Chapter Two Hydroponic Grow Media – Who Needs Soil


If you are being 100% hydroponic you will be growing in the absence of soil.  In other words, something that is completely inert.  It is not the hydroponic grow media that feeds your plants.  The only real purpose of the media is to anchor the roots in place and provide plant support.   Nutrients are added to the water for the system.   Want to know more about Nutrients, check out our post entitled “What Are Your Plants Eating?  and “Essential Plant Nutrients for Your Hydroponic Systems.”

There are a number of inert growing media available for hydroponic growers;

 The Most Commonly Used:



Clay Pebbles – are a growing medium that is most often used in hydroponic gardening. … While clay pebbles do not offer their own nutrients to plants, nutrients and water can be easily added for healthy growing cycles.




Coco Coir – is a spongy, soilless growing medium that may be added to soil or potting media to increase moisture retention, drainage, and aeration. 100% organically derived from coconuts.





Rockwool – is made by melting basaltic rock and spinning this molten mix into thin fibers which are then cooled by a stream of air.  Rockwool is a popular growing substrate for hydroponic gardening and is perfect for seed starting, ebb and flow systems, and drip irrigation hydroponic systems.  Care should be taken if handling in large bulking quantities, masks are recommended in that case.


Oasis Cubes


Oasis Cubes – are a commercially available solution for starting cuttings and seeds, and for growing plants in an indoor setting. They are made of foam and are completely inert, which means they have no impact on pH.  They are probably the simplest way to grow hydroponically and support the roots very well.  Aeration provided through the foam is second to none of that of any other hydroponic growing medium.




Perlite – a volcanic glass that is mined and then heated in big ovens until it ‘pops’ into a round, white material that’s used in seed-starting and potting mixtures to lighten the soil, allow more air around the roots of plants.





Vermiculite – Is a of hydrated laminar minerals (aluminum-iron magnesium silicates) which look like mica. Horticultural vermiculite is processed with massive heat that expands it into accordion shaped pellets composed of multiple layers of thin plates. Vermiculite will not rot, deteriorate, or mold and is enduring, odorless, non-toxic, and sterile.



Perlite and vermiculite media are used to complement each other  – perlite drains fast whereas vermiculite holds moisture. They are often mixed in a 50/50 formula, which keeps the mix from being washed away in ebb and flow systems. It can be used in the drip system, aeroponic system.   Check out other Chapters in our A Complete Guide to Hydroponic Growing.

We invite you to visit our other posts and to check out other chapters of this guide as they become available.   Have a question, or just want to say hi – drop us a comment below.

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