For dandruff and dry scalp you can use coconut oil, olive oil or almond oil therapy once or twice a week or whenever your scalp feels itchy.
1.Take a little oil (any one oil could be enough but if available mix them all ) in a bowl.
2.Warm it then
3.Massage it in your scalp.
4.keep it for atleast one hour ( if you can keep it for long then its well and good )
5.Give steam to hair roots by wrapping a hot towel around your head ( for 5 mins or more ), so that oil will get penetrated deep into the roots.
6.After this you can wash your hair with any mild shampoo.
I am sure this works for you as well.