For a basic system, you'll need grow medium, which can be as simple as clean gravel; and an irrigation system, which can be as simple as a wicking system, which draws water and nutrients to the root zone through a wick made of felt or cotton robe, for example. For more water-intensive plants, the Nutrient Film Technique is an excellent choice, where nutrient-rich water is circulated through a channel and roots reach down into the channel.
The more complex hydroponics setups require pumps and drains, as well as a reservoir system with aeration where nutrient levels are tested and adjusted. Depending on your location and the seasons you're producing, you may need supplemental lighting and heat. Large, sophisticated setups may require motorized and computerized systems to move hanging plants around for easier access, sensors to ensure that plants are receiving enough moisture, and automatic testing equipment to determine whether the nutrient and chemical balance in the nutrient solution is optimum.
