These DIY window boxes are a great way to add year-round curb appeal to your house. I decided to design and build my own after I was unable to find premade window boxes that I loved. The main issue I had with premade window boxes is that most of them are way too small. I wanted mine to look more substantial and proportional to the size of the windows. I also wanted the front of the window boxes to be slightly angled to create a more custom look. I’m so glad I decided to make my own because I love how they turned out!
During the summer, window boxes look beautiful filled with flowers and vines, or even ornamental grasses. There are so many choices at the nursery in the spring that it can be hard to decide! Last year I went with cascading pink petunias that looked great all summer long. Window boxes can also look great during the winter. I like to fill mine with mixed evergreen branches and strings of solar lights. (Thanks for letting me chop branches off your trees mom!)
For durability, I chose to use pressure-treated wood. Because of the chemicals used to treat the wood, these window boxes are not suitable for edible plants or herbs. To avoid this issue you can use rot-resistant cedar wood, although it’s a lot more expensive.
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Building the Window Boxes
The finished window box pictured here is 52” long. I decided to make the window box extend 2” longer than the window on each side. The boards I used included two 1”x4” pressure treated boards (10’ length each), and one 1”x6” (6’ length). I cut all the boards to 52” length. This created four 1”x4” boards that are 52” and one 1”x6” board that was also 52” in length. I also used small 1”x2” pieces to use as braces inside of the window box. This adds extra strength and also prevents the boards from warping.
Using a table saw, my dad cut the edges of the front boards with the blade tilted 15°. In the picture below I’ve marked which boards you need to cut on an angle to create this look.
After all the pieces were cut, I assembled the window box with exterior wood screws. First, I attached the two front pieces together using the 1”x2” braces. To create the braces, I used four 4” lengths of 1”x2” spaced evenly along the back of these boards. I attached each brace with a little bit of exterior wood glue as well as screws. I repeated the same process for the back of the window box. Make sure your screws are short enough that they don’t go through the front of your window box). Then I assembled the back, bottom and front of the window box together using exterior wood screws. I think I may have used 1-½” or 2” screws.
To create the side/end of the window box, I used the remaining 20” piece of the 1”x6” board. I used my miter saw with the blade rotated 15° to cut this piece in half on an angle to create the two end pieces. Then I measured the distance across the bottom of the end of the window box (see yellow line in the side view picture above), and cut the 90° angle of each board to the proper size. I then attached the end boards with exterior wood screws through the front, back and bottom of the window box.
Lastly, I drilled 4 drainage holes in the bottom of the window box using a large drill bit.
Staining the Window Boxes
After the window boxes were completely assembled, I stained them using an exterior one-step stain/sealer. I used Olympic Elite Woodland Oil in Mountain Cedar. I also used this stain/sealer on a pergola that is fully exposed to the elements and the color has held up extremely well over the past three years.
Attaching the Window Boxes to the House
To attach these DIY window boxes to the brick wall, my dad used a hammer drill with a masonry drill bit. Then, we used Tapcon Concrete Anchors (¼” x 2-¾”) to attach the brackets for window boxes to the house. The packaging will tell you exactly which masonry drill bit you will need (or it might actually be included).
First, we attached two metal L-shaped brackets to the house (make sure they’re level!). Then we set the window box on the brackets and attached the underside of the window box to the bottom of the bracket. For extra support, we also attached a couple more tapcon screws (with washers) through the back of the window box directly to the house.
We used washers because we were concerned about the weight of the filled window boxes creating too much pressure on the screw heads attaching the back of the window boxes to the house. The large washers help to distribute the weight/force over a much larger area.
What do you think of these DIY window boxes? Do you have any favorite plants for window boxes? Leave a comment below!