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How to: Make a DIY Modern Planter Box for Under $40

by on Dec 3, 2020

While there are many pre-made planter boxes available, building your own allows you to customize the size, style, and materials. In this post, we’ll show you how to create a sleek and modern planter box using simple materials and tools. This DIY project is perfect for both beginner and experienced builders and can be completed in just a few hours. Follow along with our step-by-step instructions and bring some natural beauty to your outdoor space with your very own handmade planter box.

This year, we decided to take our first baby steps towards a more modern and clean outdoor space. We decided to start with the first thing people will see when they arrive. First up, a sleek and modern outdoor planter for our front patio. This planter box is great for planting seasonal greenery and flowers, plus storing it away for the winter months will be easy-peasy.   

DIY Modern Flower Box


  • Planter (pick up a basic plastic planter that suits your outdoor space)
  • Two eight-foot long 2 x 4s
  • 1 x6 Cedar planks (ours had tongue and groove edges, which was awesome)
  • Crosscut saw: a hand saw, circular saw, or chop saw will work
  • Drill and driver bits
  • Hammer and nails or nailer
  • Optional: Blow torch and scrub brush
  • Optional: Kreg pocket hole jig and 2 1/2″ pocket hole screws

Step 1

DIY Modern Flower Box

The easiest way to begin is by constructing a frame around a store-bought planter. Start by measuring your planter. Ours measured 36 x 8″. 

Step 2

DIY Modern Flower Box

Using your saw, begin cutting your 2x4s according to the proper measurements.  The inside measurements of the frame should be the same as the plastic planter, plus whatever height you prefer. The end measurements for the 2×4 frame were then 36″ x 8″ x 18″. 

Step 3

DIY Modern Flower Box

Using a Kreg pocket hole jig, create holes in each of your 2x4s. If you don’t have a jig, consider investing in one for this project. They’re awesome! If not, you can just screw through the side grain with 3 1/2″ long screws. (You can flip the bottom and top pieces to fit).

Step 4

DIY Modern Flower Box

With your 2 1/2″ pocket hole screws, attach your 2×4 frame together accordingly using your drill.  

Step 5

DIY Modern Flower Box

Once your frame is assembled, place your plastic planter into the top. It should fit nice and snug. 

Step 6

DIY Modern Flower Box

Onto the exterior of your frame! Take your cedar planks into a safe area (you’ll be using a blow torch for a fun Shou Sugi Ban effect!). Using your blow torch, begin by carefully charring each cedar plank. Use broad, even strokes, just like painting. 

Step 7

DIY Modern planter Box

Once charred, allow the wood to cool down a bit. Using a bucket of water and a scrub brush, clean the excess char (otherwise everything it has contact with will get black and dirty). All that will be left is the toasted wood. 

Step 8

boards for making the planter box

Allow to dry completely. 

Step 9

measuring for the planter box

Once dried, cut the planks according to the measurements of your 2×4 frame. 

Step 10

nailing planter box together

Using a nail gun, attach cedar planks to frame. 

Step 11


Once the the cedar planks are all properly attached, char any edges that have not yet been treated. 

Step 12

finishing the box with natural oil

Clean with a wet cloth. Optional: Finish with a natural oil. 

Step 13

assembling the planter box

Once complete, simply place plastic planter back inside your new wood planter! (The finished frame should measure 38″ x 11 1/2″ x 18″)

Step 14

adding garden soil

Pour in your soil. 

Step 15

adding plants

Feel free to plant whatever your heart desires. We wanted a modern look, so we decided to plant Bulbous Oat Grass for a sleek finish. 

finished planter box
finished planter box on the porch

I am in love the simplicity of the overall look and how it instantly modernizes our front entryway. Can’t wait to work on our next outdoor project! 

finished planter box
finished planter box
finished planter box
Square planter box made of dark wood planks and filled with grass-type plants, alongside the wall of a home.

Adding a touch of greenery to your outdoor space can make a big difference in the look and feel of your home. If you’re looking for a simple DIY project to spruce up your porch or patio, a modern flower box may be just what you need. With its clean lines and minimalist design, this DIY modern planter box will add a touch of elegance to any outdoor space. So roll up your sleeves and get ready to create a beautiful home for your favorite plants.

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