Ash is too placid and down-to-earth (for all his out-there beliefs) to really be a good Gryffindor. He's brave and giving, but not exactly adventurous.
Ravenclaws love to learn and so does Ash, but he's more concerned with emotions and actions than pure thought.
And that's why Ash is a Hufflepuff. Serving others is what he believes he was put on this earth to do, no matter what that ends up looking like. He'll plant a seed, grow a tree, chop it down, and use it to build a house if he has to. His calm dedication is one of his chief qualities, aside from his innocence.
The Scarf of Sexual Preference says: Easy Pickings