Any gardener knows that it is important to augment the soil with proper additives to ensure that their plants grow well. Among these supplements, Perlite and Vermiculite are two popular options. Since they are similar in many aspects, many DIY gardeners are not aware of the differences between Perlite vs Vermiculite.
Perlite and Vermiculite are additives used in the soil to aerate it. They are both inorganic, sterile products. Gardeners use both for water retention and nutrient retention in the soil. Moreover, they are naturally occurring ingredients commonly available in gardening stores.
While adding either of these is good for potting and gardening soil, they are often used together. Remember, Perlite and Vermiculite play slightly differing roles in enhancing soil quality and complement each other well.
In this article, we elaborate on Perlite vs Vermiculite, their uses, advantages, disadvantages, and commonly asked questions to help you determine which one is best suited to your requirements.
What is Perlite?
Perlite is an amorphous volcanic glass formed when obsidian comes into contact with moisture. For this reason, Perlite itself has a high moisture content. When heated, Perlite expands to a great extent. It is then crushed into small, white granules.
Perlite is lightweight, odorless, easily usable, and has a pH ranging from 6.5 to 7.5. For this reason, it can also be used as a sand substitute. It is also an excellent insulating agent.
Perlite is available as a super coarse grade, coarse grade, medium grade, and fine grade granules.
Few great gardening uses of Perlite are:
- This soil additive can retain an average amount of water and a low amount of nutrients. In soil mixes, it improves drainage by trapping moisture on its large surface area. However, this also means that it releases water much quicker.
- Soil humidity can be lowered by adding Perlite. The additive also helps reduce the density of potting soil, which results in low moisture retention. This is due to the fact that each perlite particle is composed of air cells that cannot absorb water. Hence, they hold water on the surface.
- Another use of Perlite is keeping the soil loose. It helps water and oxygen reach plant roots, making it the perfect additive for plant propagation from cuttings.
- Perlite also insulates plant roots from fluctuations in temperature. Used as a protective covering on some seeds, it is ideal for plants that need dry soil between watering sessions – such as succulents.
Advantages Of Perlite:
- Enhances soil drainage and aeration
- Promotes robust root growth
- Ideal for indoor plants requiring high moisture
- Works well with plants that thrive in dry conditions
- Reduces density of soil
- Reduces soil compaction
Disadvantages of Perlite:
- Low water retention
- Lightweight nature can cause it to get blown away
- Can cause dust exposure and allergies
- Considered a non-renewable resource
Other Uses Of Perlite:
- As a loose material to fill hollow concrete blocks for insulation
- To filter sediments and stormwater runoff
- Manufacturing plasters, ceiling tiles
What is Vermiculite?
Vermiculite is a silicate of magnesium-aluminum. Obtained from mines, this mineral product is processed to convert into a soil additive. It also has high water and nutrient retention properties.
Due to its water-retaining nature, Vermiculite is the perfect addition to plants that thrive in wet soil and require higher moisture levels, like many foliage plants. This property also makes the mineral a wonderful medium for seed-starters.
With a neutral pH of 7.0, the mineral can help raise the pH level of plants slightly.
Vermiculite is spongy and absorptive, so much so that it can absorb nearly three times its volume in water. However, this feature makes it unable to aerate soils equally well as Perlite.
Vermiculite may be one of two types: exfoliated or crude. Crude Vermiculite is golden and flaky, consisting of five different grades of particle sizes. On the other hand, exfoliated Vermiculite is the commercially available type. To produce exfoliated Vermiculite, crude Vermiculite is subjected to high temperatures, which cause it to expand into long, worm-like strands.
Ideal for hydroponics systems and germinating seeds, Vermiculite is a clean, sterile, non-toxic, and odorless soil additive.
Advantages Of Vermiculite:
- It does not turn moldy, rot, or deteriorate
- Increases potassium and calcium in the soil
- Retains nutrients and moisture for a long time
- Great medium for seed-starters
- Mixes easily with potting soil
- Improves soil structure
Disadvantages of Vermiculite:
- Can be too damp sometimes
- Optimal environment for bacterial and fungal growth
- Not a sustainable resource
- Often expensive and hard to find
Other uses Of Vermiculite:
- Used to line swimming pools
- For automotive paints or lacquers
- In gaskets and rubber seals
Perlite VS Vermiculite
In this section, we discuss which soil additive is best suited for which type of plant.
Both Perlite and Vermiculite are lightweight, sterile, odorless, and naturally occurring. They are used as sand substitutes for soilless potting mixes, which helps enhance aeration in potting mixes.
None of these two soil additives will rot or decompose. Both are used for seed germination and transplanting. Additionally, they are also used as components of fertilizers and pesticides.
Both are minerals used to retain water in the soil, but they cannot be used interchangeably.
There are several structural and functional differences between Perlite and Vermiculite.
- Structure: Vermiculite is a spongy silicate mineral that looks like mica and is brownish golden in color. On the other hand, Perlite is a porous, lighter volcanic glass that is granular and white.
Due to its structure, Vermiculite can hold three or four times the water. At the same time, Perlite only absorbs water on a surface level.
- Function: Vermiculite absorbs more water than Perlite due to its structure. Therefore, Vermiculite is used to keep the soil moist. Perlite is used to provide aeration and drainage to the soil.
Often, Vermiculite is used as seed starting media due to its high water retention capabilities. Perlite can work as a seed starting media as well, but only if there is rough room for additional drainage.
Perlite is a slightly alkaline medium, and Vermiculite is inclined towards a more neutral pH. Consequently, it is necessary to choose the medium which matches the soil’s natural pH most closely.
Which to Use: Perlite vs. Vermiculite
Depending on which plant you have, Perlite or Vermiculite may be used for soil compaction, aeration, and nutrient retention.
Perlite is commonly used in potting soil since it is an effective solution for enhancing drainage, reducing soil compaction, and enabling air to flow readily through the soil.
Vermiculite enhances the soil’s ability to store moisture and nutrients, allowing it to remain damp for longer and make more nutrients available to the roots.
Suppose you have plants that prefer dry environments, such as epiphytes, succulents, or cacti. In that case, Perlite will work best due to its superior aeration and drainage capabilities. When added to clay soils, Perlite can get rid of crusting and puddles. Moreover, Perlite reduces temperature fluctuations in soil and works well for soil compaction purposes.
Perlite can also increase humidity in plants, which makes it ideal for indoor plants.
Vermiculite, however, is best suited for plants that need wetter soils like touch-me-not. Not only does it help seed trays give rise to strong seedlings, but it also works as a permanent soil conditioner.
When it rains, Vermiculite will hold water until the soil begins to dry out and eventually release it at a desirable pace.
Commonly Asked Questions
CAN I MIX PERLITE AND VERMICULITE?
As Perlite and Vermiculite have varying functions, there is no requirement to mix them. Perlite is used to propagate root cuttings and aerate the soil for plants that need quickly draining soil. Vermiculite works well in germinating seedlings and holding moisture in the soil to keep it damp.
CAN PERLITE BE REUSED?
Perlite and Vermiculite are both reusable as they do not decompose or deteriorate. Remove the used Perlite or Vermiculite from the potting soil, extract any plant portions or root segments and rinse it. If you are worried about sterilizing the medium, use a 10 percent bleach solution diluted with water. Soak the Perlite or Vermiculite in the dilution for 20 minutes, and then rinse thoroughly.
CAN YOU MIX PERLITE WITH SOIL?
Yes. To use Perlite, mix it in with gardening soil or potting soil. For seed starting medium, mix Perlite with peat in a 1:1 ratio. This can also be used to propagate cuttings. You can even use just Perlite as is for this purpose.
For garden beds, add a two-inch layer of Perlite into the first six to twelve inches of soil. Potting soil only needs a third of Perlite in the soil mix.
DOES PERLITE OR VERMICULITE DECOMPOSE?
Since Perlite is made from superheated volcanic rock, it does not decompose over time. When you add Perlite to the soil, you permanently alter its texture and boost its robust plant growth suitability.
When used in potting soil, Vermiculite does not deteriorate or decompose. As a result, Vermiculite is a long-term solution to enhance and strengthen your soil.
DOES VERMICULITE HELP DRAINAGE?
Vermiculite helps retain moisture in the soil so that it can be used consistently for plants that need moisture. However, for plants that require a soil additive that provides good drainage and aeration, Perlite is a much better alternative.
IS PERLITE A STYROFOAM?
Many people tend to confuse Perlite with Styrofoam due to the similarity in appearance. However, Perlite is not Styrofoam and does not contain any percentage of Styrofoam in it. Perlite is a volcanic rock mineral.
DOES VERMICULITE CONTAIN ASBESTOS?
Vermiculite does not contain asbestos. Many people have the misconception that Vermiculite is available on the market with asbestos in it. Still, vermiculite mines are consistently tested for asbestos, and commercially sold Vermiculite does not contain any percentage of it.
IS VERMICULITE ORGANIC?
Vermiculite is naturally occurring but not necessarily always organic. When the mining and processing are done organically, Vermiculite can be labeled and sold organically. Therefore, look for packaging marked organic if you want to purchase high-quality organic Vermiculite.
IS VERMICULITE SAFE FOR GARDENING?
Yes. Vermiculite is a naturally occurring mineral that makes it completely safe to use gardening mixes and potting soil. As mentioned before, commercially sold Vermiculite contains no percentage of asbestos.
SHOULD I ADD VERMICULITE TO MY SOIL?
Suppose you require a soil additive that enhances the water and nutrient retaining capabilities of the soil. In that case, Vermiculite is the additive you need. Perfect for seed starting and germination, Vermiculite keeps soil damp and provides plant parts with vital nutrients to boost their growth.
WHAT IS PERLITE GOOD FOR?
Perlite excels at oxygenating soil and facilitating rapid drainage. As a result, Perlite is important for plant growth, especially in plants prone to root rot. Adding Perlite to your soil often boosts the moisture content, which several plants need to survive.
WHAT IS PERLITE MADE FROM?
Perlite is created from volcanic rock with accumulated moisture inside. That rock is then heated to an extremely high temperature and compressed until the accumulated water molecules react and form commercially available Perlite.
IS PERLITE GOOD FOR SUCCULENTS?
The drainage and air circulation perlite provide to the soil make it an excellent soil additive for growing succulents or epiphytes. For this purpose, you can combine potting soil, Perlite, and coarse sand in a 1:1:1 ratio. Its nature of drying out the soil between watering will help enhance the growth of dry soil-loving plants.
WHAT ARE THE TYPES OF PERLITE?
- Super coarse Perlite has particles ranging in size from 1/4″ and 3/32″ with a water retention capacity of 19%.
- Coarse perlite particles range in size between 3/16″ and 3/64″. It can retain 34% of water, but it is not preferred for gardening due to its size.
- Medium grade perlite has particles ranging in size between 1/5″ and 1/32″. Water retention capacity is around 46% for this type.
- Fine grade perlite has the smallest particle size, with pieces between 1/16″ and 1/128″ and a water-retaining capacity of 52%.
Conclusion: Perlite vs Vermiculite?
In a broad sense of the terms, Perlite and Vermiculite may be called the same thing as they have many similarities.
Either of these soil additives may be used depending on which plant you want to use them for. Both are effective and can be easily obtained from gardening stores.
Since they are both used for differing purposes, it is not about which one is better but rather which one you require. Hopefully, this guide has given you enough information about Perlite vs. Vermiculite.
Bonus: Thinking of getting new gardening equipment? Check out these gardening tools.