Grow vegetables or ornamental plants all year long with a hydroponic system. Hydroponics, a growing method that requires no soil, often makes use of a substrate to support plant roots. Supplemental lighting may be necessary, unless you have a well-lit location for your hydroponic garden. If you are new to hydroponics, start by growing lettuce, greens or herbs -- plants that tend to do well in this environment.
Cut the Styrofoam piece so it is about an inch smaller than the aquarium opening all around. Cut approximately 2-inch holes in the Styrofoam to fit the plastic cups. Space the holes about 4 inches apart. This will be your floating platform for holding the plants.
Use the nail to poke four or five holes in the bottom of each plastic cup. Line the bottom of the cups with a layer or two of cheesecloth to prevent the perlite from falling through the holes. Fill the lined cups about three quarters full of perlite. Plant your desired seeds in the perlite.
Cover the outside of the aquarium with aluminum foil to shield it from the light. This will prevent algae growth and preserve the nutrient solution.
Mix the nutrient solution according to package directions and fill the aquarium with it to about 3 inches from the top.
Place the airstone, with airline attached, in the aquarium. Hook it up to the air pump and plug it into an outlet. Check to make sure it is bubbling.
Set the floating platform in the filled aquarium. Place one filled plastic cup in each hole. Now it’s time to watch your hydroponic garden grow.
When the water level is down to about half the original amount, refill the aquarium with water. The second time it is reduced to half full, drain the water and refill it with a fresh batch of nutrient solution.