Rockwool, AKA Stonewool, is a horticultural stonewool that originated in Denmark around 1969. Since then, its popularity has exploded all over the world with both hydroponic gardeners and conventional soil gardeners. It is made of molten rock that is spun into cotton candy-like fibers. Then, it is shaped into conveniently sized cubes.
Rockwool is great for starting seeds and propagation of plant by rooting cuttings. Then, the plant with the cube can be planted directly in the garden or used in hydroponic systems.
It is really nice to use when starting seeds, too! The rockwool 1.5 inch cubes come in a slab that fits perfectly into a growing tray. The cubes have a small hole on top of them, where a seed can be planted. After the seeds germinate, the cubes can be easily broken apart and each rockwool cube will fit perfectly into a 2 Inch net pot!
The pre-made planting hole in the cubes also works great for rooting cuttings, too. Once the roots on your cuttings develop, all you need to do is separate the cubes and transplant your cuttings using whatever method of gardening desire.
Rockwool is naturally mold and fire resistant. It is made from inorganic molten minerals. There are no nutrients in this medium, so after your seeds start, be sure to feed them with the hydroponic nutrients of your choice. It is important to keep the cubes moist to supply water to your plants as they grow.
When planting in these cubes, the directions say to use a little lemon juice when initially soaking the cubes in water. This is because the cubes are slightly alkaline. I have never done that and I get excellent results. All I do is soak the cubes in a mild solution of water and nutrients and my seeds seem to sprout and thrive very quickly. In fact, I have better results starting seeds it rockwool cubes than any other medium, when doing it this way. I think that they work much better than Peat Pellets or Coco Coir.
These cubes come in several sizes and they are very easy to work with. I think that they are so much more pleasant to work with than many of the other options. In fact, I have used these cubes to start plants to later plant in my conventional soil garden, even though they are designed to be used in just about any hydroponic system.
Another way that I have used them is to put them into a Kratky Hydroponic System and place Tomato Suckers into them. Each tomato sucker will easily root and become a new plant. It is then up to you to transplant them into another Hydroponic System, like a Deep Water Culture Hydroponic System, or transplant them into the ground.
So, pick yourself up some of these premium rockwool products and start planting your dream hydroponic garden today! You will be delighted with the ease of use and success these wonderful cubes will manifest in your garden.