Different experts have different viewpoints when it comes to the aquaponics grow bed depth. While the majority of the media based aquaponics growers say that you should have about 12’ of media, with the top 1-2” being left dry to reduce algae and fungal growth. There are some other too, who are in favor of growing successfully in substantially less than that. These things are very confusing, so how deep should your aquaponics grow bed be?
The deeper the bed is, the more costly it will be. The costs of supporting the weight of the extra media need a larger fish tank to fertigate that entire media. In addition, if you go for some 4-6” depth you can use standard hydroponic flood and drain trays which are very difficult to find.
- Work great for limited plants: If you going to grow short-lived plants such as lettuces and greens, shallow beds work great for such kinds of plants. But when it comes to longer lived or deeply rooted plants such as cucumbers, indeterminate tomatoes, melon, and corn etc. they don’t work nicely. These plants require enough nutrients and bacteria for relatively long life. Shallow beds can’t provide the base for it, also the space for large root zones. If you want to grow the limitless variety of plants, media based aquaponics can be a great choice, because average depth of such kinds of aquaponics bed is 12”.
- “Dead zones” and the need to clean your beds: By the time, in deep beds, a layered ecosystem establishes which prevents the developments of the dead zone in the bed. You never need to clean out your grow bed as thriving environment flushes with beneficial bacteria and worms and plenty of space help roots to grow. They along with the plants, do the cleaning for you. You can experience it at about 12” of media depth, because when there is enough space for a robust ecosystem to establish itself, then all the elements of that system thrive and become self-sustaining.
These are some limitations of aquaponics bed depth. It depends on your needs that what bed depth will be more suitable for you. If you are growing only short-lived plants, you can go for shallow beds. But if you are planning to grow deeply rooted plants, then you need more depth in your beds. It is suggested that 12” of media depth is just perfect for all kinds of plants.