What is the best growing media for aquaponics?

The best grow media for aquaponics is comprised of specific factors that help it perform its intended functions. By knowing these factors, you can make empowered decisions in choosing which grow media fit your aquaponics garden. This article will serve as a guide for you to determine the qualities you should look for as well as the available grow media in the market today.

What is a growing media?

When it comes to farming without the use of the natural soil, the growing media is without a doubt one of the most critical components. Although grow media are not used in all forms of aquaponic farming, such as the floating raft system, they are still considered to be an integral aspect of the media-based approach in aquaponics.

The body of your plants is supported by aquaponics grow media, which is a natural or synthetic soilless material. Additionally, it offers protection to the developing root system of your aquaponics crops.

How important is the growing media in aquaponics?

Aquaponics grow media have two significant purposes. I briefly discussed each below:

It keeps the roots in.

A strong root structure is required for a plant to grow and establish itself. This helps it receive the nutrients it needs while also keeping it in proper positioning. Strong roots keep plants from falling over or being uprooted in adverse weather.

Aside from that, all of the nourishment supplied externally by farmers is absorbed by the roots. Thus it is critical always to protect the roots' safety.

Through the aquaponics grow media, you are assisting the roots in performing all of their intended roles to keep your crops healthy and thriving. Keeping the roots' in the proper position, as well as improving their stability, is another excellent reason why growing media is a must. It also serves as a source of nourishment, allowing the roots to absorb all of the vital nutrients that the farmers have placed in the medium.

It provides bacteria with their needed surface area.

To sustain the plants in your aquaponics garden, aquaponics heavily relies on the bacteria that naturally form within this ecosystem. The bacteria are essential in this process since they aid in converting fish waste to nitrites, which are then converted to nitrates, which the plant eventually absorbs.

However, the bacteria need a surface to cling to as they try to develop in the aquaponics system for the nitrifying process to occur. In fact, the greater the surface area, the greater the number of bacteria that can develop internally, resulting in better ammonia conversion. This is where the growing media comes in.

Good aquaponics bacteria dwell on your growing media, where they perform they break down the excrements of your fish, turning them into usable nutrients. You can achieve a vast surface area using tiny amounts of larger grow medium or larger quantities of smaller grow media. That is why you must be aware of the many sorts that may suit your system.

What are the requirements for an excellent grow media?


This quality describes the growing media as pH neutral. Remember that controlling the pH level in your system is critical; it's something you'll have to perform daily. For this reason, your grow media should be able to adjust to the pH your fish and plants will require.


Grow media for aquaponics should not be too heavy that it becomes unmanageable, nor should it be too light to float around and clog up your system. It's best to use light to medium-weight material.


Your aquaponic media bed should have a depth of roughly 31cm (12 inches). This is a sufficient depth for the growing media to perform its functions, such as sustaining the roots and providing the bacteria with a suitable habitat to grow in.


Here is another vital factor to consider in choosing your aquaponics growing media. Your system may become clogged if you use too small grow media. When the media is excessively big, it can generate air gaps, which can stifle plant growth. I recommend using aquaponics grow media of 12" to 34" in size, with enough surface area for bacteria to colonize.

Easy on the hands

For some obvious reasons, you will need to use your hands in handling the growing media of your choice. This is very true when it comes to placing it in your grow bed. Since this is the case, it implies you want something that is easy on your hands and that you enjoy working with. Lava rocks, for example, are porous and have a vast surface area. They are, however, razor-sharp and can cut your hands.


It's crucial to make sure your aquaponics grow media will not break down or degrade in your system. This situation reduces the surface area available for bacteria, leading to clogs or anaerobic pockets in your grow media. The latter can be very harmful to your plants.


It would be best if you would also think about the price of the growing media you will use. Depending on the sort of aquaponics grow material you want to use, it can vary significantly. Hydroton is a costly example, but gravel is usually the cheapest. If you are just beginning your aquaponics journey, it is critical to suit your budget with expected outcomes.

What are the different types of growing media?


One of the most commonly used hydroponics growing materials is Rockwool. This media comprises granite and limestone and is non-degradable, porous, and sterile. It's made by melting and spinning rock into highly long, thin threads that look like fiberglass. They make slabs, blocks, cubes, sheets, or flocking out of these fibers.


This next grow media is a silicate mineral that expands at extremely high temperatures, similar to perlite. It does, however, have a larger cation-exchange capacity, which allows it to store nutrients for later use. Because of its small weight, vermiculite tends to float. There are many various varieties of vermiculite on the market; you may buy it at a nursery or order it online, but make sure it's for gardening purposes.


These are made from repurposed glass. Growstones resemble grow rocks (Hydrotron) in that they are lightweight, reusable, and porous; however, they are unevenly formed.

One notable feature of growstones is keeping the root zone moist and aerating it well. Due to their high wicking abilities may retain water up to 3-4 inches above the grow media. As a result, good drainage or depth is required to ensure that the water does not wick all the way to the top. If the growing medium's surface is constantly damp, it might produce stem rot.

Even though growstones are made of recycled glass, the pieces are not sharp to cut you if they break.

Pine shavings

Organic and affordable pine shavings are also another option for aquaponics grow media. These are commonly utilized in commercial aquaponics systems. Pine shavings are frequently confused with sawdust, which compacts and readily clogs the water. For this reason, you have to exercise extreme caution.

Also, ensure that your pine shavings are made from kiln-dried wood and are free from chemical additives. All hazardous materials, including wood sap, are burned away in the kiln.


Lightweight Expanded Clay Aggregate (LECA) is a highly effective growth medium made from clay balls that have been processed at a super-high temperature. It is, without a doubt, one of the most widely utilized media in hydroponics and aquaponics due to its versatility.

Clay pebbles are light yet hefty enough to give a plant sufficient support. They are even pH-neutral, non-degradable, and do not add a lot of nutrients to the water. Their porous substance and spherical form help maintain a healthy oxygen-to-water ratio while also offering a smooth working surface for gardeners.

River rock

River rock is often spherical, having been sculpted by the river's flow over it. It is best to go with a medium grade; anything smaller will likely jam up the grow beds. Of course, if you decide to go for bigger pebbles, you will not have the required surface area. This type is one of the more affordable solutions, and it should be available at your local shop.

River rocks are an excellent medium for anyone new to aquaponics but keep in mind that it has some weight issues, so make sure your grow bed can handle it.

How can I improve my growing media?

There are many ways to assist your growing media in performing its intended functions:

Use worms

These gardening creatures are helpful in dealing with the solid breakdown of your growing bed. The solids are food for the worms, and as they process these, they will excrete the minerals which your aquaponics crops will use.
If you want to find out more about everything around worms in aquaponics you should check out our post: "Is it good to have worms in aquaponics?"

Clean the grow media

To avoid clogging your grow bed, it is recommended to clean the grow material once a year to eliminate particles and other unwanted materials. Anaerobic zones can form in a congested grow bed, killing the beneficial bacteria. A clogged grow bed will also slow down the nitrification process and cause your pH to rise. A high pH level could indicate that your grow bed is blocked.

Observe proper depth

The depth of your grow material should be 12 inches. You should, however, add an extra two inches on top of that. Algae or fungus development will be considerably reduced as a result of this. A good example is 12 inches of flooded and drained wet media and 2 inches of dry media that inhibits sunlight from reaching the wet grow media.


The grow media has an important role in keeping your aquaponics crops healthy which eventually leads to a profitable harvest. Knowing the different factors that make an excellent grow media will help you decide which fits your situation and budget. The information I shared in this article should help you make an informed decision as you select what growing media will end up in your garden.

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