Rockwool

Rockwool is made from the spun fibres of superheated volcanic rock. It is then manufactured into blocks, slabs, cubes or sold loose as floc. Not used extensively in Australia as a grow medium, it is however used extensively in Europe. Most of our customers use rockwool for propagation, as it is easy to transplant the new plants around, into grow systems, etc.

Rockwool is not pH stable so it is a good idea to soak it in a pH modified solution of about pH 5.5 before use to lower it's naturally high pH. It is also a good idea to wear gloves or try not to handle it too much because it has the texture of fibreglass and can irritate the skin. Floc is best kept damp as the fibres are quite loose and can become airbourne, irritating the lungs if inhaled.

Growing in rockwool is not favoured in Australia because of its high water holding capability. Think of it as a sponge. You have to be careful with your watering otherwise your roots will develop rot from sitting in a damp environment for too long. Dripper systems are best suited to this type of medium.

Rockwool can be reused but it needs to be sterilised first - use a product like Oxy Plus or HydroClear and soak for a day or more if you have the time. The Hydrogen Peroxide in the product will break down in water in this time so the rockwool will then be safe and sterile to use again.

Suitability of use

Dripper systems

The Hydroponic Warehouse
Shop 3, 73 Pickering Street, Enoggera
Brisbane QLD Australia
(Opposite Enoggera Bowls Club.)
Phone: +61 (07) 3354 1588 Fax: +61 (07) 3354 3622