Choosing The Right Medium For Your Hydroponic System

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In hydroponics, a “growing medium” is what you will use instead of soil.

One of the biggest advantages of a Hydroponics grow system is foregoing the use of soil in replacement of soil-less media. This means you won’t be affected by the various soil-borne bacterial, viral, and fungal infections. Plants in a hydroponic system still need a grow medium to embed their roots and offer support for the growth of the plant. The medium should offer a good degree of moisture absorption and drainage capabilities, have good aeration properties, and has an excellent Cation Exchange Capacity.

When developing your hydroponic system, it is imperative that you select a medium that matches your needs, will give you the biggest yields, and will be the easiest to maintain. Here are a few of the most popular growing media used in modern hydroponic systems, and the advantages and disadvantages of each.

Coconut fiber, sometimes called cocopeat, is simply the powdered husks of coconuts. It is increasing in popularity because it is one of the completely organic media available for hydroponic systems. It is known for its large oxygen and water capacity, which means your plants have a better chance of surviving if something goes wrong with your hydroponic system.


Arguably one of the most popular media to use are Hydroton Expanded Clay Pebbles. These are made by expanding clay to form round balls of porous material. The best part about them is the fact that they release almost no nutrients into the water stream and are pH neutral. In addition, their spherical shape and porousness help to ensure a good oxygen/water balance so as not to overly dry or drown the roots, which is a big problem with rockwool. Hydroton can be used in all sizes of net pots for any kind of NFT, DWC, or Dutch Bucket system.

Perlite makes a great hydroponic planting medium due to its light weight, porosity, and inert nature. Perlite is made by heating silica (flakes of glass) until it expands (like popcorn). This medium keeps plants more open to air, while still having good water-retention properties, and therefore it makes a good medium for hydroponics.  It is often used as a filler and mixed with heavier media to help improve drainage.


Rockwool is probably the most popular growing medium used in modern hydroponic systems. It is a material made from basalt rock and which, which is melted and “spun” so the material turns into interconnected fibers. One of the primary advantages of rockwool is that it retains water very well, which means that your plants are less likely to be harmed by dehydration if your pump fails. It also holds a great deal of air, which means that it will make it more unlikely for your plants to be over watered. However, the dust and fibers from this growing medium can be hazardous, so you have to careful when you handle it. Because this material has a high pH level, you may need to pay special attention to the pH level of your nutrient solution to ensure the plants in your hydroponic system remain healthy.


Floral foam can be used as a growing media in hydroponics as well, and is similar to the oasis cubes, though the cell size is larger in the floral foam. They are rigid green used by florists to hold the stems in their flower displays. Floral foam is an open cell material which means that the cells can absorb water and air. The open cells wick moisture throughout the material, and the roots can easily grow and expand through the open cell structure. While similar to rockwool, floral foam doesn’t become waterlogged as easily as rockwool cubes. Even so don’t let it stay in constant contact with the water supply, or you’ll still have water logging issues.