How To Build Window Boxes | i should be mopping the floor

How To Build Window Boxes

This Post for Window Boxes is Sponsored by Miracle Gro and Bonnie's. All opinions are mine.

We've been dreaming of building window boxes for years. This little area of our patio was in desperate need of, our existing herb garden is ready to expand. So window box + fresh herbs = the perfect lil' window box herb garden. We're now wanting a hundred more window boxes...they're addicting.

Easy Window Boxes
We have this random window on our patio that actually goes to a store room in our garage. It's kind of a focal point...but into a weird place. I made a little cafe curtain for the window (to mask the storage factor of this room that was very visible) and then realized that maybe a bit more color and fun is what the spot needed. And why not throw a little functionality in, to boot? We've been thinking about window boxes in a few spots for a while, and this quickly became a no-brainer. Plus...we love fresh herbs. This is the perfect spot for a Window Box Herb Garden. See how it came together below.

Easy DIY Window Box

How To Build Window Boxes

Our house is full of long windows...the type that go from the floor to the ceiling. But there are a handful of windows that don't...and they've been crying out for window boxes. Now that we've tackled this one, we feel pretty confident that the other windows are ready to be prettied up, too. And since this one is so close to the kitchen, it was only natural to fill it up with herbs. We have already put this herb garden to use for soups and salads...and it's proving to be delicious

Miracle Gro
We've always used Miracle Gro Potting Mix along with Bonnie Plants when we plant herbs. Remember our DIY Planted Posts? Or our Rolling Planter Box? Both of those planter projects thrived because of Miracle Gro Potting Mix. Miracle Gro was first developed in 1951...they're a brand we can all trust. Their products help grow plants 2-3 times as big as plants without Miracle Gro Potting Mix. I've used their soil and plant food for years...just like my mom always did (and she has the greenest thumb ever).

Bonnie Plants
And we always choose Bonnie Plants. They have the best veggies and herbs and such a great selection. When we were grabbing our herbs for the window box, we happened to run into the Bonnie Plant man and his truck full of deliciousness! He was actually very helpful in our selection process. 

And did you know you can order all of your Bonnie Plants and Miracle Gro products through Walmart's online site? You can even utilize the Pick Up Today feature for your Miracle Gro Potting Mix.

Window Box Construction

Supplies for Window Boxes

Ready to build your Window Box Herb Garden? You'll need a few supplies:
  • 2-1"x10" boards in 8' lengths (treated boards are best, but may not always be available in that size...we used untreated and then coated them later)
  • nails
  • wood glue
  • nails (we also found a nail gun to make quick work of this)
  • medium grit sand paper 
  • outdoor paint/marine grade sealer
  • 3 shelf brackets (check the weight limit before buying...our brackets are designed to hold 70 pounds apiece, or 210 pounds, altogether)
  • masonry anchors or screws (if securing your window boxes into brick)
  • drill or driver (if using masonry screws, you'll need a hammer drill)
  • saw or compound miter saw
  • Miracle Gro Potting Mix
  • Bonnie Herbs

Window Box Supplies

Directions for Building Window Boxes 

We started by cutting three of our 1x10 boards to the length of our window (36"). You'll need to cut your pieces according to your window's measurements. After our three boards were cut, we did a dry fit to determine the length of our two end pieces, and then cut those accordingly.

Nail Gun Uses
We secured the pieces with wood glue and then used our nail gun. We drove a nail about every three inches where we joined the pieces together. 

Window Box Tutorial
Repeat the process on the end pieces, too. 

Finishing Window Boxes
After allowing the wood glue to dry overnight, we filled the nail holes with putty (we had set our nail gun to sink the holes for a seamless finish...if you're doing this by hand, use an awl to drive the nail head below the wood's surface). After the putty dried, we sanded the entire piece for a nice, smooth finish. 

Painting Window Boxes
I painted the box with an outdoor paint and sealed it with a marine grade sealer (since this box will definitely be exposed to the elements). I didn't paint the entire inside of the box, but I did seal the inside thoroughly.

Drilling into Masonry
We attached our brackets to the brick with masonry screws. We predrilled these holes with a hammer drill and masonry bit ahead of time. Again, be sure to watch the weight limits on your brackets (ours hold 70 pounds apiece). This is a new masonry screw system we tried out...we used to use anchors into the mortar. However these new screws are designed to be used in the actual brick. So far, so good!
Once we loaded our window box onto the brackets, we did not screw the brackets into the box...only because I'd like the option of bringing this window box into the sunroom in bad weather. But, you can totally attach yours, if you're more comfortable with that.

Bonnie Plants
We chose our favorite Bonnie herbs for our window box. Once we have a few more window boxes, we plan to have every herb imaginable. This time around, we used Onion Chives, English Thyme, Lemon Thyme, Dill, and Basil. I fell in love with the Lemon Thyme we used in our Sunroom Herb Garden and wanted to have access to even more. It's delicious in two of my favorite soup recipes. And we use chives and dill in our eggs for breakfast. 

Drainage Holes
Before planting, be sure to drill adequate drainage holes in your window boxes. Besides sealing with the marine grade sealer, I didn't use any type of joint sealer within our window box. I wanted there to be plenty of drainage so we didn't run into any issues.

Miracle Gro Potting Mix
I filled up the box with my Miracle Gro Potting Mix and was ready to plant.

Planting Herbs
We may have gone a bit too herb crazy and had to plant a couple in alternate containers until we build more window boxes around the rest of the house. 

Cute Window Box
Once the window box was planted, we slid it onto the brackets.

You can also see how we put this together, in the video below:

Onion Chives
We used a couple of cans left over from our Tin Can Flower Garden for our overflow herbs.

Fresh Chives
And seriously...who doesn't love fresh chopped herbs in the kitchen?

Window Boxes with Herbs
Again, be sure to grab your herbs at Walmart in the Garden Center.

Miracle Gro Single Packets
I don't have a hose or spigot on this side of the patio, so I use my trusty watering can. I was excited to find these little Miracle Gro packets of plant food that are perfect for my watering can. When I was a kid, my mom recycled old milk jugs for her watering. She would put a couple of spoonfuls of Miracle Gro Plant Food in the bottom of each jug and then leave them each under a drippy faucet on our back patio. She would probably have a dozen pre-mixed Miracle Gro Plant Food jugs ready to use. Our yard was so lush and full of flowers that she used every bit of that on a regular basis. 

Herbs for Garden
I can't wait until we have half a dozen window boxes full of herbs. Our laundry room window by the garage is next on the list. 

English Thyme
I wish you could smell how delicious this area is now!

Cute patio ideas
And check out the update below of how much this box has grown in the last month!

Window Box Update
The above photo shows how BIG our herbs our was taken about a month after we planted. We're truly LOVING this project and want a few more window boxes, now!

Looking for More Ideas for Window Boxes?

Patio Window Boxes
Where would you like some herb-filled window boxes?


  1. I love how bright and cheerful that area looks!

  2. I love the window box. It is my favorite color. The hubby and I will be making a larger one for our kitchen window. Thanks for the inspiration!

    1. Thank you so much, Lynnann! Hope you enjoy yours, too!

  3. Arrange the flowers with the tallest in the back and shortest in the front. Depending how deep your box planters are, you may get two or three rows of flowers in. Pack them fairly tight, because you want the look to be overflowing.

    1. That is a great tip, Hannah! Thanks so much for sharing. I'll try that!

  4. Wow, it is such a useful step-by-step guide. Drilling adequate drainage holes is really really important. We will realize the importance after we water too much water then we should we one day. Otherwise we will face a severe drainage problem.

    1. Hi Steven! I'm so glad this guide was useful to you! Yes! Drainage is VERY important! It's not a step that should be missed. Thank you bunches for stopping by! Take care! xoxo