Definition - What does Rockwool Cube mean?
Rockwool cubes, also called stonewool cubes, are best used to germinate seeds and root cuttings. They are a form of rockwool, a popular growing medium for hydroponic gardening.
Manufacturers create rockwool cubes by spinning a combination of basalt and chalk to create an intertwined mixture that resembles the consistency of cotton candy. The material is them pressed and formed into cubes. Most rockwool cubes measure one to two inches and come in their own wrappers that are best left on throughout the growing process. Larger rockwool cubes can also be purchased that measure three to four inches.
Large rockwool sheets are also available that may be cut to fit a custom sized planter or system.
MaximumYield explains Rockwool Cube
Rockwool cubes naturally have a high pH level of around 8. The high pH is caused from the lime used in the manufacture of the cubes. Prior to using rockwool, most growers will soak the cubes in a pH adjusted water. A pH of 5.5 and 6.5 is ideal. If the water’s pH is above 8, it can harm the rockwool.
After the rockwool cube’s pH has been adjusted, it is time to soak the cube in a water-soluble nutrient mixture. A seed can then be placed into the small hole in the middle of the rockwool cube. The seed can be placed just slightly below the surface layer of the rockwool. Seeds that are grown in rockwool typically germinate fastest in a room temperature of 70 to 80 degrees Fahrenheit. Place the rockwool cube in a well-lit area or beneath a grow light.
Depending on their size, rockwool cubes are intended for small plants; however, many growers simply transplant seedlings from small cubes into larger cubes. Otherwise, the rockwool cubes can be transplanted directly into the soil or used in a hydroponic set-up.
In addition to rockwool cubes, there are also rockwool slabs available on the market in multiple sizes. Rockwool cubes, in addition to slabs, are lightweight and can be reused, making them a popular choice in commercial operations.
Rockwool cubes have the added convenience of being portable, unlike the slabs.