Perlite for plants: what is it, what is it for and how is it used

Perlite is one of the most useful materials to use in gardening, and practically any soil or substrate welcomes the addition of this light volcanic mineral. It is a very common and easy to find element, which is also not expensive.

If you want to learn what perlite is for plant substrates, join us in this article where you will find a practical guide on what perlite is for plants, what it is for and how it is used , among other useful details for fans. to gardening.

What is perlite for plants

When we ask ourselves what is perlite for substrate , first of all we must differentiate it from the perlite that was used a few years ago in construction, although it has already fallen into disuse. In fact, originally the material was not used in gardening, but amateurs soon discovered the advantages of its application.

Perlite is an amorphous volcanic glass with a water content of between 2% and 5%. Due to this moisture content, when it is heated to high temperatures it undergoes an expansion process in which it multiplies its size by up to 13 times, giving rise to the light-colored, porous and very light material used in gardening and horticulture.

It is a material for the substrate of plants that is cheap, light, pH neutral and inert, so it does not react with any element in the soil or alter its balance. In addition, perlite does not carry pests or diseases of any kind, so it is an element of easy access and great advantages in its use.

Perlite for plants: what is it, what is it for and how is it used - What is perlite for plants

What is perlite for plants?

The benefits of perlite for plants are very numerous.

  • Its porous texture and its so light weight favor the aeration of the soil, making it difficult to caking it and, therefore, facilitating the access to oxygen and its development for the roots of the plants.
  • In addition, perlite helps to retain a certain level of moisture to the substrate, favoring the slow release of water more gradually, as well as other elements such as fertilizers.
  • Despite its ability to partially retain moisture, perlite also improves soil drainage, preventing puddles that are so harmful to practically any plant.
  • Used as padding, it helps to isolate the floor from extreme temperatures in very hot climates, since its characteristics make it reflect a high amount of light. This also causes the plant to have greater access to it, and even helps to ward off pests, insects or fungi that need darker and more humid environments to develop. 

How to use perlite for plants

The use of perlite for plants is very simple. The most common is to use perlite substrate , that is, add the perlite to the substrate in different proportions to achieve the desired effect according to the crop to be planted and its needs. These are its main uses in gardening:

  • It is often used as a propagation substrate , added to mixtures with peat, worm castings, and coconut coir. These components give rise to a substrate of excellent conditions: very light, rich in nutrients, with great drainage and good aeration, making it ideal to provide an ideal environment for plants in the early stages of their growth.
  • Perlite is also commonly used in hydroponic crops , since its porous texture helps retain nutrients, in addition to providing elements such as silicon by itself.
  • In very caked outdoor soils, it is common to add perlite after stirring and aerating them well, to prevent them from becoming excessively compacted.
  • It is especially suitable for succulent plants , in which case we will mix it with the sand or gravel that is usually used with them, thus making the mixture lighter. 
  • It is also common to use perlite mulches to protect the soil from excess heat and prevent the proliferation of weeds in outdoor crops. In these cases, the soil around the plants to be protected is simply covered with a layer of one or two centimeters of perlite, so that it acts as insulation.

It is important to moisten the perlite before handling it to work with it and mix it with the soil, since, being so light, it is common for dust to rise and we end up breathing it, something that is not convenient. Another option is simply to wear a mask.

Perlite for plants: what is it, what is it for and how is it used - How is perlite used for plants

What can be used as a substitute for perlite

Perlite is very commonly used in conjunction with other materials such as vermiculite or tepojal. These have very similar but slightly different properties, so there are those who prefer to use one of the three, and there are those who choose to mix them to receive the good of each one.

  • Vermiculite , for example, also aerates and lightens the soil, but has a somewhat higher moisture retention capacity than perlite, so it is common to use it in tropical plants or those that require higher humidity in the substrate. 
  • Tepojal is somewhat heavier than perlite and offers somewhat less oxygenation and drainage, although it offers the advantage of mixing better with the substrate given its greater weight. 
  • Coconut fiber also fulfills a role similar to these volcanic rocks, helping to lighten the substrate and improve its drainage and properties, which is why it is often combined with these. 

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