
Creating a wood window planter box is a fun and rewarding DIY project that can add a touch of natural beauty to your home. It's also a great way to bring some greenery into your space without taking up too much floor space.
To start, you'll need to choose the right type of wood for your planter box. Western red cedar is a popular choice because it's naturally resistant to rot and insects, and it has a beautiful, rustic look.
Western red cedar is a durable wood that can withstand the elements, making it perfect for a planter box that will be exposed to the outdoors. It's also relatively inexpensive compared to other types of wood.
You'll also need to decide on the size and design of your planter box. Consider the size of your window and the type of plants you want to put in it. A smaller box with a shallow depth is perfect for herbs or succulents, while a larger box with a deeper depth can accommodate larger plants like tomatoes or peppers.
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Planning and Preparation
Measure carefully to decide how long you want your planter to be, as most flower boxes are either the same length as the window or slightly shorter.
Consider the window's height and decide on a suitable length for your planter, keeping in mind that most flower boxes stick out about 25% of the window's height.
Think about how far you want the box to stick out from the wall and mark the board accordingly, then cut along the markings using a miter saw.
Suggestion: Pink Flower Hanging Basket
Gather Tools
To gather the tools you'll need to build your window box, start by gathering the basics. A miter saw, drill driver, quick flip drive, and measuring tape are all essential tools to have on hand. You'll also need a 1/4 inch drill bit to make any necessary holes.
If you're planning to use a drill to install your planter into the side of your house, you'll need to gather additional tools. These include a manual staple gun and staples. On the other hand, if you're planning to hang your planter without a drill, you'll still need to use a drill to attach the hangers to the box.
Here's a list of the tools you'll need to build a planter box:
- Miter saw
- Drill driver
- Quick flip drive
- Measuring tape
- 1/4 inch drill bit
- Manual staple gun
- Staples
Measure and Mark
To get your planter centered with the window frame, measure the length of the box and window. Measure the length of the box and window to figure out how to center the planter with the window frame.
Hold the box slightly away from the wall in the center of the window while the other marks 2-3 spots on the wall where you'll need to drill. Have one person hold the box slightly away from the wall in the center of the window while the other marks 2-3 spots on the wall where you'll need to drill.
Make sure the marks are evenly spaced out to distribute the weight of the box. Evenly spaced marks will ensure the weight of the box is evenly distributed.
If the outside of your home has siding, you may need to remove a few strips to locate the studs in your wall. Use a stud finder to locate the studs.
If you are drilling into brick, you do not need to drill into a specific area of your wall.
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Building the Frame
To build the frame of your wood window planter box, start by assembling the long box shape using three pieces of wood. Attach the side boards to the bottom board using wood screws and a bead of glue, making sure to drill pilot holes to prevent the wood from splitting.
Clamps can be super helpful in keeping the pieces in place, especially when working with a DIY project like this. Attaching the short end boards to the long pieces can be a bit tricky, so try attaching one of the shorter pieces to one of the longer pieces first, and then use a little bit of pressure to line up the edges.
Using a miter saw, cut the bottom board to the desired length, and then measure and cut two planks of the same length for the front and back of the box. The height of the box should be about 25% of the height of the window, and the side planks should fit neatly between the front and back boards.
Building
To build the frame of your window box, you'll need to assemble the three pieces of wood to form the long box shape. This can be done using wood screws and a bead of glue, and drilling pilot holes to prevent the wood from splitting.
Using a miter saw, cut the bottom, back, and front of the window box to the desired length. For most flower boxes, this is the same length as the window or slightly shorter.
Measure and mark your wood carefully to ensure accurate cuts. It's also a good idea to use a stud finder to locate the studs in your wall, especially if you have siding.
Drilling pilot holes is essential to prevent the wood from splitting, and a quick flip drive can come in handy for this task. Clamps are also helpful in keeping the wood in place while you work.
To attach the short end boards to the long pieces of the box, use a little bit of pressure to line up the edges. This will help ensure the window boxes are square.
If you're attaching the window boxes to your home's exterior, use heavy-duty lag bolts to secure them. This is especially important since the planters can get heavy once they're filled with soil, plants, and water.
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Drill Drainage Holes
To drill drainage holes, you'll want to use a drill bit - a 1/4″ drill bit works well, as seen in Example 2. Drill holes about every 4-5″ apart in a zig-zag pattern to ensure proper drainage.
Drilling holes in a zig-zag pattern allows excess water to escape, keeping your plants happy and healthy. If you're drilling into wood, you can also use a 3/8 bit, as mentioned in Example 3.
For longer-lasting wood window boxes, consider lining them with heavy-duty plastic or box liners to prevent drying out.
Adding Panels and Supports
As you build your wood window planter box, it's essential to add panels and supports to give it stability and structure. You'll need to attach 2 pieces of 3/4″ square to the inside of the face boards, vertically and evenly staggered.
These interior supports will tie in the face pieces and add additional structure to your box. Replicate this process by attaching 2 pieces of 3/4″ square to the inside of the back board.
Next, you'll attach the top front panel and both side panels using wood glue and fasteners.
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Add Panels

To add structure and stability to your wood window box, you'll need to attach interior supports. Attach 2 pieces of 3/4″ square to the inside of the first face board using glue and fasteners, vertically and evenly staggered.
This will tie in the 2 face pieces nicely. Replicate this step by attaching 2 pieces of 3/4″ square to the inside of the back board.
The next step is to add the side panels and top front panel. Attach the top front panel and both side panels using wood glue and fasteners.
Explore further: Cedar Planter Box Square
Attach Back Board
Attach the lower back board to the bottom using glue and fasteners.
To ensure a sturdy attachment, make sure to follow the instructions for attaching the back board.
Proper Drainage
Proper drainage is crucial for the health of your plants, as they don't want to sit in a puddle of water.
Drill drainage holes in the bottom of your window box, about every 4-5 inches apart in a zig-zag pattern, to allow excess water to escape. Using a 1/4" drill bit is a good size for this task.
Drilling 3-4 holes for drainage will prevent waterlogged soil and root rot. A 3/8" bit is also a suitable size for this purpose.
Lining your wood window box with heavy-duty plastic or box liners can help with drainage and prevent the wood from drying out too quickly.
Finishing Touches
To add a decorative touch, consider adding a trellis or obelisk to your wood window planter box. This will not only enhance the aesthetic appeal but also provide support for climbing plants.
You can choose from a variety of materials, such as metal, wood, or plastic, depending on your personal preference and the style of your home. Just make sure it's sturdy enough to hold the weight of the plants.
A layer of mulch or decorative stones at the bottom of the planter box will help retain moisture and suppress weeds. This will also give your plants a beautiful base to grow from.
Remember to add a drainage system, such as a layer of small rocks or a drainage pipe, to prevent waterlogged soil and root rot. This is especially important for plants that prefer well-draining soil.
Worth a look: Drought Tolerant Window Box Plants
Installation and Hanging
To install your cedar wood window box planters, you can use L brackets or corner angles and lag bolts.
You can also add corbels for support like Morgan and Jamie showed here.
The most expensive piece of equipment for this project is a miter saw, which ranges from $90-$200.
To hang your window box, you'll want to attach it to the wall securely, but you can cut costs by renting equipment from a home improvement store or buying second-hand tools.
The grand total for your project should cost no more than $370, depending on the tools you already have.
If you just need to purchase the wood and hardware, your final price should range between $160-$310.
DIY and Cost Considerations
Building a wood window planter box is a fun and rewarding DIY project.
You'll need to head to a box lumber store, such as Home Depot or Lowes, to purchase the necessary materials.
The supplies and tools you'll need to build a 6' x 6.5" x 5.5" window box include cedar boards, screws/fasteners, interior brackets, and 2 L brackets to hang the box.
A fresh viewpoint: Window Box Brackets Wood
The estimated cost to build one cedar window box is $25, depending on your local lumber prices, and this does not include the stain.
You'll also need a compound miter saw, a drill with bit, and a hammer to complete the project.
The total cost of your project will vary depending on the tools you already have, but it's estimated to be no more than $370.
You can cut costs by renting equipment from a home improvement store, buying them second hand, or borrowing them from a friend.
Here's a breakdown of the estimated costs for the project:
Design and Customization
A wood window planter box can be designed to fit any style or decor. You can choose from various types of wood, such as cedar or pine, which are naturally resistant to rot and insects.
The size of your planter box will depend on the size of your window and the amount of space you have available. A typical size is around 6-8 inches deep and 12-18 inches wide.
To customize your planter box, you can add a trellis or a lattice top to provide support for climbing plants. This is a great way to add some extra visual interest to your window.
Dreams

Dreams can be a powerful motivator for DIY projects. We've all been there, envisioning a perfect outcome for our homes, but sometimes life gets in the way.
Some projects, like adding a wooden window box to each double front window, can take years to plan. In this case, 25 years is a bit of an exaggeration, but it's a great example of how long it can take to bring a dream to life.
Having a clear vision of what you want is essential for making progress on a DIY project. In this case, the author had a strong desire to add curb appeal to their home with window planter boxes.
Using your imagination and creativity can help you find solutions to budget constraints. The author and their hubby were serious DIYers who didn't want to spend money on ready-made window flower boxes.
Building a Custom Solution
Building a custom solution for your window planter box can be a cost-effective and fulfilling experience. You can use scrap wood pieces, like the ones the author had left over from other projects, to save money.

The author's husband wanted to use cedar boards, but they didn't have any on hand. Cutting off the dog ear section of the cedar wood boards is a good option if you want to use cedar but don't need the fence detail.
Having a clear plan and budget in mind can help you make decisions about materials and design. The author had 25 years to plan their project, but it's never too late to start.
Using cedar boards can add a nice touch to your window planter box, but it may require some extra planning and preparation.
Instructions and Steps
To build a wood window planter box, start by selecting a suitable wood type, such as cedar or pine, which can withstand outdoor weather conditions.
Cut the wood into the required pieces, including the box's sides, bottom, and back, according to the dimensions specified in the design plans.
Arrange Boxes
To arrange boxes, start by aligning them with the marks on the wall. This will help you achieve a balanced and symmetrical look.
Make sure the boxes are centered when transferring the marks onto them, just like with window boxes.
How to Make a Planter in 4 Steps
To make a planter, you'll need some basic materials, like a container, soil, and plants.
Gather a container that suits your needs, such as a wooden box or a plastic tub.
Choose a location with good drainage and sunlight for your planter.
In 4 simple steps, you can create a beautiful planter that will bring life to any room.
Materials and Supplies
To build a wood window planter box, you'll need a variety of supplies and tools.
Here's a breakdown of the materials you'll need:
- 3 1/2 – 6′ long cedar dog ear fence boards (5.5″ wide)
- 2 – 4′ x 4′ outdoor posts (we used 6′ long posts)
- 1 1/4″ wood screws for outdoor use
- L-brackets (optional for additional security)
- clamps
- wood glue
- 1 bag Sakrete
- outdoor stain (we used Valspar exterior stain and sealer in Black)
- various plants
- Plant-Tone All-Purpose Plant Food
- container soil
- large contractor-grade trash bags
- manual staple gun and staples
- 1/4 inch drill bit
- measuring tape
- drill driver
- quick flip drive
- miter saw (or a hand saw, or circular saw)
Cedar Materials:
Cedar wood is the recommended choice for your DIY window planter box due to its high resistance to water and ability to withstand the weight of your plants.
When selecting cedar wood, you'll need six cedar deck boards, which will provide the necessary material for the box's frame and bottom.
For additional support, a 4′ piece of 3/4″ inch cedar square is required.
You'll also need wood glue to secure the pieces together.
To assemble the box, you'll need small galvanized corner brackets with screws, galvanized finishing nails, and 1 3/4″ deck screws.
For mounting the box, galvanized L brackets are a must-have.
To line the interior of the box, heavy weight plastic is recommended.
Optional materials include stain or paint and wood filler to finish your box.
Supplies and Tools
To start building your window box, you'll need to gather some essential supplies and tools. You'll need 3 1/2 – 6′ long cedar dog ear fence boards, which are about 5.5″ wide.
For the installation process, you'll want to have a variety of tools on hand. A miter saw, drill driver, quick flip drive, and measuring tape will come in handy for cutting and assembling the wood.
You'll also need some basic fasteners like 1 1/4″ wood screws for outdoor use. These will be used to secure the boards together.
If you want to add an extra layer of security, you can use L-brackets. These can be attached to the box and the wall for added stability.
For the actual building of the box, you'll need some wood glue and clamps to hold the boards in place.
To anchor the box to the wall, you'll need two 4′ x 4′ outdoor posts. These will be used to support the weight of the box and its contents.
You'll also need some Sakrete to set the posts in place. This will ensure a stable foundation for your window box.
To finish the box, you'll want to apply some outdoor stain, such as Valspar exterior stain and sealer in Black. This will protect the wood from the elements and give it a nice finish.
Here's a list of the tools and materials you'll need:
- 3 1/2 – 6′ long cedar dog ear fence boards
- 1 1/4″ wood screws for outdoor use
- L-brackets (optional)
- Miter saw
- Drill driver
- Quick flip drive
- Measuring tape
- 1/4 inch drill bit
- Wood glue
- Clamps
- 2 – 4′ x 4′ outdoor posts
- Sakrete
- Outdoor stain (e.g. Valspar exterior stain and sealer)
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