Light that appears blue occurs at wavelengths between 430 and 460 nanometers (billionths of a meter). According to Oregon State University Extension Service, blue light encourages vegetative plant growth.
Red light occurs at wavelengths between 640 and 700 nanometers. OSU also claims that light from the red part of the visible light spectrum promotes budding and flowering in plants.
Plants appear green not because they absorb light from the green part of the visible light spectrum but because they reflect it. White light is white because it contains all colors of the visible light spectrum.
Generally, the more intense light that a plant receives, the faster it will grow. According to OSU, when a plant receives a lot of sunlight, it has a greater food production capacity via photosynthesis.
The more time a plant has been exposed to a light source, the greater it will benefit. In certain climates, plants have adapted to the longer day, shorter night schedule and photosynthesize according to the unusual light schedule.