Okay, so step one is deciding what you want your flower boxes to look like. There are plenty of ready made options available at Home Depot and Lowe's, and you can find even more ready-mades online. However, it was important to me that the flower boxes didn't look like they were stuck on as an afterthought. I wanted them to complement the existing architecture of the home, and I wanted them to look like they were part of the original elevation plan and had always been there. I wanted them to look custom. So we went for a drive through a few of the high-end custom home neighborhoods nearby so I could develop ideas about what styles worked well with architecture similar to our home. I decided that our traditional brick home should have "wood" flower boxes with decorative bracket supports, and that we should paint them to match the trim paint on the house. Another thing I noticed on this window box drive-by was how few of them actually had flowers in them. A couple of flower boxes actually had tacky faded silk flowers stuck into them -- yuck! Discussing this, we decided that non-gardening, dual-income homeowners were having trouble keeping plants alive in the flower boxes, since they would need to be watered daily throughout the summer. My husband began brainstorming about irrigation, while I worried about ugly hoses going up the front of the house. One more thing I observed from the custom builder flower boxes was the width of the flower boxes. Unlike the little ready made flower boxes, the custom home ones always extended the full width of the windows, and if there were shutters, the window box extended approximately 1/3-1/2 of the width of each shutter.
plasticky, low maintenance "PVC wood." I was concerned about this initially, but then he showed me that our window trim and shutters are all made of the same stuff and reassured me that, once the flower boxes had been painted, they were going to look just like wood. The PVC boards can be cut with regular woodworking tools, are paintable, and come stamped with a wood grain that looks pretty fake up close. I was skeptical, but he was right -- they look great now that they are painted and installed and, unlike real wood, they are termite proof, low maintenance, and guaranteed to remain rot-free. You can get this stuff at your local Home Depot or Lowe's.
Bernie's next concern with the window boxes was making sure that the bottoms could support the weight of all that wet dirt without falling out. Using a dado blade on his table saw, he routed a channel 1/2" up from the bottom of each of the side boards to accommodate the thickness of the bottom board and lock the bottom in place. The boxes were assembled using 2 1/2" finish nails and PL Premium Polyurethane Construction Adhesive. I had him attach some simple trim pieces to the top and bottom of each box. I was tempted to go with something more interesting, but the trim work on my house is very plain and it was very important to me that the window boxes would not stand out as an obvious addition. If my home had more of a country French or Mediterranean facade, I would have designed completely different flower boxes and ordered some custom Tableaux faux wrought iron pieces to overlay on the window boxes. Maybe the next house!
The next step was drainage. Bernie drilled drainage holes spaced 12" apart, using a 5/8" drill bit. To prevent soil falling out through the drainage holes, he glued 2" squares of fiberglass screening over each hole on the inside of each flower box. The only thing missing at this point was the decorative brackets I wanted, but I wasn't able to find anything I liked at Home Depot or Lowe's so I turned to one of my trade resources, Outwater Plastics. I'm not sure if they sell direct to consumers, but if not, they should be able to direct you to a retail source for their products. Outwater has lots of choices of decorative PVC, and they are also a great source for hardwood appliques and corbels, decorative glass, and other products that I use for mini-face lifts in kitchens and baths when clients are looking for an update but aren't ready to remodel. The brackets I selected for my window boxes were backordered a couple of weeks, so Bernie went ahead with painting and installing the boxes while we waited for the brackets to come in.
Masonry bits were used to drill into the brick to mount 5" L-brackets with a white outdoor coating to the house beneath each window. I am not happy with the way these L-brackets are visible from the bottom of the window boxes, but the window boxes themselves are also glued to the brick as well as anchored with 3" carriage bolts, so Bernie has promised to cut off the visible part of those ugly L-brackets now that the construction adhesive has had time to fully cure.
Now, you may be wondering about that little clear hose that is sneaking along the mortar line to the left of this window box. Remember all those empty flower boxes I saw at the country club, and even worse, the ones with fake flowers stuck in the dirt? We didn't want to have to schlep a watering can around inside the house every day to water our flower boxes through the windows, and we didn't want our flowers to die when we travel, so Bernie tapped into our existing sprinkler system, tying the flower boxes into the zone dedicated to the front flower beds. The hose he used is just 1/4" clear propylene tubing from Home Depot, attached to the mortar with clear plastic C-clips and clear silicone. Although you can clearly see the tubing up close, you have to look really hard to see it from the ground and it's invisible from the street. There are five drip irrigation heads in each 7' window box, and three heads in each of the 4' boxes.
Just for kicks, here's a picture of what the front of our house looked like from this angle when we bought it three years ago. I think that's the home inspector with the back to his camera, so we hadn't even closed on the property yet. The home was three years old when we bought it and the previous owner hadn't done a thing with landscaping beyond what the builder had originally planted. In addition to neatening the unkempt shrubs, and revitalizing the lawn, we also expanded the depth of the bed to the left of the front door, added additional zones for the flower beds to the existing irrigation system, rearranged a few existing plants and added Stella d'Oro day lilies, the blue perennial ground cover flowers whose name escapes me at the moment, and the little yellow daisies with purply-blue centers. We also repainted the front door a more attractive shade of red and replaced all of the door hardware and house numbers, and replaced the cheapo white hexagonal flush mount fixture over the front door with a pretty hanging lantern style.