Houseplants are happiest when they're next to a window. This movable window box is a handsome home for potted plants. It's sized to hold a pair of off-the-shelf plastic boxes to prevent water from leaking out and damaging floors or rugs.
The window box is built from a half sheet of plywood and is trimmed with lengths of 1-by-3 and pieces of thin molding. Furniture castors mounted to the base make it easy to move the unit. Materials are available at home stores.