We know that light has color, which we normally don t see. We don t usually think much about the color of light because we normally can t see the difference. We do know that one particular color is very bad for our eyes and our skin. Violet is the first color. Can you tell me the others, and I ll write them on the board in order.
Plants mainly use the blue and red portions of the color spectrum.
That is where chlorophyll pigments absorb the most light. Light intensity is measured in footcandles. A footcandle is the amount of light one standard candle gives off one foot away. Plants grow best if grown in high light for 9 to 10 hours per day. If the light cannot cast a shadow it is too low for a plant to survive.