Window boxes come in a variety of materials. Here are some choices.
Cons: Heavy, requires paint or stain, and can rot unless lined.
Shown: Paneled window box from Walpole Woodworkers, $135 with two brackets.
Pros: Inexpensive, lightweight.
Cons: Cracks easily, looks cheap.
Shown: Generic plastic box, $10
Pros: Appropriate for Mediterranean-style houses.
Cons: Heavy; needs cage to support it; will crack apart if not brought in during a freeze.
Shown: Roman window box from Marshall Pottery, $17.
Pros: Elegant profile; will develop patina.
Cons: Will dent and can heat up in direct sun.
Shown: Bronzed window box from Smith & Hawken, $55.
Pros: Extremely durable and lightweight alternative to wood.
Cons: Very expensive.
Shown: Fiberglass window box from Smith & Hawken, $195.