Why is Vermiculite Better?

09 Jun.,2025

 

Vermiculite: main uses - Gardeners' World

What is vermiculite?

Vermiculite is a naturally occurring mineral (magnesium-aluminum-iron silicate) that is mined in various countries around the world, including the USA and South Africa. It gets its name from the Latin 'vermiculare', which means to breed worms, and the English suffix 'ite' which mean mineral or rock. When vermiculite is heated to very high temperatures, it expands into long strands resembling small worms.

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Vermiculite is lightweight, non-toxic and sterile and does not deteriorate over time. It has a neutral pH. It's used in the building industry, the car industry and in packaging. For use in horticulture, it's sold as lightweight, absorbent brown-gold flakes.

Vermiculite can absorb three or four times its weight in water and also attracts various plant nutrients such as potassium, magnesium and calcium. These qualities make it useful for propagation and for potting up plants that do best in moist compost, including house plants.

Vermiculite is sold in bags at the garden centre or online. Biological controls are often supplied in a small bag of vermiculite to make them easier to use. It is also used as an anti-caking agent in fertilisers.

How to use vermiculite

Vermiculite helps to aerate soil while simultaneously retaining water and nutrients, which it then releases over time. Vermiculite is therefore useful in seed sowing and propagation. It can also be added to house plant compost. You may find different grades of vermiculite flakes available – use the finest for seed sowing and the larger sizes for potting on, cuttings and house plants.

Seed sowing

Seeds of all sizes can be sown directly into 100 per cent vermiculite. Alternatively, you can use a 50:50 mix of vermiculite and seed sowing compost. You can also sow just using sowing compost, then cover the seed tray with vermiculite after sowing. Covering a seed tray with vermiculite helps to keep the compost moist and also helps to ward off the fungus that causes damping off. It also helps to insulate against temperature and humidity changes in the greenhouse.

Pricking out and cuttings

A mixture that contains around 30 per cent vermiculite is ideal for pricking out and potting on seedlings. It's also a good mixture for cuttings.

House plants

As vermiculite holds water and then drains like a sponge, it's great for adding to the compost of house plants that always seem to need watering, such as the maidenhair fern (Adiantum raddianum) and peace lily. The plant roots can take up moisture when they need it. As vermiculite takes a long time to dry out, you'll need to water less. Vermiculite also aerates the compost, which helps to stop it compacting or crusting over.

A 50:50 mix of house plant compost and vermiculite is ideal.

Vermiculite or perlite?

Perlite is expanded volcanic rock and looks like polystyrene granules. While it does help retain some water, it's primarily used to aerate compost. It's excellent for creating a free-draining potting compost for plants that need good drainage, such as cacti and succulents. It can also help create an airy compost for seedlings.

Vermiculite is better for water and nutrient retention than perlite and is best used for plants that need more moisture to grow. Vermiculite also protects seedlings against damping-off and other fungal diseases.

You can use vermiculite and perlite together – mixing a little perlite into a seed sowing mix will ensure plenty of oxygen gets to the roots, while a topping of vermiculite will lock the moisture in.

  • Perlite: main uses

Is vermiculite safe to use?

Yes. It's mined around the world according to the strict industry protocols. As with any gardening medium, it's best to wear gloves when handling vermiculite. Store in a cool, dry place away from weedkillers and other garden chemicals.

The company is the world’s best Lithium magnesium silicate supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

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Many years ago there was an isolated case of a mine where asbestos had developed alongside the vermiculite and contaminated it. These asbestos minerals are called Libby Amphibole Asbestos (LAA). This mine, located in Libby, Montana, USA was closed in .

Where and how to buy vermiculite

It's best to buy vermiculite that has been prepared specifically for horticultural use. Small and medium-sized bags of vermiculite are easy to buy at nurseries, garden centres and DIY stores such as Homebase, B&Q and Wilko. As it's very lightweight, it's easy to order for home delivery.

Where to buy vermiculite online

  • B&Q
  • Wilko
  • Marshalls

What Is Vermiculite and How Is It Used? - The Spruce

Vermiculite is a popular soil additive for houseplants and garden plants that improves soil texture and helps to grow healthy plants. The main benefits of adding vermiculite to soil are better water absorption, retention, and drainage of the soil, thereby regulating the amount of water available to plants.

Read on to learn what vermiculite is, how to use it, and how it compares to perlite.

What is Vermiculite?

Vermiculite is a mica-like mineral that serves as a soil amendment. It is mined out of the ground, exfoliated, and treated with extreme heat and pressure. The resulting worm-like, curly, and sterile product can expand.

The silvery-gray and flaky material is so light that the small particles move when you blow on them. Vermiculite traps nutrients in the soil, but it does not contain any nutrients itself. It has to be mixed with commercial fertilizer or compost to feed plants.

How Vermiculite Works in Soil

Vermiculite expands and is sterile. Its ability to expand lets it retain moisture in the soil, and its porous surface and unique shape trap nutrients for plants to access as needed. Vermiculite lightens heavy soils, providing a more conducive environment for plant roots.

Because it is sterile, gardeners don’t have to worry about it harboring harmful plant pathogens. Vermiculite won't deteriorate in the soil, meaning it lasts a long time.

Benefits of Using Vermiculite in Soil

Vermiculite is a useful addition to soil for various reasons:

  • It is lightweight, a property that is especially important for potted plants.
  • It is highly absorbent. Its particles absorb and retain water and nutrients and make them available to the plants whenever they need them.
  • It has a neutral soil pH, so gardeners don’t have to be concerned about altering the soil acidity by adding vermiculite.

Disadvantages of Using Vermiculite in Soil

When using vermiculite in soil, keep in mind the following cons:

  • Vermiculite is mined from the earth and is a nonrenewable resource.
  • It can be challenging to mix and distribute evenly.
  • It may be too porous, causing blockages in the soil or the entrapment of debris and algae.
  • Vermiculite emits irritating dust.

How to Use Vermiculite in Soil

This versatile mineral product has many different uses. They include: 

  • Improving drainage: Vermiculite is added to improve the soil texture of heavy clay soil that is waterlogged because of poor drainage. 
  • Improving water retention: Adding vermiculite also improves the soil texture of sandy soil that drains too fast and does not retain enough water. 
  • Seed starting: Vermiculite as the sole material or in a potting mix makes a good, lightweight medium for seed germination. It also benefits seedling development because water is available to the plants when they need it.
  • Addition to potting soil: Mixing vermiculite into the potting soil for container plants helps to improve drainage and moisture retention.
  • Soilless potting mix: Instead of buying a commercial soilless potting mix, make your own by mixing four to six parts sphagnum peat moss, one part perlite, and one part vermiculite. 
  • Rooting cuttings: Use vermiculite alone or with a lightweight, soilless potting mix to easily anchor new, tender roots.
  • Storing bulbs, root crops, and plants for indoor overwintering: Vermiculite makes an ideal storage medium as it absorbs any moisture that can cause decay.
  • Newly seeded lawns: A 1/4-inch layer of vermiculite helps keep grass seed from drying out while it germinates.

Vermiculite vs. Perlite

Perlite is a white material in soilless potting mixes that looks like little chunks of styrofoam. In its natural state, it has a pearl-like shine to it that accounts for the name, "perlite."

Vermiculite is valued because it retains water, and perlite is favored because it provides aeration. While vermiculite and perlite are two completely different substances, they do have some things in common. Both are:

  • Mined out of the ground (perlite is a volcanic mineral)
  • Heated, causing them to expand
  • Used as soil amendments, both in soilless potting mixes indoors and to improve garden soil outdoors
  • Lightweight
  • Sterile
  • Neutral pH
  • Nutrient-free

When to Choose Vermiculite vs. Perlite

The answer to the question of when to use vermiculite vs. perlite is straightforward. Use vermiculite for these applications that require extra moisture retention:

  • Dry plants: Add more vermiculite than perlite when mixing a growing medium for plants that dry out easily.
  • Seed starting: Choose the finest grade of vermiculite for seed starting indoors.
  • Root cuttings: Add more medium-grade vermiculite than perlite in a growing medium for root cuttings as it will be more conducive to root growth.