Dangers Of Growing Marijuana On Rockwool

Cannabis dangers growing rockwoolWhat dangers come along with growing marijuana on rockwool? It doesn’t seem to bother me when I handle it, and I don’t take any safety precautions. Is this prudent?

When growing marijuana on rockwool you have to be carefull because handling rockwool fiber actually does damage the skin and lungs in some instances. When it is handled, the almost microscopic pieces of fiber puncture and lodge in the skin. You may notice small swellings and itching where the fiber has entered. Strands that are highly alkaline should eventually dissolve in the body’s acid environment. Dry rockwool fiber creates a dust full of tiny, short pieces of fiber, some of which are microscopic.

Rockwool flocking, which is stuffed into containers, is considerably more likely to lose strands than the cubes or slabs are. It’s easy to breathe in these dust particles which then stick to the small air passages in the lungs, producing small, transient ulcers or sores. The body’s acid environment interacts with the alkaline rockwool to help dissolve it. There are three vital precautions you should take when handling this material:

  1. Cover your entire body when working with rockwool. Be sure to wear gloves, long pants, a long-sleeved shirt, shoes, hat, face mask (a paper bag will work), goggles, and a high-quality dust respirator. Wearing disposable paper painter’s overalls is the best option.

  2. Prior to handling, moisten the rockwool so it doesn’t produce as much dust. Wet fibers won’t break as easily while making them less likely to become airborne if they do happen to break apart.

  3. Ensure that you have good ventilation or are just working outdoors.

Canna, grodan and many other brands have rockwool wrapped in plastic with a little hole in them to plant the marijuana clones. These rockwool slabs are perfect for growing marijuana and I definitely would advise to use them.


Not a big fan of Rockwool. I use Oasis cells. they feel a little like a Styrofoam and are easy for plants to root in. From there you can transplant directly into soil or a hydroponic system. The cells are about 1 inch square at the top and tapper down at the bottom. they don’t hold a bunch of water so they require a little more attention than Rockwool, but the up side in my opinion is you have less of a worry of root rot. Great for cloning with a misting table.