Bloom Blog

Why Plants Are Green


I never paid much attention in science class.

Actually, I didn’t pay much attention to any class in high school. I was extremely disinterested in having to sit for 45-90 minutes straight, and when I did stay seated my body was present, but my mind was not.

I look back at those times and how differently I would treat education now that I’m older. Maybe I paid more attention than I remember, but if I did, the knowledge didn’t stick. Not all is lost, however. Because of my complete disinterest in learning at a younger age, everything that I am learning now is stuff that I’m extremely fascinated by. 

One thing that crossed my mind a couple of years ago was the very obvious, but not often asked question: Why are all plants green?

Some may immediately recall the answer because they learnt it in high school science and have held that knowledge ever since, however, since you’re reading this post I can safely assume it’s something that you, like me, never learnt or didn’t retain.

So, let’s learn this amazing stuff together.

The sun is so rad(iant)

To learn why plants are green, we actually need to understand light. Light from the sun is actually energy that we classify as radiation, and different wavelengths of radiation produce different colours. So, plants actually absorb that radiation and eat it as food. Nom nom nom.

We call this process Photosynthesis. I’m sure you’ve heard of this before, but not too many people know what it is. In order to keep this blog short, I’ll explain the entire amazing process of photosynthesis in a future post, for now just know that the energy from the sun we call radiation turns into food for plants through photosynthesis, then plants expel oxygen for us to breathe.

It’s very cool and very fascinating. 

During the process of photosynthesis, something called chlorophyll shows up. During photosynthesis, chlorophyll captures the sun’s rays and creates sugary carbohydrates or energy, which allows the plant to grow. 

Chlorophyll captures the sun’s radiative energy, and converts it to food, but there’s a catch: it only captures each end of the visible light spectrum.

Good ol' Roy

Remember ROY G. BIV? In case you don’t, it’s an easy way to remember the colour order of light (aka radiation) that we can see with our eyes. Red. Orange. Yellow. Green. Blue. Indigo. Violet. Notice what’s in the middle? Green.

So plants during photosynthesis absorb each end of the visible spectrum (red and blue) but as it moved closer to the center, it doesn’t absorb the colour, instead it reflects it. So plants eat Roy Biv, but leave the G out of it. Every plant you see is reflecting green, it can’t absorb it and convert it to energy, so it reflects it instead. 

And that reflection is what gives us the beautiful, green, luscious plants we all know and love.

Pretty cool, huh?