The Urban Green 12 pack of rock wool cubes are perfect for propagation and a great growing medium that maintains perfect aeration and moisture levels at all stages of plant growth.
 
Rockwool cubes might be the most popular hydroponic growing medium. It’s so popular because it takes up minimal space, provides some incredible plant growth and doesn’t cost a lot of money. 
 
Rockwool cubes come completely dry, so it is crucial to soak them prior to use.
Set your cubes in a tray that has some of your nutrient-rich solution in it. You an also just use regular water for this part if you want, but we suggest using the nutrient solution if you can. The cubes can be totally submerged or partially. This doesn’t take long and you’ll know your done because bubbles will stop rising.
 
Simple and easy to use, just plant your seedlings and add water.