WHY ARE PLANTS GREEN

Plants are green because they have a substance called chlorophyll in them. Chlorophyll absorbs wavelengths of light with wavelengths around 450nm and again around 650nm. In other words it absorbs reds and blues. The only light left to reflect off the plant and back to your eye is green. This is why plants appear green.

But since they appears green—bouncing back green and yellow light waves—it means it's not 100 percent efficient at absorbing all of the sun's rays.

Plants get their energy to grow through a process called photosynthesis.  Large numbers of chlorophyll molecules acts as the antenna that actually harvest sunlight and start to convert it in to a useful form. Is where the absorbent properties of the chlorophyll molecule come into play.