Aquaponics - Selecting the Right Grow Media

As always, I encourage all to methodically think out their system before getting started.  I have seen too many mistakes made because of poor planning.  Yes, there is an excitement of getting started, but a poor consideration of your system can lead to failure, extra time, and wasted money.

If you go the route of using grow beds with media, please consider all options before making a choice.  Your location and the availability can affect your consideration and I understand; like in my case living in Honduras.

​Some may ask, what is the purpose of grow media?  It serves many purposes and some are obvious; it gives support to your plants and their root system.  BUT did you realize, that in order for your system to be successful, you have to have a friendly environment for your bacteria colony to grow?  The grow media provides an area for bacteria to develop.  It’s known as, Biological Surface Area.  Also, grow media serves as an exchange for oxygen and moisture, and gives worms a comfortable habitat to live in.

​Isn’t all grow media the same?  Doesn’t it all do the same thing but made of different material?  Why is it so important?  No, they are not all the same.  As mentioned above, biological surface area can radically change from one type of media to another.  Is it pH friendly?  Is it the right size?  These are some considerations and questions I had when getting started with aquaponics.  Fortunately, I did careful research and made the right choice right away.  I hope this article will help get you in the right direction.

Here are some keys things to take note of when selecting your media.

Inert – As mentioned already, all media must be pH neutral.

Size – To small or to big can affect the performance in your grow beds.  To small can cause compaction or clogging, especially if any fish waste makes it way into the grow beds.  To large can cause air gaps and can cause a negative effect the growth of the plants.  Your media should be around 1/2” to 3/4” in size.  This will help prevent compaction and any air gaps all the while, providing an excellent biological surface area for bacteria growth.

Weight – The consideration here is lightweight more so.  You don‘t want your media floating.  When floating, it will have the propensity of clogging up your system.  Also, to heavy, it will become cumbersome to handle.

, Depth – Allow around 10“ to 12” of grow media in your aquaponics grow bed.

Easy on the Hands – remember not only do you need to use your hands to move the media around, your plant root system must have something gentle as well.  Your grow media can‘t be to sharp that you are injuring yourself and damaging your roots.  You want it to be smooth enough, but porous enough to encourage bacteria growth.

No Decomposition – Obviously, you don‘t want anything that can decompose!

Avoid Limestone – As mentioned in the previous article, make sure your media is neutral and it will not affect your pH in the system.  I have seen people go to their local lawn and garden store and buy landscape rocks to use in their system.  What is the harm they may think, it’s just gravel?  Well, that gravel may contain limestone and it’s not pH friendly.  It will play havoc with your system.  It’s extremely important that you test any gravel or natural product you use in your system.  Here is a video, You Must Test Your Grow Media, I produced to show you a simple test that can be done in your home.  I always say, TEST, TEST, and more TEST!  You can never be too cautious.

Rinse before Using – Be sure to thoroughly rinse any dust and debris from your aquaponics grow media before using it in your system.

pH Management – Just because your aquaponics grow media is pH-neutral doesn’t mean your system won’t become too alkaline or acidic. The optimal range for most aquaponic systems is a pH of 6.5-7.0. Monitor your pH closely and adjust accordingly.

Coco Coir – As is the case with most organic grow media, coco coir tends to break down in aquaponics systems. It also holds too much moisture, discolors the water, and may even cause your pH to go out of whack. Coco may work just fine as a top layer, but we don’t recommend filling your entire grow bed with this media.

There you have it, your first introduction to grow media.  The next articles, we will be covering the media in itself in a greater depth.  I certainly hope you enough these blog post.  Please share them on your social media.  Feel free to comment as well.  Let us know what about your failures and successes, together, we can make aquaponics a brighter future!

Check out our website:  www.MorningStarAquaponics.com