AHL's Guide to growing
In an outdoor environment, nature gives the plant what it needs to grow: sunshine to power photosynthesis, mineral elements to convert into starches and sugars, water to carry food through the plant, and carbon dioxide for plant respiration. But some of these provisions may be more or less than the plant needs, so the resulting environment is seldom "ideal." In a controlled indoor growing environment (whether a large greenhouse or a small home grow room), you—the grower—must supply all of what the plant needs. In the beginning, this method may seem like more work than gardening outdoors, but the ability to control all of the plant's growth factors can result in much greater yields in a smaller amount of space.