Ive been hennaing my gray hair for years now. I always mixed my henna with straight lemon juice. The last two times I ended up using key lime juice because I have a key lime tree and decided to use up the limes rather than go out and buy lemon juice. I noticed my hair was lighter all over than normal after both applications and it didnt oxidize much darker like it normally does using lemon juice. I always do whole head applications, I never bother just doing the roots. So I thought it was interesting that even the previously hennaed hair also lightened up. For both previous applications using lime juice I probably let my key lime / henna paste sit for 10-12 hours before using which is what I normally do with lemon juice. I dont like the light look, I like the deeper color I used to get using lemon. Is there anything else other than lemon I can use to mix my henna with that will produce that typical deep rich color? If I mix henna with straight vinegar will it be the same as mixing it with lemon? Or do you cut the vinegar with water? How does it work when using vinegar? And can I use plain white vinear or do I have to use apple cider vinegar? Or can I actually use brewed tea like lemon juice and get the same intense color? Ive alwyas bought my henna from tapdancing lizard - I purchase whichever has the highest lawsone contenet at the time I'm buying. I dont recall the name of the latest henna that I bought - but it came from tapdancing lizard and was the highest lawsone content one they had.