Nitrogen deficiency (N)

Nitrogen deficiency manifests as slow plant growth and subsequently their yellowing to a pale yellow. Unfortunately, these symptoms can also be caused by a whole range of other negative factors (for example stagnant water, soil diseases, or nematodes, etc.).

So how can you tell when it is really a lack (deficiency) of nitrogen?

• Older leaves first begin to turn yellow-green – progressing from the top down
• Over time the yellowing reaches the lower part of the leaf and begins to spread into the veins
• Subsequently growth stops and the affected leaves drop
• Purple / reddish stem

Nitrogen deficiency can be recognized by the plant's yellow (yellowish) leaves: if the uptake of this element by the roots is limited, chlorophyll (essential for photosynthesis) disappears from the leaves. This happens first in the older leaves, at the lower part of the plant. The plant extracts nitrogen from these leaves and transports it to the young leaves and other places where it is needed for further growth. Eventually the growth of the plant halts and the leaves fall off. In some plants (e.g. cabbage) the leaves turn purple instead of yellow. Due to nitrogen deficiency plants, and their fruits, are considerably smaller. A plant lacking nitrogen is much more susceptible to damage from diseases and insects. These symptoms can unfortunately also be caused by a number of other negative factors (for example stagnant water, soil diseases, and also nematodes).

Causes of deficiency

Nitrogen deficiency can have several causes:

• Excess potassium, zinc and manganese in the soil or substrate.
• Excessive amounts of chlorides in the soil
• Soil or substrate contains too little nitrogen
• Too high a pH level in the root environment (around the roots)
• Dysfunction of the root system caused by damage, diseases or low soil temperatures
• Nitrogen is easily soluble and therefore is easily leached from the soil – which can cause its deficiency

How can nitrogen deficiency be prevented?

Usually nitrogen deficiency does not show up immediately and you need to wait for symptoms to appear. During periods of intense stress or growth the plant is more prone to deficiencies. It is definitely worth the effort to ensure you are using the correct fertilizers. Better fertilizers contain more than sufficient amounts of nitrogen and thus are able to provide proper nutrition for the plant throughout its growth.

By using basic nutrients that contain all the primary NPK components (Nitrogen N, Phosphorus P and Potassium K) you will reduce the likelihood of nitrogen deficiency. Always keep in mind that abiotic factors (such as: temperature, light intensity, acidity, humidity and wind strength) can also have a significant impact on nutrient deficiencies.

How to deal with the deficiency?

If you notice yellowing leaves on the plants, the situation can be addressed by applying high-nitrogen fertilizers. Nutrients can also be applied foliar (directly to the leaf) using foliar fertilizers.

What role does nitrogen play in the plant?

Nitrogen is absolutely essential for the plant. The plant needs nitrogen for the production of chlorophyll, which is indispensable for the process of photosynthesis. Nitrogen forms part of amino acids, from which proteins are then formed, and these are necessary for all processes in plants. In general, nitrogen supports the growth of plants, ensures higher quality of leaves and fruits, and further contributes to a larger yield volume.