Hydroponics is a method of growing plants without the use of soil. Plants are provided the 13 elements they usually receive from the soil in the form of a nutrient solution. One of the simplest hydroponic systems is the use of a reservoir that holds the nutrient solution and provides it back to the roots of the plant. The plants are suspended above the reservoir in an inert growing material such as perlite, called an aggregate by the University of Illinois. The aggregate is held in mesh pots, which are available from most gardening centers.
Paint the inside of an old fish tank black to keep light out of the nutrient solution and prevent evaporation. Allow the paint to dry.
Connect an air stone to a piece of air tubing and place the stone at the bottom of the fish tank.
Cut a piece of foam so that it fits into the top of the fish tank but does not fall in. Trace the bottom of the mesh pot onto the foam and cut out circles to hold the pots in place.
Connect the tubing from the air stone to the air pump outside the fish tank.
Mix together your nutrient solution according to the package instructions. Test the pH and ensure the pH is between 5 and 6.
Pour the nutrient solution into the fish tank so that it is filled three-fourths of the way.
Put your plants into the mesh pots and cover the roots with perlite.
Place the foam board on top of the fish tank and insert the mesh pots into the cut holes. The bottom of the pot should be 1/4 inch above the solution. Turn on the air pump.
Replace the nutrient solution every two weeks to prevent the nutrients from condensing.