Note: I am not a professional and do not claim to be an expert. Please be sure to always read instructions for all tools and products. Safety is very important and should be your top priority. Wear necessary protection when using tools (eye wear, hearing protection, gloves, etc.) and dust masks when sanding or cutting. Sarah Flips It is not responsible for any injury or damage. All of my designs are not professionally designed and are for private use only.

Transform your home’s exterior with easy DIY window flower boxes made from cedar fence posts! Discover how this simple and cost-effective project can instantly elevate your curb appeal.

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Are you guys even ready to add instant charm and character to your home’s exterior? Window flower boxes for the win. Here’s the best part: we’re keeping it simple and budget-friendly by using cedar fence posts as our main material. With just a few easy steps, you can create beautiful window flower boxes that’ll make your neighbors green with envy. Lol get it? 

We’ve absolutely loved having these on our house during the warmer months! It’s amazing how such a simple addition can completely transform the look and feel of your home’s exterior. With just a few cedar fence posts and some time, you can create a welcoming and picturesque scene that’ll make you smile every time you come home!

Now, you might be thinking, “But I’m not exactly a master carpenter – can I really tackle this project?” Absolutely! That’s the beauty of using cedar fence posts – they’re affordable, easy to work with, and require minimal woodworking skills. Whether you’re a seasoned DIY pro or a total newbie, you’ll find this project to be a breeze. Plus, the satisfaction of seeing your handiwork brighten up your home’s facade is priceless. With a little TLC and some strategic plant choices, you can create a mini garden oasis that’s as beautiful as it is functional.

Supplies for DIY window Flower boxes

Tools:

Lumber:

  • Cedar fence posts (or alternative material for the boxes)

Materials:

How to Build your own DIY flower boxes

1. Measure

Measure the width of your windows and determine the desired length and depth of your flower boxes. I think it’s easiest to sketch out how you want it to look, so that’s what I did. I ended up making my boxes a little wider than my windows, but I’ve seen them smaller too!

2. sand down your cedar planks

Before assembling everything, sand down your cedar planks. Because this wood is cheap, it’s pretty raw. You’ll want to start with an 80 grit sandpaper and then 120. I used an orbital sander, but a planer would have been a ton faster!

3. Cut cedar fence posts

Cut cedar fence posts to the appropriate lengths using a miter saw. I decided to make my boxes 2 planks high, so I glued two cedar planks together on the long side, and clamped them together with bar clamps. 

Assemble the cedar pieces into rectangular frames, using wood glue and outdoor screws.

I decided to add a few pieces of cedar planks that I ripped to 1.5” wide to add decorative molding to the planters. I added one piece along the top and bottom, and 4 vertical pieces along each side and installed them using a brad nail gun. 

4. stain wood

If you are going to stain or paint your boxes, do that now. I decided to stain mine. A trick I used was adding mineral spirits to my stain to tone down how dark the stain would turn out. It worked great! 

Whether you paint, stain or leave your wood as is, you’ll want to seal the wood with a heavy duty sealer. You can also find a stain & sealant in one. I just did a walnut stain on my garden boxes and loved the deep brown color.

5. drill drainage holes

Using a ⅞” Spade bit, drill drainage holes in the bottom of each flower box to prevent waterlogging.

Line the boxes with landscape fabric or heavy-duty plastic to keep soil in while allowing excess water to drain. I attached my plastic to the boxes with staples. You’ll want to poke holes in the plastic where the drainage holes are. Don’t forget!

6. Attach your L-Brackets to the side of your house

Determine where you need your holes to go into the siding of your house. Drill a pilot hole, then insert your wall anchors. Attach your L-Brackets to the side of your house with large construction screws. This will support the weight of your planter boxes.

7. Fill the boxes with potting soil

Fill the boxes with potting soil and plant your favorite flowers, herbs, or greenery. I added a layer of used Diet Coke cans (a great way to recycle, I guess!), so I needed less potting soil to fill the boxes, which helped them become a little lighter. Water the plants regularly and enjoy the beauty of your new window flower boxes!

8. Attach the boxes to the exterior of your windows using screws

Attach the boxes to the exterior of your windows using screws into the L-Brackets.

Tips and Tricks

  • Install L brackets, but plant your boxes on the ground and then lift them onto the L brackets
  • Buy a 2-in-1 stain & sealant to save time!
  • Consider painting or staining the flower boxes to match your home’s exterior.
  • Select plants that thrive in your climate and receive the appropriate amount of sunlight.
  • Group together plants with similar watering needs to simplify maintenance.
  • Incorporate trailing plants or vines for added visual interest and dimension.

What are the best materials for DIY window flower boxes?

When it comes to DIY window flower boxes, opting for durable and weather-resistant materials is key to ensuring longevity and functionality. Cedar fence posts are often touted as one of the best materials for this project due to their natural resistance to rot, insects, and moisture. Their sturdy yet lightweight nature makes them easy to work with, while their attractive grain adds rustic charm to any home exterior. Additionally, cedar’s natural oils help preserve the wood over time, making it an ideal choice for outdoor projects. Alternatively, other suitable materials include redwood, pressure-treated lumber, and composite materials designed to withstand outdoor conditions. Whatever material you choose, prioritize durability, aesthetics, and ease of maintenance to create window flower boxes that enhance your home’s curb appeal for years to come.

What types of flowers are best suited for window flower boxes?

When selecting flowers for window flower boxes, it’s essential to consider factors such as sunlight exposure, climate, and box size. Opt for flowers that thrive in your specific growing conditions and can withstand the amount of sunlight your windows receive. Some popular choices for window flower boxes include petunias, geraniums, lobelia, begonias, and marigolds, which are known for their colorful blooms and ability to cascade over the edges of the boxes, creating a lush and vibrant display. Additionally, consider incorporating trailing plants like ivy or trailing verbena to add dimension and visual interest to your arrangements. Remember to choose flowers with similar watering and maintenance requirements to simplify care and keep your window boxes looking beautiful throughout the season.