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Como abonar las plantas en macetas - Hortyjardín

How to fertilize potted plants

Solid fertilizers

How to fertilize potted plants

Fertilizing potted plants is different from plants located in the ground.

In this article you will discover how growing plants in pots is different compared to those grown in the ground, and the options available to fertilize them properly, easily and economically.

Plants that are in pots rather than in the ground, which is less natural. Differences exist? Which are? What implications does the use of pots have? Is fertilization different compared to plants growing in soil?

Limitations of pots

A pot is a closed container of limited size, usually small, that confines the roots and prevents them from spreading into a larger area, as occurs with plants that grow in the ground.

In this first paragraph are several key ideas for this section.

Small size

Regardless of the size of the pot, it will always be a fraction of the vast soil that covers most of the planet. In addition, pots are usually sized appropriately for the plant they contain, as larger pots are more expensive and difficult to handle.

This limited pot volume It requires that the substrate in which the plant is located be concentrated and balanced in nutrients , and that these nutrients be replenished each time the plant depletes them (since the roots cannot extend beyond the pot).


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Have you ever looked at the roots of a plant that has been growing in a pot for a while? For sure yes. Those tangled roots, twisting and turning around the container, are desperately seeking to expand into new territories.

This behavior of the roots is due to a reason: the nutrients (and/or water) in the potting substrate are no longer sufficient to supply the plant, or the available space is unbalanced in relation to the size of the plant. It must be taken into account that most plants maintain a balance between their aerial part and their roots. A cup with a diameter of 30 cm would correspond to a similar "root ball", although not as much due to the limitation of the pot.

We have seen the main limitations of pots in relation to plant nutrition, so now we will address the different options available for fertilizing them.

Options for fertilizing a pot

Fertilizing involves providing nutrients, and this can be done in various ways. Next, I will present some descriptive concepts that will facilitate the understanding of what I want to explain.

Replacement fertilization

When the substrate in a pot runs out of nutrients, it is common to replace it with another, taking the opportunity to transplant the plant to a larger pot, since otherwise the new substrate could not be added without damaging the roots.

In this case, a pot with exhausted substrate is replaced with another containing a new, nutrient-rich substrate. Additionally, since it is a larger pot, the roots can grow a little more and leave the initial confinement.

For the transplant you can use our Hortyjardín ® Potting Soil that comes ready to use

Additional fertilization

In this case, we are referring to the common practice of adding fertilizer to the potting substrate, either because it is enough or because you do not want to transplant it to another pot to replace the substrate.

Fertilizers that can be applied directly to the substrate of a pot can be solid or liquid.

  1. Solid fertilizers

This category includes the solid organic and inorganic fertilizers, also known as mineral or chemical fertilizers (the typical granular ones).

It is always preferable to opt for organic fertilizers (Humus or Manure), unless there is no other alternative and it is necessary to use a specific chemical fertilizer to quickly correct a specific deficiency.

Organic solid fertilizers, In addition to providing all the nutrients if they have been prepared correctly, they enrich the substrate with organic matter, which improves water and nutrient retention, very beneficial and necessary characteristics for a potted plant. They also provide microorganisms and improve the biological activity of the soil, necessary for the transformation and assimilation of nutrients by the plant.

To add these solid fertilizers, It is advisable to leave an empty space at the top of the pot so that a layer of one or two centimeters of organic fertilizer can be added periodically. With irrigation, this fertilizer will gradually break down and infiltrate into the roots, supplying nutrients to the plant.

This type of fertilization is slow release and must be applied before the plant needs it (1 to 2 months) and can last up to approximately 6 months, depending on the speed of transformation and assimilation.

As a last step in this section, it is recommended to lightly stir the surface of the substrate before adding the layer of solid fertilizer, and then cover it with dry leaves, pine bark, gravel or other similar material to protect and preserve it.

Liquid fertilizers

In addition to solid fertilizers that can be added to the surface of the substrate (water-soluble solid fertilizer), there is the option of using liquid fertilizers. (foliar fertilizer diluted in water and applied with a spray bottle to the foliage). We recommend our Nutrifol Foliar Nutrient 20-30-10 +em ®

What are the advantages of liquid fertilizers in pots?

They have an almost immediate effect, since they infiltrate to the root zone or are instantly absorbed through the leaves if applied foliarly.

They do not take up additional space in the potting substrate. It is important to be careful with salinization and not abuse its use.

They can be applied almost every watering (if properly diluted), which ensures good nutrition for the plant and allows us to forget about fertilization (since it is incorporated into the irrigation).

It is possible to make homemade liquid fertilizers that are of excellent quality, since they not only nourish, but also have other beneficial effects for the plant.

With this method I have verified that the plants respond almost immediately (in a few days) to fertilization, they remain vigorous and look healthy. Additionally, it is the easiest way to fertilize, as you only need to make the fertilizer once and then you can use it for many months, simply taking a little from the container and adding it to a watering can full of water.

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