Preheat the oven to 325 degrees F. Line two large baking sheets with parchment paper.
In a large bowl, combine oatmeal, wheat germ, oat bran, almonds, pecans and walnuts in a large bowl.
In a saucepan, stir together brown sugar, maple syrup, honey, oil, cinnamon, salt and vanilla. Bring to a boil over medium heat, then pour over the dry ingredients, and stir to coat. Spread the mixture out evenly onto the baking sheets.
Bake in the preheated oven until crispy and toasted, about 20 minutes, stirring once halfway through. Cool.
Store in airtight containers.