These Simple Planter Boxes are Easy to Build | The Family Handyman
Costway 28 in. Rectangular Wood Flower Planter Box Garden Yard Decorative Window Box J9D34-A31 - The Home Depot
Amazon.com : 10Pcs Plastic Window Boxes Planters, Black Rectangle Flower Boxes, 16.6 x 6.7 x 5.5 inch Window Planter Boxes Outdoor with Drainage Holes and Trays, Sill Planter Box for Sill, Garden,
17 Planter Box Plans You Can DIY This Weekend - Bob Vila