What is Vermiculite? How This Mineral Can Help Your Garden

Posted on

What is vermiculite?

This natural mineral is used in many sectors, from the building industry to gardening. It’s the common name for hydrated laminar magnesium-aluminum-ironsilicate. You can find out more about its geology at Mineral Galleries – Vermiculite.

Why is it helpful to gardeners?

You can use it to encourage seed germination and improve soil structure. This is because of its aeration and water-holding properties.


  • It’s a very lightweight material
  • Does not rot
  • Improves soil structure through soil aeration
  • Increases water and nutrient retention

Where does its name come from? It rings a bell…

You may be thinking of ‘vermiculture’, where worms are used to help decompose food waste. Both come from the Latin word ‘vermiculare’ meaning to breed worms.

This is because when vermiculite is heated, it expands into long strands resembling small worms. The American experimenter Thomas H. Webb first named it back in 1824. You can find out more in How Products Are Made – Vermiculite

Where and when should I use it?

You can mix it into composts and it’s great for hydroponic systems. Vermiculite’s insulating properties means it is particularly good when you need to cover seedlings.

What size should I get?

The smallest size of vermiculite is best used to germinate seeds. If you want to use it as a soil improver, opt for the largest size for the best results.

Video: How to mix vermiculite with your compost

It’s already in our ready-made composts – the shiny material is vermiculite. It’s easy to add it to your home-made compost too. Just take a look at this video:

Where to buy vermiculite

Would you like to buy some to encourage seed germination and improve soil structure? We sell different grades of Large, Medium and Fine. You can buy it online in 35 litre and 60 litre bags.

Not sure if it’s right for you?

Just give us a call on 01432 853111 or drop us an email at info@fertilefibre.com if you’d like more information.

Leave a Reply