Perlite and vermiculite: what is the difference?

Perlite and vermiculite are materials more and more used for crops because of their ability to provide a better and airy structure. However, many growers find it difficult to differentiate between them and to know what the possible uses of these compounds are. Therefore, we will explain the similarities and differences between perlite and vermiculite and find out how to use them.

Perlite and vermiculite: what are they?

Both are found in nature as well as in various products for cultivation. Although they are similar, it is advisable to know the characteristics and uses.

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Perlite

Perlite is a mineral derived from obsidian, a volcanic rock that forms when lava cools rapidly. By mixing it with water, you will obtain perlite. It’s a type of rock whose shape is very different from the commercial ones because the manufacturers heat them to expand them; in contact with heat, the water evaporates and then swells, giving rise to white and porous balls such as Boom Nutrients’ perlite.

Generally, it is used as a fertiliser for all type of pots, providing a lighter substrate that promotes more efficient drainage.

Perlite’s benefits for cannabis substrate and plants

Here are some characteristics of perlite:

• Reduces compaction: Its solid but perforated structure improves drainage and aeration, making it one of the best soil improvers.
• Promotes drainage: plants do not suffocate and can eliminate some pathogens, thus reducing the risk of waterlogging and suffering from fungal diseases.
• Neutral pH level. Neither acidity nor alkalinity is altered, so perlite does not block nutrients.
• Improves aeration. In addition to the various nutrients and water, the root system needs to breathe, which is why an exchange of gases takes place between the roots and the atmosphere. By using perlite, multiple air sacs are formed and provide the oxygen the plants need.
• Ideal for seed mixes or custom potting soils.
• Contains three to four times its weight in nutrient water.
• It is clean, sterile, odourless and non-toxic, however, it is advisable to use gloves and a mask when using it.
• Because it is light, it appears on the substrate.

Vermiculite: Characteristics

Vermiculite is a mineral belonging to the mica group which is formed by aluminium silicate, iron and magnesium. As with perlite, it is extracted from the soil and processed as an additive, producing products such as Boom Vermiculite. In this way, when it heats up, it can absorb 3 – 4 times its volume of water. It also absorbs and releases various plant nutrients such as potassium, magnesium, calcium and phosphorus.

This compound is mainly used for plants that require a lot of moisture and moist soil.

Advantages of using vermiculite for growing

• The ability to retain water and moisture reduces drainage and promotes more aerated soil while improving rooting.
• Provides nutrients to plants.
• Easy to mix with substrate
• Makes heavy soils lighter and more compact
• Clean, sterile and non-toxic as well as odourless.
• Perfect for use in hydroponics, as well as for starting seeds or creating your soil mix.
• Ideal for seed mixes or custom potting soils.

Differences between perlite and vermiculite

Both materials are suitable for improving potting soils, as they offer good drainage and retain moisture. In addition, they are acceptable for the propagation of new plants and for sowing both indoors and outdoors.

However, there are small differences between the two:

• The main difference is how the environment holds water and the amount of it. For example, perlite has a higher porosity, which allows for better drainage and aeration of substrates. Vermiculite, on the other hand, is more effective at retaining moisture.
• The uses are therefore different in the two cases. Perlite is considered a good choice for plants that require a dry growing place or for temperate and Mediterranean climates; whereas vermiculite is suitable for plants that require more moisture and is adequate for hot temeratures where the soil dries out quickly.
• Perlite can be used to loosen the substrate and break up soil compaction. Vermiculite can also be used for seedlings to prevent them from drying out during germination or for transplanting certain plants.

Despite these differences, perlite and vermiculite can be used together to allow plants to absorb nutrients in different ways. However, perlite or vermiculite cannot be used alone but should be mixed with other organic substrates.

Perlite and vermiculite are two compounds that are increasingly used by growers for the multiple benefits they provide. In summary, perlite should be used for better drainage and better airing while vermiculite for a higher humidity retention.