| The most widely-spread growing medium is, perhaps, | | | | whether it is a small 1" cube for seeds propagation or |
| rockwool. Originally used for insulation purposes and | | | | a large 3x12x36 inches slab for huge plant, rockwool |
| also known as mineral insulation, rockwool was first | | | | offers a wide variety of shapes and sizes to choose |
| used as growing medium by Dane gardeners. Now, it | | | | from. Besides, loose rockwool is also available, |
| is frequently used for drip-style indoor gardens | | | | designed for filling different plant containers. |
| around the globe. | | | | NO DUST AND EASY TO USE – since rockwool |
| Rockwool is produced by a process similar to making | | | | maintains its form almost perfectly, it cannot be |
| cotton candy: a particular mixture of sand and rock is | | | | scattered accidentally. Besides, usually packed into |
| melted and then turned into fibers by spinning the | | | | plastic rockwool is a very clean material that is easy |
| mixture to form products of multiple shapes and | | | | and comfortable to work with. |
| dimensions, from 1" starter cubes and up to large | | | | Rockwool’s Weak Points |
| slabs of 3"x12"x36" in size. The variety of available | | | | NOT A “GREEN” MATERIAL - rockwool is |
| forms and sizes turns rockwool into one of the most | | | | claimed to be not environment-friendly material, |
| widely-used growing mediums. | | | | because of its almost indefinite time of breakdown. |
| Key advantages, as well as disadvantages, of this | | | | HEALTH HAZARDS – rockwool particles and |
| popular growing medium are listed below. | | | | fibers pose serious health danger, especially for |
| Rockwool’s Strong Points | | | | human lungs. That is why it is necessary to wear a |
| HOLDING WATeR – rockwool as a growing | | | | protective dust mask, while working with rockwoll.pH |
| medium in hydroponics systems is capable of holding | | | | PROBLEMS – because of rockwool’s high pH |
| a large amount of water. This creates an additional | | | | level, it is necessary to balance pH level in the |
| protection for situations, when water is not supplied | | | | nutrient solution properly and make it suitable for the |
| because of power outages or failures in pumping or | | | | plants, you are growing. In general, the use of |
| other gardening equipment. | | | | rockwool requires more routine work to keep pH |
| ACCUMULATING AIR – up to 18 % of air are | | | | level of your nutrient solution at steady level. |
| constantly kept by rockwool. Due to this capability, | | | | LONG PRE-SOAK PERIOD – before rockwool can |
| there is a very little risk to over water rockwool; | | | | be used in the hydroponic system, it should be |
| besides, the plants are always supplied with enough | | | | soaked for at least 24 hours beforehand. Other |
| amount of oxygen. | | | | growing media usually do not require pre-soaking, it is |
| MULTIPLE SHAPES AND SIZES AVAILABLE – | | | | enough just to well-water them. |