The Right Intensity

The intensity of light that a plant receives is determined by the wattage of the bulb and by how close the plant is to the light source. Just as plants differ in their need for certain colors of light, they also differ in their need for light intensity. Typically, those plants that are native to tropical jungles or shady forests do not require as much light as plants that evolved in dry, sunny climates such as the Mediterranean or southern Mexico.

Most flowering houseplants, like African violets and begonias, are happy being 10 to 12 inches away from a light source. Non-flowering, like ivy or philodendron, plants can be placed as much as 36 inches away from a light source. But many flowering plants, such as orchids, gardenias and citrus, as well as most vegetable plants, require a much higher light intensity to flower and produce fruit.