By the urban gardener

Australia's online hydroponics supplies & indoor grow shop

Hydroponics implies growing of the plants without soil; however, they still need medium to grow in. Hydroponics stores online or local ones offer a wide range of mediums to choose from, and it is better to know them to make the optimal choice.

Different Types of Growing Mediums

Although almost any substances can more or less serve as the growing medium, the most popular are those named below:

- Water / Air / Sand / Gravel

- Vermiculite / Perlite

 - Lava Rock

 - Sphagum Moss / Sawdust

 - Expanded clay pellets

 - Oasis Cubes

 - Coconut Fiber

 - Fiberglass Insulation

 - Proprietary Soilless Mix

 - Rockwool

Although rockwool is the last in the list, it can definitely be named the most popular growing medium among hydroponics gardeners, because it is easy and cozy to use.

Rockwool was initially used as insulation material in building. However, hydroponic gardeners in Denmark were the first to discover its advantages when used as a growing medium. Nowadays, rockwool is highly valued and commercially available in the forms of rockwool cubes and rockwool plugs. To produce rockwool stone and sand are melted together and then spun into various shapes and sizes, which sounds similar to the production of cotton candy.

Rockwool Advantages

Rockwool cubes (sized 36” by 12” by 3”) are very convenient to use, because they can be easily cut to a shape matching your needs. This material perfectly holds water and air, being very porous. Therefore, the roots of the plants will be protected both from rotting and drying out in case of the pump malfunction or other event long enough for you to be able to correct the situation.

The granules of the rockwool plugs keep together well and are not less easy to use.

Precautions

Unfortunately, rockwool has weakpoints as well, besides the benefits mentioned above. It can hardly be called environmentally friendly, as it is made of rock and thus does not bio-degrade, requiring some efforts to eliminate it. Moreover, it can be dangerous for the human health, causing silicosis if accidentally inhaled. For this reason, it is recommended to wear a face mask with a HEPA filter and handle rockwool carefully. 

One more thing, a gardener should keep in mind while using rockwool, is that this material has a very high pH level, which should be reduced with available acidic substances and regularly checked.

In spite of the rockwool cons, it is still so easy and comfortable to use that it remains the most popular growing medium type among the hydroponics gardeners. The only thing to do is to take necessary precautions while working with it.