Can plants see blue light?

[FishySituation]

I’ve heard Cory say that plants can’t see blue light and only algae can in a live stream or video. Is this true and if it is then why do companies even put blue leds in lights? I’m battling this hairy green algae growing on my val and some other plants. I have no idea what type of algae it is but I can only describe it as a dwarf green hair algae and it’s not regular green hair algae.

[Jack.of.all.aquariums]

Aquarium Leds use a range of colors for looks. If you buy an led strictly for growing plants they are usually very heavy on red lights with some blue mixed in. Algae can grow quite prolifically with only blue that's why blue night lights tend to cause issues for people. Blue LED are used to make white leds so they are cheaper. I personally like my tanks to be a bit more on the blue end of the spectrum.

Aquatic plants aren't as studied as crop plants but blue light is often used to regulate growth and flowering in various ways. 

Here is a short write up about the effects of blue light:

https://www.canr.msu.edu/floriculture/uploads/files/blue-light.pdf

[Garren]

This thread should answer your question on blue light. Cory chimed in on the thread as well.