With heat
When you are trying to grow your hair, it is advisable to use heat as sparingly as possible. If you have to heat style your hair, then rather air dry first.
The best way to air dry hair if you plan to style it with heat, is to comb your hair around your head, this is called wrapping, and then putting a stocking or cling wrap over your hair. Allow to air dry to as dry as possible before using heat.
