Remember your first grow? Maybe it was in your back yard, the garage or even basement! Many of us just used soil from the local garden store or even tried a small PVC hydro setup! While both grow methods are still used today, they are often used by armature growers. For those who are growing for a living, there are two other common growing mediums. These mediums are called rock wool (RW) and coconut coir (CC). There is a well-documented debate between which offers the plant a better home for their roots. Let’s take a brief look at both options and determine which may be better for you.

First off let’s discuss RW. RW is a man-made product created from basaltic rock (silica). It resembles building insulation and shares many of the same properties. The process in which the basaltic rock is turned into RW uses a great deal of heat and fortunately creates a sterile product. RW provides a perfect medium for growing in hydroponic systems or simply on a table tray. RW is known for its incredibly fast dry down times allowing for the grower to water/feed more often without the fear of over feeding a plant. If for some reason the RW has not “dried”  it can be flushed, removing lingering nutrients that hasn’t been absorbed by the plant.

Now the downside, the creation of RW requires a great deal of energy to produce and is more expensive than CC. RW It is potentially irritating to humans. In fact, The United States Environmental Protection Agency lists it as a “Group 2B” product and “potentially carcinogenic to humans”. Lastly, being a man mad product it is not able to support the microorganism’s that a natural medium can.

CC has its pros and cons just like RW.

First CC is natural and can host microorganisms that RW cannot. CC is made from coconut husks and has a pH that is naturally neutral. CC can release nutrients efficiently because of its 5.9 to 6.4 relatively neutral pH. Having nutrients released readily to plant roots will help your plants grow quickly. It is also much more affordable than RW. CC can be used in both hydro and tray set ups.

The downside largely revolves around CCs high salt content, especially in lower grades. Coir high in salts should be leached before use. It is also inert, it doesn’t have much or any nutrients to provide the plats. So, like RW you will have to add in all nutrients needed by the plants.

In summary, both RW and CC can provide many crops the perfect home for their roots. It all depends on what your growing, the money you have and your previous growing experiences. Our view is to always try something new, set up a small test environment and see what you can produce.


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