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Why is fertilizing with nitrogen important?

Written by Han van der Kooij | Last update: 22-6-2021

Nitrogen is an item, a lot of attention is given to within the horticultural sector. This element is needed by the plant, besides the other head and trace elements. But what exactly does nitrogen do? Why is it so important to your crops? And in what forms can nitrogen be added to your crop? Our fertilizer specialist have provided an explanation below. 

What is nitrogen?

 Nitrogen (N) is an element, which is also found in the atmosphere. The human body does not need the nitrogen we breathe in, but plants do need this important element. This is why in horticulture, extra nitrogen is added to the plants.

Why fertilize with nitrogen?

Nitrogen is crucial to plants, especially in the growth phase (vegetative phase). The cell elongation and development of leafs can be thanked to this nutritional element. Mainly during the growth phase, cultivators make the decision to add extra nitrogen through fertilizers. 
Furthermore, nitrogen is essential in the process of photosynthesis. Nitrogen is needed by the plant in order to transfer it to chlorophyll. With the presence chlorophyll, the process of photosynthesis can take place, in which carbon dioxide is converted into oxygen and glucose.

Nitrogen surplus

Just like all the other nutritional elements, the input of nitrogen must be limited. When a nitrogen surplus occurs, the risk for diseases, limp and dark green leafs increases. In addition, extensive growth and later ripening of the product, are symptoms which are in line with a nitrogen surplus.  

Nitrogen deficiency

Noticed yellow or light green discoloration of the older leafs? Remarked a brake in the plant’s growth, or a sudden increase in the volume and growth of the roots? These could be indications of a nitrogen deficiency. 

Basically, a nitrogen deficiency can occur in any plant. This can be remarked by a brake in growth, the falling-out of leafs and stalks that turn red or purple.

A nitrogen deficiency can be caused by various factors. A surplus of potassium, zinc or manganese in the soil or substrate could lead to a serious deficiency, as well as an excess amount of chloride.
The root environment not functioning properly, as a result of damage, diseases or low temperatures, are factors which should be taken into account when a nitrogen deficiency is noticed. 
A deficiency can be solved by adding extra nitrogen to the plant. This can be done through several sources. 

What sources of nitrogen are there?

When urea is added to the plant, it has to be converted into nitrogen by the soil life, in order to be available to the crop. It is discouraged to make use of urea products, when soil life is not present (e.g. in substrate). This, since it must perform an essential process, before the plant can actually make use of this nutritional element. Lastly, it is important to keep in mind, urea does not have an EC.

Just like urea, ammonia is an indirect source of nitrogen. Ammonia also needs a conversion by the soil life, before the plant can take in the nitrogen. A product such as ammonia nitrate can be added to the fertilization scheme in order to fulfill the plant’s need for nitrogen. 


Unlike urea and ammonia, nitrate is a direct source of nitrogen, meaning the nitrogen is available to the plant the moment it is added. Potassium nitrate 

can be used to offer nitrogen to the plant. It can be dissolved easily, however rinses out quickly.

What product is suitable for me? 

The sources of nitrogen listed above, vary from each other. This also leads to different preferences of cultivators. One might be satisfied with the use of urea, while the other would rather make use of a direct source, like nitrate. 

Are you growing your crops on substrate? Then we recommend to make use of nitrogen in the form of nitrate, since this is the only source that is not depending on the conversion of the soil life. In general,  no use of the soil life is made in substrate cultivations. 

Are you growing your crops in soil? Then we advize nitrate, urea and ammonia. The soil life will be responsible for the conversion. If your crop is sensitive to ammonia, it is better to choose urea as a source of nitrogen. 


Any questions about fertilizing with nitrogen?

Do you have any questions about a nitrogen deficiency, surplus, or about other deficiencies? Do you want personal advice? Contact one of our product specialists, or use the form below. 

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Han van der KooijAbout Han van der Kooij

Han van der Kooij, fertiliser product specialist at Royal Brinkman, understands the customer like no one else. After being a grower himself, for 26 years, he knows the ropes and is aware of what is involved in being a grower. Converting his own knowledge and experience into recommendations that are useful to growers, is what he likes best about his job. "Finding that this leads to good results, makes me quite satisfied."

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