Lightly spray a 10-inch cast-iron skillet with cooking spray.
On a lightly floured surface, unroll piecrusts. Lightly brush water onto 1 crust. Top with remaining piecrust. Roll out crusts to a 14-inch circle. Transfer crust to prepared skillet, pressing into bottom and up sides. Fold edges under, and crimp as desired. Freeze until crust is firm, about 30 minutes.
Meanwhile, in a large bowl, gently stir together all berries, granulated sugar, tapioca flour, 2 teaspoons ginger, and orange zest and juice. Let stand for 30 minutes.
In a medium bowl, whisk together all-purpose flour, brown sugar, salt, and remaining ½ teaspoon ginger. Using your fingers, work butter into flour mixture until large crumbs are formed; stir in pecans. Refrigerate mixture for 10 minutes.
Preheat oven to 375°.
Stir fruit mixture; pour into prepared cold crust. Sprinkle pecan mixture all over fruit.
Bake until crust and topping are golden brown and filling is bubbly, about 1 hour, covering with foil to prevent excess browning if needed. Let cool completely on a wire rack before serving.
Recipe by Southern Cast Iron at https://southerncastiron.com/mixed-berry-crumb-pie/