Most growers are plastic, and metal in usually be used because it can poison the plants. The tub can be any size, and larger tubs can be made of adobe or mud and lined with a waterproof material. Smaller growers can be made of disposable cups or food containers. Placing the Drain Hole To create a hydroponic grower out of the tub you will need to create a drain hole on a side. The drain hole can be placed anywhere along the side, and where it is placed will determine the water table in your grower.
Plants grow with their roots going towards the water table.
The plants vary in how much area they want in the ground before they find a water table and so where you put the hole in the side of the tub will determine which type of plants will grow best in the tub. Deciding where to place the drain hole determines what kind of food you can grow in the tub. A hole was cut one half way up the side of the tub for corn. A hole is cut in the tub, which is large enough for a drain fitting. The drain hole will allow excess water to drain out of the system and be available to use later.