All it takes is baking soda, water and apple cider vinegar. I keep two plastic water tight containers in the shower (make sure they hold at least a measuring cup amount) one with just baking soda in it and the other with the vinegar and water combo.
Also you may have to work with these proportions a little bit to find out what works best for you, because everybody is different. Since my hair is oily I use a little more baking soda then what is recommended but about the same amount of the vinegar and water combo.
Here are the proportions most recommended:
1. Pour about 1 tablespoon of baking soda into the palm of your hand, and moisten it. Massage it into your hair and your scalp. Wait a minute, then rinse. I usually focus the baking soda mainly on the scalp because that is where it gets oily. Make sure you rinse the baking soda out really well otherwise it will be fizzing on your head and you will turn into a science experiment!
2. Combine 1 tablespoon apple cider vinegar (I use Bragg's Apple Cider Vinegar) and 1 cup water in your container. You can do this in advance, so you don’t have to mix it up every time you wash, and you probably won’t need the whole cup for a single washing (I use about a quarter of the container for each time). Give the container a good shake, then pour some of the vinegar mixture onto your scalp. Massage it into your scalp and your hair, wait another minute or two, and rinse thoroughly.That is all! Try it out, it works great for me and it may just do the same for you.