Please read my previous post regarding grow media (click here). It was an introduction to this subject. It will shed light on grow media and the characteristics of what you should look for when choosing a media. As I stated before, what you choose will be dictated by what is readily available to you in your local area. I live in Honduras and the only media available at the time of building my system was river rock or gravel. A long as you properly test it before use, it is a good product to use.
Here are the top 5 grow mediums in use in aquaponics system. I am not saying these are the only ones, but these are the main ones in use at the time of this writing. You can look into other products, but I would highly recommend using my previous blog post on grow media as a guide. The least thing you want to do is experiment with a new product and have to remove it because it didn‘t work in your system.
The list you see here is provided by uPonics.com
Their highly-porous composition and spherical shape help to maintain a beneficial oxygen to water balance while also providing gardeners a smooth surface to work with (ie, they won’t cut your hands!).
A possible downside is the initial expense of purchasing bags of LECA. However, since this grow media is totally reusable, in the long run, clay pebbles are an investment that will serve you over the course of many grows and many years. Because clay pebbles have very few drawbacks and fit every criterion for a great aquaponics grow media, they are our top pick.
Expanded shale has a slightly polished surface area, so – like clay pebbles – it’s easy on the hands and will not harm the root system of your plants. Additionally, shale is reusable and typically manufactured in the USA. For all of the positive characteristics of expanded shale, we rate it as #2 on our list of best aquaponics grow media.
So while they are reusable, they should be thoroughly cleaned between grows to remove any plant debris. Additionally, there is some debate over whether growstones alter pH in an aquaponics system and whether they can break down over time. We would advise you to soak your growstones for a few days before using them and test the pH until it consistently reads neutral. And if you are concerned that growstones may break down over time, just opt for LECA or expanded shale. For the aquaponics gardeners, growstones provide a problem-free aquaponics grow medium.
That aside, lava rocks have numerous beneficial aquaponics grow media properties and might be worth a shot if you don’t want to use LECA or expanded shale.
as limestone is often present. If you must use gravel, look for stones that have been polished down to smooth out its rough texture.
I hope this list will give you some direction in the pursuit of aquaponics. There are plenty of choices available. Obviously, there are better choices over others. But, it comes down to what is available and fitting within your budget.
Make sure you stay tune to our blog, we will have many other postings coming soon. Also, check out our website, www.MorningStarAquaponics.com
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
Getting these in harmony is key. The ideal neutral level is a pH range between 6.8 to 7.2 for an aquaponics system.
What alarms me more so is when starting a new system, some people don’t consider a correct grow media for their beds. They think they will go an inexpensive route and use gravel. They never consider if that media will be pH friendly. Then once it’s in, it’s not only disheartening to find out it’s the wrong type, but now they have to go through the time and expense of replacing it. On our next blog post, we will go through the right media to use and how to test it; stay tune.
Depending on the size of your system, you can easily maintain pH or if to small, it can swing wildly. I always like building bigger systems to help control the water quality more so. You don’t have the large fluctuations like smaller systems do.
Fish waste can make the pH be more so acidic and you might need to consider using an aquaponic compatible pH adjuster. If the pH is too high or low, the performance of the system will be effected. Either way, you will see the fish or plants not growing properly or dying. Also, it can severely cause issues with the bacterial growth and that’s a whole other problem.
It’s very important to monitor the pH level each day and to keep it within the neutral range. As mentioned before, pH adjusters can help, but you need to ensure that they are friendly to your entire system. You would not want to harm your fish. Not only does the grow media and fish fecal matter affect pH, the condition of your water does as well. In some areas of the world, the hardness of the water is more so than others. Here in Honduras, I have always been fortunate to have water that is not hard and it hasn’t been an issue for me. If you are dealing with hard water, then consider a different possible source or you will for sure need to use pH adjusters mentioned before.
Remember, anytime you make adjustments to your pH, make sure you make slow changes. Fish dislike sudden changes in the pH and water temperatures. The last thing you want to do is shock your fish; stress can lead to death.
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