers such as 15-15-15. This means the solution contains 15% of each nutrient.  


In the same fasion, nitrogen is one of the most important elements of a plant as it is necessary for the process of photosynthesis, and the vegetativie growth of plants. E.g. The colour, leaves and stems. Nitrogen is usually applied to plant solution prior to the flowering stage and is used as part of the supplementary material, i.e., fertilisers and nutrient solutions in hydroponics.

Usually when plants are deficient in Nitrogen, you can tell by the yellowing of the leaves. However, it is harder to tell when plants have an excess of Nitrogen, as they could look vibrant and green. One eventual sign however, is their inability to bear fruits and flowers.


Coupled with the previous hydroponic macronutrients, phosphorus is also important as it helps plants transform solar energy into chemical energy and strengthens the immune system. It is the essential component of DNA, the genetic memory unit of plants, which is very important in tissue formation and cell division. Also, phosphorus plays a critical role in the development of flowering, fruits, seeds and roots.

For these reasons, your plants will require a large amount of phosphorus at the early stage of seedling, germination and flowering, but it’s also necessary throughout the Cannabis plants’ life cycle. Also, plants deficient in Phosphorous usually show abnormally weak leaves, flowers and roots.

On the other hand, an excess amount of Phosphorus prevents the plant from absorbing other elements such as Zinc, Calcium, Copper, Iron and Magnesium. 


Similarly, potassium is essential for the growth of plants but it is vital for protein production as well as the flowering stage of your Cannabis plant. Same, this is the reason why a large quantity is required and is classified as a macronutrient.

Contrary to other macronutrients. potassium does not form compounds in plants. However, it does help stir a variety of crucial processes including photosynthesis, starch formation, protein synthesis, and enzyme activation. Also, it is responsible for the movement of sugars and water in plant tissue and is vital for plant longevity.

As for example, cannabis plants that do not receive potassium enough, usually show yellowed leaves–similar to Nitrogen. Diametrically opposed, plants that are high in Potassium, no pun intended, usually are unable to interact with micronutrients. 

Hydroponic Micronutrients

About micronutrients, there are other essential nutrients to the growth of your hydroponic plant need in smaller quantities. Those receive the name of micronutrients. Some of these include Calcium, Sulfur, Magnesium. Zinc, Boron, Iron and Manganese. 

The chart below gives a graphical representation of the ranges in Hydroponic Nutrient Solutions for both macro and micronutrients.

Common Nutrient Ranges In Hydroponic Nutrient Solutions:

Common Nutrient Ranges In Hydroponic Nutrient Solutions


pH Of The Hydroponic Nutrient Solution

Hydroponically, the optimal pH range of the nutrient solution is 5.8-6.3. Micronutrients are more available in lower pH, but when pH levels drop below 5.5, you run the risk of micronutrients toxicity, as well as the unavailability of Calcium and Magnesium. 

Appropriate products for acidifying hydroponic nutrients are sulfuric acid, phosphoric acid and nitric acid.



Ammonium/nitrate is one of the major factors affecting the pH of the nutrient solution.

Suggested Nutrient Solutions for Various Crops:

suggested nutrient solutions


The Electrical Conductivity (EC) Of The Hydroponic Nutrient Solution

This is another important component of the process of hydroponic gardening. The electrical conductivity is a measure of the total salts dissolved in the hydroponic nutrient solution. It is used for monitoring applications of fertilisers. Important to note that the EC reading doesn’t provide information regarding the exact mineral content of the nutrient solution.

In closed hydroponics systems, the hydroponic nutrient solution is re-circulated, and elements that are not absorbed in high quantities by plants (such as sodium, chloride, fluoride, etc.), build up in the hydroponic nutrient solution, which makes it less effective..

In this case, you need more information about the nutrient solution content. And this cannot be provided by the EC. Testing the hydroponic nutrient solution frequently will help you decide on the timing for replacing the nutrient solution or diluting it with fresh water.

Water Quality

The hydroponic nutrient solution consists of minerals both in the natural water and the added fertilisers. 

The selection of fertilisers and their concentration in the hydroponic nutrient solution greatly depends on the quality of the natural water. It is therefore important to test the natural water before deciding on a fertiliser formula.

Minerals such as Calcium, Magnesium, Sulfur and trace elements such as Boron, Manganese, Iron and Zinc may be present in the source water. You need to take them into account in order to adjust your hydroponic nutrient solutions.

Additionally, natural water might contain high concentrations of unwanted minerals, such as sodium, chloride or fluoride, rendering it unsuitable for Hydroponics. This can be solved by diluting the water with a pure water supply or pre-treating the natural water with desalination or ion-exchange.


Traditional fertilizers work perfectly for growing your plant in the soil. However, in hydroponic gardening, all the nutrients your plant will need are already in the nutrient solution. These nutrients receive the name of macro and micronutrients based on the quantity required for healthy growth.

Major elements include Nitrogen, Phosphorus and Potassium, while micronutrients include Calcium, Iron, Manganese, Magnesium, Boron, Copper and Sulfur. 

Ammonium is a major factor affecting the pH levels of your hydroponic nutrient solution, while the optimal pH range of your nutrient solution should be 5.8-6.3. The electrical conductivity (EC) is a measure of the total salts dissolved in the hydroponic nutrient solution, and is used for monitoring applications of fertilisers. 

Finally, the quality of water is just as important as the Hydroponic Nutrients themselves, when preparing your Hydroponic Nutrient solution. The water must be tested and adjusted accordingly by treatment. 

And that concludes Hydroponic Nutrients: The Ultimate Guide. We hope you found this article useful. Did we leave anything out? Let us know in the Comments box below. 

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