Plants, to grow healthy and abundant, need to be steadily fed and irrigated. Their nutrition takes place through fertilizers, substances containing chemical or organic compounds indispensable for plant growth. Fertilizers can supplement all stages of plant growth or only some parts at specific times of the year.

The need for a fertilizer ratio

The elements of the fertilizers are mainly nitrogen, phosphorus, and potassium. The fertilizer labels indicate them with the abbreviation NPK.

Each plant species require a distinct type of fertilizer and fertilizer ratio. In general, all fertilizers contain one or more elements useful for plant nutrition. Nitrogen(N), phosphorus(P), and potassium(K) are macroelements. Other crucial elements like iron, calcium, boron, zinc, manganese, etc. are microelements.

Both macro and microelements are essential in different stages of plant development from the first planting to flowering, until fruiting. To keep the vegetative process stable and not to damage or alter it, the various elements present in the fertilizers must be well balanced. They must contain an adequate percentage of chemical or organic compounds for that plant, also known as NPK ratio or fertilizer ratio.

Features of the NPK nutrients

Here is how to read the labels of fertilizers. First, here a list that explains the major NPK nutrients. Then, what the NPK numbers stand for when choosing the right fertilizer.

• N (Nitrogen) plays an influential role in the growth and regeneration of plants. It also acts on the leaf coloring. Without it, the plants cannot grow as they should, and the harvest would not yield the desired fruit. However, an excessive amount of nitrogen has negative effects. It can cause early flowering and ripening of the fruits, a greater fragility of the plant, a greater frequency of diseases, and pest infestations.
• P (Phosphorus) strengthens the roots, improves flowering, and is essential for photosynthesis. Therefore, it is an indispensable element in several stages of plant growth. From when it is born until the moment of flowering, plants need phosphorus. If the plant doesn’t get it, it will be more fragile. The leaves will change color, the roots will struggle to develop, and flowering will delay. Excess phosphorus is rare, yet possible: the plant will be damaged indirectly as the excess of phosphorus can lead to a deficiency of some micronutrients.
• K (Potassium) helps the plant to absorb water, thus contributing to its water balance. With the assimilation of this element, the plant will strengthen and develop a better resistance towards diseases and also extreme temperature changes. The potassium rate will determine the final flavor of the fruit. If present in minimal quantities, the plant will weaken, and in periods of drought, it will tend to breathe more and absorb less water. An excess of potassium will instead lead to a too high saline concentration and a lack of fundamental nutrients.

Each fertilizer displays and NPK ratio. What we see are the NPK numbers.

An NPK 10 -10- 10 fertilizer, for example, contains 10% nitrogen, phosphorus, and potassium, while an NPK 10-0-6 fertilizer contains 10% nitrogen, zero phosphorus, and 6% potassium.