Light color affects both the rate of growth and flowering cycle of a plant. Botanists and recreational gardeners use various light sources to manipulate the growth of a plant.
The chlorophyll in plant cells absorbs light to perform photosynthesis which allows plants to grow. Chlorophyll molecules most efficiently absorb light in the red and blue wavelengths and least efficiently in the green wavelengths. Plants have a green color because the majority of green light is reflected by the chlorophyll. Therefore, red and blue lights encourage growth and green lights inhibit growth. Fluorescent lights produce mostly blue light and encourage leaf growth, while red-and-blue combination lights encourage flowering.