Plant Growth & Colored Lights


Light is one of the most important factors in healthy plant growth. Plants, unlike humans, can make their own food through a process called photosynthesis. The correct color of light, along with water and nutrient soil, will provide a plant with the sustenance of life.

Light Quality

Light quality refers to the color of a light. Light color is determined by its wavelength, or how it travels through the air. Sunlight is the most pure light, providing all the possible wavelengths that light can provide. Wavelengths of light quality can be red, yellow, orange, blue, green, indigo and violet.

Colors Plants Prefer

Plants prefer blue and red light. These two color qualities have the greatest influence on how a plant grows. Blue lights' responsibility is to promote leaf and vegetable growth, while red, when combined with blue, will make a plant flower.


Colored lights help promote photosynthesis indoors, where sunlight cannot reach a plant as well as if it were grown outdoors. Plants use the light from grow lamps to produce sugar, which is stored or used right away if the plant requires food or is stressed.

Growing Lights

Fluorescent light, which is cool and white when looked at with the naked eye, is mainly blue wavelength. Fluorescents will encourage young seedlings to grow quickly. Incandescent lights are high in red light, but produce too much heat for indoor growing. Fluorescent grow lamps that emulate the light of the sun are available, but these are very expensive.


Light duration is an important factor in plant growth when using grow lamps. Long-day plants form flowers only when light in the day is more than 12 hours, while day-neutral plants will grow regardless of how long they receive light. Supplemental light can be used to extend or shorten the period of flowering on a plant. This is easy to control in a colored light environment.

Keywords: plant growth, colored light, grow lights

About this Author

Cleveland Van Cecil is a freelancer writer specializing in technology. He has been a freelance writer for three years and has published extensively on, writing articles on subjects as diverse as boat motors and hydroponic gardening. Van Cecil has a Bachelor of Arts in liberal arts from Baldwin-Wallace College.