Grodan Rockwool Blocks come in either 3 or 4 inch square versions, with either small or large holes. The smaller size hole is used to transplant the 25mm Rockwool Propagation Cubes and the large size hole is used for the 36mm Rockwool Propagation Cubes, Jiffys and Root Riots. The size of block you need sometimes does not necessarily make a significant difference, but there are of course more suitable applications than others depending on the system that you are using. Please feel free to give us a call to see what would be most appropriate for you.

Using rockwool as a hydroponic substrate gives you fantastic advantages over traditional growing media for your indoor garden. Firstly, the water holding capacity is much greater, meaning litre for litre it can hold substantially more water than coco coir or soil. It also releases this water much easier than soil or coco does, meaning the plant does not use as much energy obtaining the water from the substrate. This means you can use a lot smaller volume of media, and your plant has more energy available for vegetative or generative growth above ground. Maximum efficiency in almost every way!