Question

why do plants look greener after rain

Answer 1

If the grass looks greener after the skies have cleared, your eyes aren't deceiving you.

There are several reasons rain helps lawns green up, said Jennifer Knoepp, a research soil scientist with the USDA Forest Service, SRS, Coweeta Hydrologic Laboratory in Otto, North Carolina. Both of those reasons involve nitrogen, but one of them might surprise you.

After it rains, there's typically more water available in the soil for plants, Knoepp said. When plants take up that water, they are also taking up nitrogen from the organic matter that's in the soil.