It’s been a while since I talked about our aquaponics system, but we have indeed been working on it and it’s actually running very well. We’ve had our beds filled and even have plants in it but I putting the events down in words has taken a while longer.

When building an aquaponics system, there are several growing media which can be considered. You may be lucky enough to have an endless supply of small pea gravel or river rock in your backyard. Or perhaps you will be using lots of growing tubes instead of large beds so you want something more soil-like to work with. But whatever you end up using, it needs to be something that will drain well so that the plant roots don’t get waterlogged and begin to rot.

Most people, including us, go with choose to fill their aquaponics grow expanded clay pebbles. Our pebbles are 4-16mm (the most common sized used since it’s small enough for the roots to move easily through) and have a high porosity and air content. They can be used forever because they don’t rot or break down, and are not susceptible to fungus. Plus they also weigh a lot less than something like pea gravel which means your grow bed construction doesn’t need to be quite as robust.

aquaponics growing media

Pea gravel or small river rock is another good option for an aquaponics system and a lot of people use it because it’s fairly inexpensive. But it can be quite heavy so you’ll need to take that into consideration when you build your grow beds.

aquponics growing media

I’ve also heard people mention using materials just as peat moss, coconut coir, rockwoll, perlite and vermiculite. In most cases (and especially for hobby purposes like our own), these materials are stuffed into small plastic baskets which will then have seeds planted into them. This keeps your seeds from accidentally getting flushed away or drifting down to the bottom of the grow bed. You also have the ability to start your seeds earlier indoors where you can better control light and temperature, and then transfer them outside when they are ready (much like with normal seedlings for your garden). We currently use rockwool cubes which can be purchased at any hydroponics supply store. The cubes are much more compact than rolls of rockwool that you would find in the home improvement store so I haven’t determined how one might make these themselves. But if you have a lot of coconuts in your yard, you should certainly try making your own starter pot filler.

If you have an endless supply of any of these recently mentioned materials, you might also consider using them as the entire grow bed media. Peat moss and coconut coir seem to be the most frequently used of these but you must consider that they will eventually begin to breakdown and will rob your system of some oxygen. Peat moss is also very susceptible to harboring mold and fungi which you definitely don’t want.

Up next, you’ll get to see our process of washing the clay pebbles, filling the bed, adding trim to finish off the bed and adding plants.