Hydroponics is the practice of growing plants in water instead of soil. According to the book Hydroponic Food Production, the first hydroponic gardens may have been the Hanging Gardens of Babylon. Aztec, Egyptian and Chinese civilizations used hydroponic culture to grow food. More recently, NASA has experimented with hydroponics as a source of food in space. Because plants in hydroponic culture do not have to search for nutrients in soil, they grow more vigorously and produce fruit more abundantly. You can grow herbs hydroponically in your own kitchen for year-round use in cooking.
Cut a sheet of Styrofoam to fit into the top of an aquarium. The Styrofoam should fit tightly to the sides of the aquarium so that it will be stable and reduce evaporation.
Cut a set of holes into the Styrofoam that is just large enough to hold a net basket, such as the type that is used in pond gardens.
Fill each net basket with vermiculite.
Remove your herbs from their planting cells and gently wash the roots to free them of the potting mix. Plant the plants in the vermiculite in the net baskets.
Place an aquarium bubbler in the bottom of the aquarium and attach it to a pump.
Mix a nutrient solution according to the directions on the packaging. Mixing instructions will vary among nutrient solution brands. Fill the aquarium with the nutrient solution.
Place the net baskets into the holes cut in the Styrofoam and place the Styrofoam in the top of the aquarium. Turn on the air bubbler to oxygenate the nutrient solution.
Place the hydroponic solution beneath a fluorescent lamp. A fluorescent bulb placed one foot above your herbs will provide you with adequate light to grow your herbs.
Check the pH of the nutrient solution once weekly using paper pH test strips. The pH of your solution should remain between 6.5 and 7.0 so that the herbs can take up nutrients efficiently. To adjust the pH, add phosphoric acid to lower the pH and potassium hydroxide to raise the pH.
Add water to the solution when the aquarium is half empty. Completely change the nutrient solution the second time that the aquarium becomes half empty.