What is your actual goal? Are you wanting a temporary or semi-permanent result? Or are you looking for an all-natural method?
Manic Panic is a wonderful semi-permanent vegan hair dye. Kool aid, coffee, walnut, tea, and "casseia obovata" are all chemical-free methods for a temporary result. Henna and Indigo are plant dyes for more permanent results. Henna is a copper-red, and Indigo is a blue-black, but you can make different mixes for different brown and red tones.