What makes grass green?

The green color in grass-and in most other plants-comes from chloroplast within the cells, each of which contains four different colors or pigments. These are: chlorophyll a, which is the strongest and is blue-green; chlorophyll b, which is yellow-green; xantophyll, which is yellow; and carotene, which is orange and gives carrots their bright color.

Grass goes from light green in early spring to dark green and brown in summer and autumn because the amount of each pigment changes, like the paint on a palette, to mix new colors.