Grow beds are an intricate part of Aquaponics because that’s the container where the vegetables grow. Grow beds come in many different forms and configurations but the principles remain the same for each type regardless of whether you built it yourself using wood, fiberglass, concrete blocks or plastic 55 gal drums cut in half or even plastic storage containers from the local family store. They can be any width or depth desired by the Aquaponist in accordance with what they are growing.
1) A handyman special grow bed constructed of wood resembling nothing more than an open top box is common and practical. The width can be whatever is desired but the depth of the should be a minimum of 12″ to allow for growth of the roots.
2) Food grade plastic barrels cut in half, either vertically or horizontally.
3) Food grade plastic containers with metal frames have been used as a combination of fish tank and grow bed.
4) Commercially manufactured grow beds are available from a number of manufactures
Grow beds are equipped with inlet and outlet fittings to attach PVC or rubber tubing to. This allows for the nutrient-rich water to be pumped from the fish to the grow beds and then back to the F/T (fish tank).
One of the fittings that are commonly used is called a Bell Siphon.
This apparatus can be built from materials purchased from the local home building supply company. Its function is very simple. It is the outlet for the grow bed and functions as follows. It allows nutrient-rich water to be pumped from the F/T into the grow bed to the Aquaponist’s desired depth. Once the desired depth is reached, a siphon is created by the Bell siphon and the water in the grow bed is then siphoned out via the Bell siphon until the grow bed is empty of all water, then the process is started all over.
The amount of time it takes to fill the grow beds to the desired depth is determined by the GPH (gallons per hour) and HR (head rate – the gph the pump will pump at a given height) rating of the pump being used. Naturally, the more GPH the pump will pump and the stronger the HR, the faster the grow bed will be filled.
Growbeds contain media in which the plants are placed. The media is inert in that it does not contribute any nutrients to the plants. Its main purpose of media is to give the plants something to anchor their roots in to give them stability. Some examples of media are shown below, however, other types of media have been used.
2) River Gravel
3) Pea Gravel
Hopefully, at some time in the future, I will explain complete with specs, how to build your grow beds out of lumber, namely 2 by 4s, 4 by 4s and 4′ X 8′ sheets of plywood and 6 mil black plastic.
Graphics courtesy of Google Images