I only use henna/indigo I get on Amazon now. I would never put peroxide in my hair ever again.
Bleaching then dying or just dying my hair was way too toxic.
I only need to leave Henna on for about an hour and I get the color I want.
Last time I used henna the indigo turned my hair green I was freaking out I did not know what to do and did not dare to even go outside.
An hour later the air had oxidized the green color and turned it the warmest shade of brown.
You cannot put henna on peroxide treated hair or it will literally melt your hair.
You have to wait till it all grows out and cut the color treated hair off.
You can henna your hair even if it is very short crew cut length because it does not burn your scalp.
I hope I am not telling you things you already know.
Youtube has a lot of great videos on how to use henna/indigo.
You pretty much can just add water and put it on your hair.
Some people add a lot of conditioners and lime juice etc. but consider even straight henna and indigo is much gentler on your hair and scalp than peroxide ever is.
Got to wait till it grows out and trim it to try henna though. I will never ever go back to peroxide based dyes and bleaches.