There are many options for Aquaponics Grow Media. All of them have their benefits and their draw backs. I’ll highlight each one and discuss the situations in which you would choose to use it.
1. Expanded Clay Pebbles-
Expanded Clay Pebbles is probably the top option for Aquaponics grow media. The benefits of using Expanded Clay Pebbles are that they are very light, they don’t break down, they resist molds and fungus and they are the perfect size to allow plants to grow without restricting water flow. They are also round which makes digging through them to plant or maintain the garden easy on your hands.
The major downfall of this product is cost. It is typically a dollar a liter and you need about 200 liters for one grow bed. Small grow beds are ideal for this product or if you manage to score buying this product in bulk, go for it!
2. River Rock-
River rock as an Aquaponics grow media is a very good option. Buying it locally from a landscaping store and having it delivered is much cheaper than Expanded Clay Pebbles. This product is ideal because it is rounded and makes digging around in the rock easy. As long as you’ve gotten a large enough size river rock (1/2″-3/4″) it won’t clog your system.
The major drawback to this product is weight. Once you fill a grow bed with river rock it isn’t going anywhere except down…if you haven’t made your supports strong enough. Shallow beds, beds placed on the ground, or very well supported beds work best with this media.
3. Coconut Coir-
This option is one of the more inventive options for your Aquaponics grow media. It boasts near perfect pH levels, is rot resistant, light weight and very eco-friendly. This medium is great for water flow, holds water well, drains well, and is very easy to dig in while maintaining your plants and system.
The down fall of this product is that it is often very high in sodium. Be careful to find a product that has reduced the sodium levels. It is also anti-microbial, which can harm your bacterial levels in the tank which is bad for the fish. Placing some coconut coir on top of a gravel medium would likely be a good solution.
4. Lava Rock-
Using lava rock as an Aquaponics grow media is a very good option (this is the option I chose in my own grow beds). Lava rock has a reputation for being much lighter than river rock and much easier to source than the expanded clay pebbles or the coconut coir. This rock will have little to no affect on any of the pH levels in your system. It is the perfect size to allow water flow without restriction and for plants to grow with good support.
Lava rock has a few cons but they are easily dealt with. This rock is typically very dirty and needs to be rinsed well or the dirt will wash into the system. The lava rock is a very difficult media to dig around in, obviously. Another thing to consider is if it is a local product. Depending on where you live you might have an easier time finding coconut coir than rock.
Using water as your Aquaponic grow media is typically known as having a floating raft bed. In this situation you would forgo any grow media whatsoever. Instead you would purchase a Styrofoam board, cut holes out for the plants, place net pots in the holes and grow your plants straight out of the net pots, in the water. This is ideal for leafy greens like lettuce, cabbage and herbs.
The down fall of not using a grow media is that you will need to add another filter to strain out any solid particle from your fish. If left in the water they will clog up the roots of your plants and your plants will not be able to grow properly. Also, fruiting plants do not do as well in this setting. They typically need a sturdier support system. Placing a floating raft bed among several other grow beds could be the perfect way to harness the benefits without dealing so much with the downfalls of grow media.
I’ve read many forums where people talk about the media they are thinking about using for their grow beds and I’ve heard of some very interesting ideas. One man wondered if he could use glass marbles or even shredded glass from a recycling plant. The verdict here was NO! The shredded glass will cut even the most careful person and runs the risk of small pieces floating through the system and getting into the fishes’ lungs. Bad thing. Glass marbles are also not so good of an idea because they would allow sunlight through the whole bed, adding to the algae growth.
Someone else asked about a ton of nylon rope they had sitting around and someone else mentioned they used cotton in their net pots. If you happened to have a huge collection of buttons that you had no other use for, they would make great grow medium too! The idea here is that you can use what you have.
Choosing your Aquaponics grow media doesn’t have to be a hard decision. Weigh your cost needs with the availability in your area and any of the options I’ve presented are very viable.
If you have used any media that is not on my list, comment below! I’d especially love to hear if you used an unconventional product as your grow media!
Continue Reading about The Best Fish For Aquaponics Systems