A good quality potting mix, then add 25-50% perlite to it.

If I use a high quality mix like Fafard, Happy Frog or Forestfarm I don't add anything. If I'm using a lesser quality mix I add perlite, Turface, coir croutons, Hydroton, crushed granite or some other material to improve drainage and some leaf mold or compost to add nutrients.

Thanks for info,season is short so i want all the help i can get to grow the max. out of plants