While you are waiting for the henna paste to set, shampoo your hair. Rinse your hair thoroughly. Do not use any conditioner following your shampoo. You want your hair to be chemical free. Towel dry your hair.
When ready, apply the paste in sections to all of your hair beginning from the roots to the ends. Cover your hair with the plastic cap and wait approximately 45-60 minutes. You can use a blow dryer if you like to help bake the dye onto your hair strands, just be careful not to overheat and melt the plastic cap.
Rinse the henna goo thoroughly with water. Towel dry your newly colored hair. Do not shampoo for at least 24 hours.
Hint: Henna stains, so be sure to wear plastic gloves. It is also wise to apply petroleum oil along the hairline to protect your face, ears, and neck from discoloration. It is okay if you get a little staining on your skin. Stains on your scalp and skin should not last for more than a day or two. The dye on your hair should last four to six weeks.