Lava Rock for Plants

To help us understand how lava rock and be used in your home and garden, we need to know more about what it is. Here are some of the properties of lava rock to help you better understand:

• Lava rock or volcanic gravel is fragmented volcanic rock which usually comes in individual stones of around 5 to 15 millimeters in size. However, this will depend on how it has been processed. It can serve as an inert substrate for plants.
  
  
• Lava rock is of natural origin. Specifically, it is formed when volcanic lava hardens rapidly in the air, which is known as igneous rocks in geology. For this reason it is found on slopes and depressions near volcanoes.
  
  
• Its main characteristic is that each piece is covered by multiple pores. It is from this fact that many of its benefits to plants are derived.
  
  
• There are two colors of lava rock which are black and red. Red is the most common, although this depends on availability.

• It is very lightweight.
  
  
• It is chemically inert, inorganic and aseptic. This means it does not have any biological activity, nor does it play a role in cation exchange. However, it has a host of benefits for plants.

If you would like to buy lava rock for plants, you can find a great option below:

Now we know what is lava rock and some of its important properties, we look at some of the benefits of lava rock for plants:

• Decorate pots and gardens: this is the most common use of volcanic gravel. It is used as a cover and as a way of decorating pots. Since there are different colors, interesting patterns can be made with them.
  
  
• Structure the substrate: although it is usually used more for decoration, incorporating small-grained gravel into substrate mixtures will help keep the soil airy and light.
  
  
• Drains the soil: the recesses formed by each granule will help prevent water from remaining pooled in the soil and help to avoid root rot in the process.
  
  
• Retains water: lava rock is the most porous of all volcanic gravel and can retain water. Incorporating it into the substrate will help to avoid damage to the plants, maintain good humidity and reduce the risk of the plant drying out. If mulched, it will also retain moisture undeneath the plant.
  
  
• Protects against temperature changes: used as a mulch, it helps to insulate the layer underneath against changes in temperature. Such changes can cause dehydration, erosion or loss of soil structure.
  
  
• Controls erosion: when used as a top layer, lava rock reduces erosion caused by wind or excessive washing that repositions the soil.
  
  
• Prevents settling of unwanted weeds: mulching is often used as a technique to prevent unwanted weeds from growing, so using gravel as a top mulch will help keep our garden clean.
  
  
• Slightly acidifies the soil: some plants prefer slightly acid soil. For these purposes, it will be good to incorporate lava rock for plants into the substrate. Some examples of these plants include azaleas, different types of hydrangeas, pine trees or Japanese maple.
  
  
• Promotes rooting: stimulates the development of strong roots and a healthy root system.

To begin with, lava rock should always be washed before it is first used. This will help to ensure that it is free of dust and dirt buildup. We then have to define the purpose for using this material. The large volcanic gravel is most commonly used as a mulch to cover the upper part of the pots and flowerbeds. This also has a decorative function, while finer lava rock for plants is incorporated into the mixtures to prepare the substrate.

To use as a mulch, it is simply placed on top of the soil. Here are two possibilities when using lava rock for plants:

• As a cover in pots: a top layer is placed over the mixture of the substrate where the plant will be placed.
  
  
• As ground cover or larger areas: it is very useful for covering large areas of land without having to place grass or other plants that require care. It can also be seen in loose pavements or to visually differentiate paths within garden design.

To use as a substrate it can be incorporated in the following ways:

• Universal substrate: this is appropriate for most plants or for those that do not have special requirements. To prepare the mixture, use equal parts of homemade earthworm castings and peat. Then mix in a handful of lava rock. Mix everything well to integrate.
  
  
• Substrate for bonsai: bonsai require special substrates to maintain good oxygen levels in the roots and avoid waterlogging that trees dislike so much. For this case, a mixture of 30% lava rock and 70% akadama can be used. Learn more about this substrate with our article on what is akadama soil for bonsai?
  
  
• Volcanic gravel for cacti and succulents: the substrate for different types of succulents and cacti must be special so that it does not retain too much water. To take advantage of lava rock for these plants, 2 parts of universal substrate should be mixed with 1 part of volcanic gravel.

Finally, there are other uses that can be given to benefit our plants:

• For pots without drainage: pots without a hole retain water and are prone to root rot. To avoid this, a lower layer of lava rock can be placed on the bottom of the pot so that all the water collects here. In addition, it will serve as storage water that can be evaporated back to the ground if it runs out of water later.
  
  
• Tray for environmental humidity: there are plants that require high environmental humidity. To promote it, you can prepare a tray with volcanic gravel to pour water and place our pot on top of it. The water in the tray will evaporate near the plant and provide moisture.
  
  
• For aquatic plants: lava rock is widely used as a substrate for aquariums that have plants because it serves as an anchoring medium to achieve the desired design without the plants floating around. It also promotes rooting to stabilize the new vegetation. It is not harmful to fish and will not interfere with aquarium parameters.

Now that you know about the properties, benefits and uses of lava rock for plants, you may want to know about substrates in general with our guide to the differences between compost and fertilizer.

If you want to read similar articles to Lava Rock for Plants, we recommend you visit our Plant care and cultivation category.