Rockwool

Rockwool Insulation

While it was originally used as insulation under the name "Mineral Insulation" it became developed for the drip style hydroponic system. It is made my melting a combination of sand and rock and then spinning the mixture to make fibers formed into different shapes and sizes. The process is similar to that of making cotton candy. Rockwool has many advantages to it. It is free of disease, and it supplies water and nutrients to the plants while balancing the air and water. Rockwool is steerable meaning that it gives the plants exactly what they need throughout the cultivation process. The steerabily of rockwool provides and improved crop and will save the grower about 10% in water and fertiziler needed to reach the same results using other hydroponic mediums. There is also consistent water content and density. This provides a "buffer" time against power outages and pump or timer failure. Because of the variety of shapes and sizes, it is suitable for all different types of plants and all pots and containers yet it holds together so that it remains a clean and convenient form of gardening. It also comes wrapped in plastic which makes it easy to handle and keeps evaporation to a minimum.

Rockwool Cubes

Although unused greenhouse soil may have many of the same advantages associated with Rockwool, greenhouses are also somewhat inconsistent in water content. Wet and dry patches are often found. The soil may also be contaminated with diseases.

Despite all the advantages to Rockwool, there are several disadvantages as well. For one, it is not environmentally friendly. It is hard to dispose of and if buried it will last forever. Also, the dust and fibers are bad for your lungs. It is recommended that one wears a dusk mask when handling Rockwool to prevent breathing problems. Rockwool also has a high pH meaning the nutrient solution will need to be adjusted and more routine maintenance will be needed to keep pH levels correct. Lastly, rockwool must be soaked for 24 hours before using while other mediums often only need to be watered.

One type of rockwool is rockwool cubes. For 3" and 4" cubes, they can be the primary growing medium or in conjunction with others. For small plants one large cube may be all that is needed. Smaller cubes are used for cuttings.

Rockwool Slabs

Another type of rockwool is rockwool slabs. They come in 6, 8, 10, and 12 inch widths. They are all 3 inches deep and 36 inches long. Many people start their plants in rockwool cubes and then transplant them to the slab.