There are many different types of aquaponics grow bed containers that you can integrate within your system. Before Julie and Jarrod jump into building their setup, they sat down and did a little pre-planning on what will go into a sturdy and useful container.
The first thing they considered was the weights of everything encompassed in their aquaponic grow bed containers. The grow bed must be sturdy enough to withstand the weight of the aquaponics grow media (for example, clay media = 450g per liter), water (1kg per liter) and plants. There is also added force from the constant filling and draining of water and expansion of plant roots. Jarrod and Julie want to purchase strong and thick material that can handle this.
They also want to choose non-toxic and safe material for food as the aquaponics grow bed will be the home for plants, bacteria and worms.
Also take into consideration that the grow bed should be deep enough for a wide variety of plants to be grown and to have adequate filtration. The standard is 30cm deep.
Grow Bed Volume
Fish tank volume governs the maximize size of your grow bed. The plants need the fish waste to thrive. The bigger the grow bed, the more fish waste required to feed the amount of plants. You need enough fish to support your plants. In general the recommended grow bed to fish tank ratio is approximately 1:1. The fish tank volume should approximately equal the volume of the grow bed. Think of this ratio in gallons per cubic foot; use 6 gallons (22 liters) of fish tank to every cubic foot of grow bed. For example, a 50 gallons of tank water would be able to support 6 to 8 cubic feet of grow bed.
The grow bed is where the media for the growing of plants resides. It also houses two (2) sensors – first being a Media Probe and the other being a Temperature Probe. Also located within the grow bed is the Root Clogging Preventer Mechanism which covers and allows for the water return to the fish tank through the return opening – this is a major problem no one talks about in aquaponics – roots clog everything.
Unless you plan for the root clog problem, systems will fail because they are under designed. The last item found in the grow bed is the Overflow Preventer and water delivery mechanism. Having the overflow preventer in the grow bed will not let any water escape from your grow bed should the grow bed becomes over filled or if a system problem is encountered.
A Word About Metal Containers
Julie and Jarrod can not stress enough about not using metal containers, not even galvanized metal, for either the grow bed or the fish tank. Metals can quickly corrode, throwing your system off-balance by lowering your tank’s pH. Metal containers may also leach undesirable chemicals into your system. Copper and zinc are particularly dangerous for fish.