Moving rural meant well water, and well water meant even the lightest and most cleansing shampoos no longer cleaned my hair. All the extra ingredients cling to the hair shaft and my hair tarted to look always greasy and matted down.
So I went really basic!
Ingredients: baking soda, water (optional: fragrance, color). Most recipes advise a 1:3 ration, baking soda to water. My hair is too fine for that concentration and I had trouble getting the baking soda to the scalp when I tried to use it in the shower.
I tried mixing up a 1:2, but it was still too thin so I eventually mixed 1:1. I decided to bring it to a boil to get the baking soda to stay in solution)
Let it cool. I then pour it into a measuring cup because it has a pouring spout.