Rockwool. I immediately envision those pet rocks of the 70s standing around, sheep-like, grazing in green pastures, when someone comes along with shears, cutting off their coats, creating Rockwool. It's actually made from basalt and various other rocks or rock by-products. It is heated and woven into long strands. I had never heard the word "basalt" used as much as it has been since I've moved to Washington. It is used like a trophy around these parts and it is everywhere. It comes from lava flows, so that should tell you a lot about our little corner of the world.
Again, my imagination takes over. In my mind, I picture how cotton candy is made. Sugar heated, the strands form a delicious cottony delight that melts in your mouth, except Rockwool is definitely not edible. Depending on how Rockwool or mineral wool is made, it can be considered eco-friendly, with up to 45% recyclables used. However, once you buy some, plan on it sticking around for a long time (forever). It is suggested that you clean and sanitize it, and reuse it over and over again.
Much of the Rockwool made is used for insulation, which can also be used for your starts in hydroponics. This means you would have to cut and drill your own cubes. I opted for the more expensive precut Rockwool cubes with the holes for seeds already drilled since I am starting small. Mine came with plastic gloves. It is recommended that you wear goggles, protective clothing, gloves, and a dust mask when working with it, as a safety precaution. I haven't opened my package yet. I will wait until I am ready to soak them.
The next step will be preparing a tray. I should be able to get 28 plants started, so I will eventually need some more food-grade buckets. The label on my Rockwool says to soak it in a plant food solution, keeping the ph at 5.5 by using something called "PH Down", or a lemon.
Most of the information I have found states that a PH meter is the most important tool for hydroponics. So that is what I will be shopping for next.