Rock-wool can hold large quantities of water and air that aids root growth and nutrient uptake in hydroponics; the fibrous nature also provides a good mechanical structure to hold the plant stable.
Rock-wool is made by melting a combination of rock and sand and then spinning the mixture to make fibers which are formed into different shapes and sizes.It is used primarily for drip hydroponic systems.
Rock-wool Cubes have a pH of roughly 7.8. This is pretty alkaline, yet our plants prefer to grow in a slightly more acidic environment (between 5.5 – 6.5).
In order to prepare our Rock-wool cubes for the seeds, we need to soak them in some pH adjusted water, that way they have everything the seeds need to germinate and sprout.
Please note: A water PH lower than 5 will damage the fibers of the Rock-wool cube
Do not Squeeze them to drain any water: Rock-wool Cubes are designed to maintain the correct water to air ratio and squeezing them may damage their structure.