Quality refers to the color of the light emitted by a light source. The sun radiates light in all the colors of the rainbow. Plants need most of their light from red and blue areas of the color spectrum. Duration or photoperiodism, refers to the daily amount of light to which plants are exposed. Most plants need 14 to 16 hours daily.
Intensity refers to the amount of light available in a given area.
Of all the factors limiting photosynthesis, intensity is the most critical. Consider that outside on a sunny day, the light intensity is somewhere around 10,000 footcandles. The average indoor light level, on the other hand, is 50 to 150 footcandles. Many different types of artificial light are available for indoor gardening. If you choose a light source that emits the full spectrum of light, your plants should thrive.