Making a window box is a good do-it-yourself project that can be a good project for woodworking enthusiasts. Choosing the right wood is critical for window boxes, because water will be in direct contact with your box and you want it to last. Cedar and cypruss have great reputations as rot resistant choices and will increase your odds of a long lasting window box. The first step is measuring your window to determine the desired length. Next, you will need to build it and lastly hang it. For simplicity, let's focus our attention on the building step only and what skills and tools are required. For this project you should have in your arsenal a drill, a few special drill bits, a brad nailer, and an electric miter saw.



To keep things simple, let's focus on building a 36" long window box and let's use 3/4" thick cypruss wood. Cypruss wood stock can be attained from most local lumberyards in a variety of dimensions. For window box purposes, a 1" x 8" board is recommended. For this box we will need roughly 12 feet of length. Now, miter the board at 34.5" three consecutive times such that you have three boards, one for the bottom, front, and back. We want to join these three boards with screws so that the boards are held tightly together. Place two boards up against each other at ninety degree angle and use wood glue between them. You want to make sure you use a wood glue designed for exterior purposes. Once glued, shoot a few brad nails along the joint to hold the two boards together temporarily. Next, countersink three small holes through the boards in preparation to pass screws in to more securely join the boards in a ninety degree fashion. A countersink drill bit is one that drills a pilot hole deep and a big hole shallow so that the screw head can sink pass the face of the board. Drill three countersunk holes: one on each end and one in the center. Next, sink a screw into the boards so that they grab tightly. The butt joint should show on the bottom of the box. Repeat the same steps to fasten the back board to the bottom boards. When you've finished that, the only thing remaining will be pieces for the side ends.

For fastening of the side pieces I recommend again using gorilla glue and brad nails to quickly secure the piece to the box. Next, countersink some holes and then screws to joing the side pieces. The side piece should be cut to size first. Once the side pieces are attached, the structural assembly of the box is complete. Next, use a drill with a 1/4" drill bit to drill drain holes in the bottom. I recommend placing a hole in each corner of the box and one in the very center where water will likely migrate to the most. Next, caulk inside the box to seal all the inner joints. This will reinforce the box and also keep water from seeping through. Lastly, staple an erosion tarp to the inside of the box. The will filter out water and keep dirt in. That's it, you are now ready to install it and place flowers inside. It's just that easy. If you're not up for the challenge of building a wooden window box every five years, a good idea may be to consider investing in a PVC window box. They're moisture resistant, reasonably priced, and because they don't rot they're designed to last 30 years and more without any maintenance.