I'm interested in planting a heather bed alongside the south side of my house next spring. I'd like to prep the soil this fall. Currently there is a minor drainage issue in the area where rainwater runs into the bed but that is a top priority to have fixed with a new driveway next spring. What else do I need to do to make it ready? I know it needs peat and sandy soil. How do I go about putting it all together and in what proportions?

Thanks.