Why does Marge have blue hair?

I forgot what episode it was, but it has been said that Marge was born with grey hair. Out of embarrassment as a child, her parents began to dye her hair blue and she's kept it that way. This is what I remember hearing anyhow.

She paint´s her hair
after all she´s grey as a mule since she was 17
Homer says it to his class in the episode "Secrets of a Sucessfully Marriage"

Marge has blue hair because she dyes it that colour. it was featured in the episode when homer starts teaching mariage classes

i dont no i think she died it or was born with ble hair! her hair is really long how can she fit in the car???!!!!!

because marge was born with grey hair and due to embarrassement her parents dyed her hair blue.

maybe she died it blue?

she dyes it

Same reson they are all yellow

She dyes it blue. Her hair is really gray as hell.

because she was born with blue hair

her hair is not blue it's grey it's just died blue... havnt you guys seen the episode where marge goes to the haircut place because she sees her "first grey hair"? It want her first grey hair... it's just that her hair was colored on the outside but her hair is grey on the inside!!!! hope this helps than the other "accurate" responses 

spray paint

Idk but she looks cool