I started making my own soaps and lotions to help my Husband who has exczema. So I understand wanting to stay away from chemicals. If you can find a person who sells shampoo bar soap, I think that would help. Natural soap does not strip the hair of all its natural oils. In fact, I find that I get a buildup and use a regular shampoo every now and again. Also, no matter what I use I always use a vinegar rinse after the shampoo is rinsed out. A basic vinegar rinse is 1 to 2 tbsp of vinegar to 2 cups of water. I have a bottle in the shower and just add some to my rinse cup and add warm water from shower. You can also make a tea of various herbs to help with shine and color, then add the vinegar to lukewarm tea.
A conditioner that I like to use is one of my natural lotions. I put it on before washing my hair, then wash and then vinegar rinse. Sometimes if my hair is especially dry, I will run some light oil (sweet almond oil) thru my wet hair. I use a very small amount otherwise you would look like you need to wash your hair again.
Do NOT wash hair every day. Try every other day. I wash my hair every 2 days usually. Washing often strips the oils from the hair. As for curly hair, I don't have too much advice since I have very straight hair, but I have heard that instead of washing with shampoo, some ladies just wash with conditioner. I could say if it works one way or the other, but I have heard of a book or something like it called "The Curly Girl Method". You might want to look at that.