This is the first henna I ever used on my hair and I've been henna-ing now for a few years. I am biracial and have thick 3c curly hair that is prone to severe dryness if not properly moisturized and cared for. I was interested in henna for moisturizing/strengthening of my hair and also to add some red coloring.
Since using the henna for african hair I have also tried Jamila henna (HATED IT), Karishma (very nice) and Godrej Nupur (also great). When I henna I do it on dry, unwashed hair. The night before I will oil my hair with brahmi oil (from garrysun.com). I mix the henna with water and let it develop overnight.
The next day before I apply the henna I add Amla oil (from garrysun.com) and Hesh amla powder (keeps the henna from loosening my curls too much). Sometimes I add conditioner (like Oyin Honey Hemp) to make more of a henna gloss. You can also add an egg for protein. I leave my henna on for at least 4-6 hours then wash out with a cheapy bottle of VO5 conditioner followed by a heated deep condition with Aubrey Organics Honeysuckle Rose and coconut oil.
I have recently started mixing indigo (from mehandi.com also) into my henna to get a dark brown color instead of the auburn. I always have good results with henna/indigo from mehandi.com and I'm now a HENNA and INDIGO ADDICT!!!!
ETA: Sorry for the length!! Didn't realize until I saved it how long it was . . . .
I happened on hennaforhair.com about a year ago while trying to find more natural hair coloring to blend my gray hairs. My hair is naturally a medium dark chestnut brown, naturally curly, with about 25% gray and, at the time, old chemical highlights and lowlights. After reading about the different mixes of henna, indigo, etc. to try to achieve this, I decided to take the plunge and ordered body-art-grade henna for African hair (though I am not African American) from mehandi.com because it was the type that was supposed to best cover grays. I chose BAG henna because it is pure, unadulterated vegetable dye with no added, metals, salts, or compounds.
I used a mix of equal parts henna:cassia:Indigo, hoping to blend the old high/lowlights, the grays and my natural hair into something close to my natural chestnut brown. I added a little amla to the mix also as it's supposed to help retain curl since henna can sometimes relax it. I used lime juice (that was what I had on hand) for the acid the first time. I mixed the henna and cassia with lime juice and left overnight for full dye release, then I mixed the same amount of indigo with warm water and a little salt (helps set the indigo's color, just like dying clothes), added it to the henna/cassia mix, applied as much as my hair would take, covered with a plastic cap and froze the remaining mix (that inactivates the indigo, so I had to add new each time I used some of this frozen mix). I left the mix on my hair for about four hours, rinsed thoroughly (perhaps the hardest part - takes several rinsings to get it all), then shampooed, conditioned well (a must), and styled as usual. Tip: "co-washing", i.e., washing with conditioner loosens the henna and makes it easier to rinse out. Be aware that all of that plant matter can make your drain slow (I use Whink Hair Clog Blaster afterward and it gets it going quickly again - much better than Drano or Liquid Plummer. One cup for 20-30 minutes works better than a half bottle or more of either of those!)
I was very well pleased with the results and did it all over twice more like this to further blend the highlights over the next 3 months, but after that first time, I used chamomile tea for the acid - plenty acidic enough for dye release, but much easier on my hair. After that I only did root touchups for a while. Now, since that gave me a little more auburn color than I really wanted and more noticeable roots than I'd like, I've switched to just doing henna glosses, which I've since learned about. I mix a couple of tablespoons dry henna into 1 to 1.5 cups cheap conditioner, add about a tablespoon of indigo and a teaspoon of salt mixed with enough warm water to dissolve it and release its dye, then apply it all over my hair with a hair applicator bottle. I cover it with a plastic cap and leave it on for about an hour. This gives my gray hairs a slight reddish gold color and deposits no noticeable color on my natural color. I've had all the old high/lowlights cut off by now and now just have the all-over full-dye-released henna to grow out, but it's no big deal and isn't really noticeable to anyone but me.
Overall, henna is very forgiving, even when using it full dye released. When doing root touchups, you can overlap old henna with new without mishap - no definite lines of demarcation or anything. BAG henna can be colored over with chemical hair color safely and can be used over chemical hair color safely. If, however, you used indigo in the mix, be careful about coloring over it with chemical color - read up about all of this at www.hennaforhair.com.
I wish I had known about doing the henna glosses from the beginning, but regardless, I'm glad I discovered BAG henna and gave it a try - I'm much happier now - as is my pocketbook - than when I was having regular foil highlights done. And I wasn't fooling anyone, those grays were still shining right thru, LOL! And henna is actually good for your hair and scalp. It strengthens your hair, but you do need to moisturize/condition well afterwards. I don't get those full strengthening benefits from these weak henna glosses I do now, so I sometimes do a regular cassia treatment for the same benefits without color.