The indoor marijuana grower may be able to harvest three to four crops a year and may receive $300 to $400 an ounce. Hydroponics offers the grower a way of controlling marijuana production. Hydroponic growers must keep the pH of their solution within a specific tolerance, keeping in mind that marijuana plants grow at a pH level between 5.6 and 6.2. The use of cloning techniques to produce only female plants and hydroponic methods of growing marijuana are discussed. The importance of light and air control when growing marijuana plants hydroponically is emphasized. 7 photographs and 2 illustrations