Hairs light on top and dark on bottom after using red hair dye, what do I do?

Hello, I dyed my hair a fairly vibrant red and it turns out it's a lot lighter on the roots/top and the lengths of my hair are still quite dark. I really love the colour that's on top but how do I make it all go one colour? I was thinking about just putting another red dye on, but just on the ends. What's everyone's opinion? Many thanks :)