What is the best way to darken hair using only organic/natural materials?

henna and coffee

What is the best way to darken hair using only organic/natural materials?

Tea

What is the best way to darken hair using only organic/natural materials?

Henna

What is the best way to darken hair using only organic/natural materials?

There is no way to darken without coloring, although it can be done professionally, with a non ammonia color that would not cause any damage at all.

What is the best way to darken hair using only organic/natural materials?

mud.

What is the best way to darken hair using only organic/natural materials?

Your hair is dead anyway... organic/natural is not going to help anything.

What is the best way to darken hair using only organic/natural materials?

Henna is used for coloring, thickening, and to add a protective natural shine. It's derived from only natural plant matter. But here's a problem, it coats your hair and any other chemical processes will not work such as perms, highlights...You could probably get this "Henna" product from beauty supply stores or perhaps from natural food stores in your area. As a matter of fact, you can probably order it online!