Rooting agents for the plants in our garden

The initial stage of development is vital for a plant. As a development, we initially look for an accelerated growth of the roots and a good quality of these.

In the current market we can find an infinite number of products that are positioned as rooting agents and not all of them are formulated from the same substances or nutrients.


The new roots are produced by a cellular development that initially creates a mass of white color with a great capacity for uptake of nutrients. Later, part of it is suberized (hardened and waterproofed) and no longer absorbs nutrients.

This first formation of roots is called absorbent hairs. They are known as hairs because they are very small in thickness, the size of a cell and very susceptible to “abuse.” Hence, it is recommended not to fertilize during the first weeks  and maintain a constant humidity, in order not to excessively increase the electrical conductivity of the substrate.

Hence the important use given to  amino acids as rooting agents, since they provide organic nitrogen (between 6 and 10% of general rule) and have a great assimilation by the plant.


As we have seen before, the conductivity in the root environment is important to be low so as not to damage the formation of absorbent hairs, which are usually very sensitive to the accumulation of salts and damage their growth.

Roots naturally tend to grow in areas with a lower concentration of salts. From an evolutionary standpoint, it makes sense and makes it easy to thrive in environments that can be hostile.

In many nurseries or nurseries where plants are produced, the conductivity of the root ball is usually increased and they recommend washing in the garden in order for the plants to concentrate roots in a more saline environment than the ‘outside’.

For this reason, the roots that are in development extend towards areas with less conductivity in the first weeks and this increases the rooting capacity of the plant .

Manually, we can prepare a nutrient solution rich in nitrogen and phosphorus, without providing much conductivity, and wet the root ball before transplanting.

However, we will have to know some additional data such as the conductivity of the nutrient solution and that of the garden where we want to plant. A conductivity meter can help us to get out of doubt if we want to try this experiment.


Phosphorus has always been considered an indispensable nutrient in the early stages of growth. This is because this element is responsible for the energy supply in the plant, known as ATP.

Phosphorus activates the metabolism of the plant and improves its energy efficiency. Hence, fertilizers rich in phosphorus are often used during several irrigations. An example can be the well-known 13-40-13, applied at a rate of 1 kg per 1,000 m2 of surface. This contributes 13% nitrogen, 40% phosphorus and 13% potassium.

However, organic matter, well decomposed, provides organic nitrogen that is useful in order not to excessively increase conductivity, since we have previously commented that it was a limiting factor in the creation and formation of absorbent hairs.

A very interesting and effective combination that is usually done is the following mixture. Measured for 1,000 m2 of surface and that can easily be adapted to the surface of your garden.

For every 1,000 m2 of surface, during 2 weeks of irrigation:

  • 1 kg of 13-40-13
  • 0.5 kg of ammonium nitrate (34.5%)
  • 1 L humic / fulvic acid

The 13-40-13 ratio does not have to be this way, it can vary. It is a well-known and widely used mixture that you can prepare at home if you have several fertilizers such as ammonium nitrate, monoammonium phosphate and potassium nitrate. It will be much cheaper.

It is done as follows if we want to prepare the equivalent of 10 kg of a 13-40-13 with simple fertilizers:

  • Ammonium nitrate (34.5%): 0.64 kg
  • Monoammonium phosphate (11-61-0): 6.55 kg
  • Potassium nitrate (13-0-46): 2.82 kg

We mix this and it is perfectly soluble in a water medium so we would have our 13-40-13 solution much cheaper than buying the complex.

We have already talked about the importance of phosphorus and nitrogen in the first weeks of development after transplantation, but what about humic or fulvic acids?

These, although many increase the electrical conductivity in the environment, if managed with the aforementioned dose (1 L per 1,000 m2), you control the contribution of salts and greatly benefit the physical, chemical and biological characteristics of the soil.

If you already have an important source of organic matter in the garden, you can save on adding these humic or fulvic acids.


Although phosphorus is the element that is considered most important in the formation of roots during the first weeks after transplanting, nitrogen is also important.

However, it must be borne in mind that its use should be limited in the early stages of development. Not because it causes a problem in the crop, but because there are still few roots and there will be a lot of nitrogen (especially the nitric form) that will percolate and contaminate aquifers .

The use of that 0.5 kg of ammonium nitrate per irrigation and 1,000 square meters of surface is enough, together with the rest of fertilizers, to make a managed and efficient use of nitrogen. Using a drip irrigation will be much more responsible and we will optimize the use of nitrogen. 

The  ammonia form (half of what we add in ammonium nitrate in terms of richness) promotes the formation of lateral roots, interesting to achieve horizontal root growth and better uptake of nutrients.

The  nitric form  (half of what we add in ammonium nitrate in terms of richness) stimulates the growth of those roots that the ammonia form has helped to create. This mixture complements very well to achieve good root development.

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