Hydroponics is the science of growing plants without soil. The plants are either supported from above while the roots float in a nutrient solution, or they grow into a soil-free substrate. The substrate must be capable of supporting the root structure of the plant as well as holding the nutrient solution. The substrate must also be loose enough that air can pass freely through it. Sand and gravel are both ideal choices for substrate material in a hydroponic system.
Place the net baskets face-down on the lid of the tub and trace around the rim with a marker.
Turn the net baskets over and place the bottom of each basket into the center of the circle you traced in Step 1. Trace around the bottom of the basket.
Cut out the center circle from each tracing on the lid with a utility knife. Cut tabs into the tub between the inner and outer circles to hold the basket in place.
Place the valve on the side of the tub. Cut out a notch into the lip of the lid that will fit around the valve.
Place one basket into a hole in the lid and place the lid onto the tub. Hold the marker in your right and and slip your hand through a second hole. Place the marker against the bottom of the basket and mark its level on the inside of the tub. Transfer this mark to the outside of the tub to serve as a water line.
Place the three air stones in the bottom of the tub and run tubing from the valve to the air stones.
Mix a nutrient solution of 3 teaspoons per gallon of water. Fill the tub with nutrient solution up to the water line.
Place all six baskets into their holes and fill with a substrate of gravel or sand. Make a planting pocket inside the substrate. Rinse the soil out of the roots of a plant and place it in the planting pocket. Cover the roots with substrate material.
Run a hose from the valves to an air pump. Turn on the pump to circulate air through the hydroponic system.