Why Are Greenhouses Not Green?

Greenhouses are enclosures, usually made of glass or other transparent materials, in which plants are grown in a temperature- and humidity-controlled environment. The color of the greenhouse is chosen to maximize the growth potential of green plants.

Transparency

• Greenhouses are transparent, not green, in order to allow full-spectrum sunlight to reach the plants, which maximizes their growth potential.

Etymology

• The term "greenhouse" was first used in the 1600s and is made from combining the word "green," in reference to the color of the many plants contained, and "house," from the shape of the building, according to the Online Etymology Dictionary.

Spectrum of Light

• Plants absorb many different wavelengths of light found in natural sunlight. The wavelengths that are not absorbed, which are in the green portion of the spectrum, are reflected back from the plant's leaves, making them appear green. If the windows of a greenhouse were tinted green, only light in the green spectrum would reach the plants and, since green plants do not absorb green light, they would not thrive.