Inert Grow Medium

Definition - What does Inert Grow Medium mean?

An inert grow medium is a type of grow media that contains no nutrients.

In general, a good grow medium ensures that plant roots have a place to anchor and retains moisture at the same time. Some types of grow medium, such as potting mixes and soil, come pre-charged with nutrients and amendments in many cases. These would be considered the opposite of an inert medium.

Growing using an inert grow medium is an important consideration for both hydroponic systems and aquaponics systems.

MaximumYield explains Inert Grow Medium

In hydroponic and aquaponics systems, plants are grown without soil. However, plants still need something in which to anchor their roots, and something to support them during growth. An inert grow medium is used for this purpose, as well as to retain moisture to help foster healthier plants.

There are quite a few different options available when it comes to choosing an inert grow medium. One of the most popular is rockwool. This is made from actual stone, which is melted and then spun into fibers, similar to steel wool. However, rockwool is not 100% biodegradable, so it may not be the right option for you.

Another popular choice is LECA, or lightweight expanded clay aggregate. Generally found in the form of pebbles, these are made from 100% organic clay. They do not biodegrade, and can provide a permanent grow medium for your plants. LECA pebbles contain tiny capillaries that retain moisture very well for long periods of time.

Coir, or coco fiber is another popular solution. While it is organic in nature (it’s made from coconut husks), it is inert in that it does not contain any harmful microbes, nor does it supply plants with any nutrients. However, it does break down over time, and it naturally resists mold and fungus.

Perlite is another inter grow medium that many growers turn to, particularly for starting from seeds or new cuttings. Perlite pebbles are very small, and are chemically inert. However, they may float if flooded, and are not ideal for mature plants.

You’ll find numerous other options available, as well, including vermiculite, sand, gravel, and more.

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