Volcanic stones serve as fertilizer for plants

volcanic stone fertilizer

The volcanic rocks They serve as fertilizer for plants. It is known as volcanic gravel. It is a very porous and inert substrate and is usually between 5 and 15 millimeters in diameter. It has multiple purposes, commonly used as a decorative element and as mulch. In addition, it can also function as a suitable substrate for plants.

In this article we are going to tell you how volcanic stones serve as fertilizer for plants, their characteristics and how to use them.

Volcanic stones as substrate

volcanic rocks

Keeping plants in optimal health conditions and creating a favorable habitat for them depends largely on the substrate. In gardening there is a wide range of materials that can be incorporated into the soil, including volcanic gravel. You may already be familiar with tezontle, which is a specific type of volcanic gravel. In general terms, Volcanic gravel is available in large quantities and is cost effective.

Volcanic gravel serves as a beneficial substrate for plant growth. This gravel originates from volcanic activity and is formed by fragments between 5 and 15 millimeters in size. It is a unique substrate that serves as an inert medium for plant growth.

Volcanic stones are geologically known as igneous rock and are found in the vicinity of volcanoes and are formed from volcanic lava that cools quickly. Its natural origin and its rapid hardening process in air make it common on slopes and depressions.

The distinctive feature of this substance lies in the presence of numerous pores surrounding each granule, which is responsible for its unique properties. It is available in several granule sizes, with small or large size options.

Volcanic gravel comes in two shades: black and red, the latter being the predominant tone. In particular, it has an exceptionally light quality.

Although it lacks biological activity and does not participate in cation exchange, this substance is chemically inert, inorganic and aseptic. Despite these characteristics, it still offers numerous advantages for plants.

What advantages do volcanic stones offer plants?

volcanic gravel

Gravel serves a multitude of purposes, but one of the most frequent uses is to decorate gardens and pots. It not only acts as a protective cover but also adds a touch of aesthetic appeal. With its variety of colors, Gravel allows for the creation of captivating patterns, making it an ideal choice for decorative purposes.

To optimize the structure of the substrate, it is common practice to use small-grained gravel as a decorative element. By incorporating this gravel into the mix, the soil becomes airy and light. Additionally, the voids created by each granule aid drainage, preventing the buildup of standing water and ultimately reducing the risk of root rot.

Volcanic gravel, known for its exceptional porosity, has the ability to retain water. By integrating it into the substrate, irrigation intervals can be extended, ensuring optimal humidity levels and minimizing the chances of the plant becoming dehydrated. Additionally, when used as mulch, it effectively retains moisture beneath its surface.

Serving as a protective layer, Mulch protects against temperature fluctuations, preventing potential problems such as dehydration, erosion or degradation of soil structure. It also effectively mitigates erosion resulting from wind or excessive washing, which can displace soil. In addition, gravel mulch serves as an effective deterrent against the growth of unwanted weeds, ensuring the cleanliness and maintenance of our garden.

To meet the needs of certain plants that thrive in slightly acidic soils, it is advisable to introduce volcanic gravel into the substrate, as it will help acidify the soil. Azaleas, hydrangeas, pine trees, and Japanese maples are among the plant species that fall into this category. Promotes root growth and facilitates the establishment of robust roots and encourages the growth of a thriving root system.

Tips for using volcanic gravel


Before using the gravel for the first time, it is important to wash it thoroughly to remove any accumulated dust or dirt, ensuring its cleanliness and quality. We must establish the objective that we intend to achieve with this material. Using large volcanic gravel as a protective layer for the pots not only adds an aesthetic element but also serves a practical purpose. On the other hand, The inclusion of smaller volcanic gravel in the substrate mixtures is essential for preparation.

To cover pots, a layer is applied to the substrate mixture where the plant will reside. When used as a ground cover over large areas, it is very advantageous as it eliminates the need for grass or other high maintenance plants. Besides, It can be used on loose paving or to visually distinguish paths within garden designs.

A universal substrate is suitable for most plants, especially those without specific needs. To create this mix, combine equal amounts of worm castings and peat moss, then stir in a small amount of volcanic gravel. Mix all the components well for optimal integration.

To prevent root rot in pots that lack drainage holes, it is recommended to place a layer of volcanic gravel at the bottom of the pot. This layer will not only collect excess water but will also function as a reservoir, allowing water to evaporate back into the soil when needed.

To create an ideal environment for plants that thrive in high humidity conditions, you can use a tray filled with volcanic gravel. By pouring water into the tray and placing the flower pot on top, Water will evaporate near the plant, effectively increasing humidity levels.

Aquarium enthusiasts often choose volcanic gravel as a substrate for aquatic plants due to its ability to securely anchor plants in place, preventing them from floating and disturbing the desired design. Additionally, this type of gravel encourages the establishment of strong root systems, providing stability to new vegetation. It's important pointing that Volcanic gravel does not cause any harm to fish and does not interfere with the general parameters of the aquarium.

I hope that with this information you can learn more about how volcanic stones serve as fertilizer for plants.

Leave a Comment

Your email address will not be published. Required fields are marked with *



  1. Responsible for the data: Miguel Ángel Gatón
  2. Purpose of the data: Control SPAM, comment management.
  3. Legitimation: Your consent
  4. Communication of the data: The data will not be communicated to third parties except by legal obligation.
  5. Data storage: Database hosted by Occentus Networks (EU)
  6. Rights: At any time you can limit, recover and delete your information.