Good morning Octo.
Condition of hair is determined by genes and what you eat. Foods containing vitamins of the B complex, especially pantothenic acid of the PABA group; a lack of iodine can be detremental, whereas addition of brewer's yeast and wheatgerm are recommended. Dry hair should be washed only once per week with a conditioning treatment once every three weeks. You could use a dry shampoo inbetween, here is a recipe:
This is what I use as a dry shampoo.
Sprinkle a small amount of mixed powder through the hair and brush for 5 minutes.
1/2 oz. (7 g.) orris-root powder
1/2 oz. (7 g.) arrowroot powder
I have used (and still use) just the arrowroot powder alone and as a body powder as well. It works for me.
I also use a camomile tea as a rinse during the summer, and it will also bring out highlights (shine) to your hair. It is also reported to calm and soothe a dry scalp, but my scalp isn't dry so I can't vouch for this claim.
A simple conditioning treatment is to mash up a whole avocado, massage into the hair and scalp, cover with a plastic bag and leave for an hour before shampooing.
They also say olive oil is good for brittle, dry hair. Warm 2 tablespoons of olive oil, gently massage into every part of the scalp and comb through. Then wrap the head in a steaming towel. Treat for 20 to 30 minutes, reheating the towel if necessary. Shampoo and rinse.
I will also offer you a coconut oil conditioner recipe as I've read that this oil is an excellent moisturizer as well, which I have tried once, but I'm not a big fan of leaving oil on my scalp and hair.
2 tablespoons coconut oil
1 tablespoon cider vinegar
Melt the coconut oil, beat the egg and blend it in and then add the vinegar. Keep warm otherwise the coconut will solidify. Apply to the scalp and head while warm, then cover with a steaming towel.
I have tried many of these conditioning treatments, but I usually use the dry shampoo treatment, so I don't have to wash my hair every day which is why my scalp and hair become somewhat dry (even though I have a tendency towards oily scalp/hair).
I also liked to rinse with flat beer, but lately I never seem to have flat beer lying around.