23 Steps On How To Build Cedar Planter Boxes

Here’s The Easy Way On How To Build Cedar Planter Boxes At Home

This latest addition to our backyard has to be my favorite yet. As many of you know when we got our driveway re-poured earlier this summer we ran into the problem that the pervious owners built the patio over the top of the driveway. So you guessed it…as we pulled out the blacktop the patio came with it. Michael came up with a great solution to our problem. Instead of trying to fix a patio in dismay, that we have absolutely no love for, why not build something in its place that we will love?!? Talk about a brilliant idea, no wonder why I love this man.

What I think I love most about this project is you can complete the whole thing in a weekend or even with a couple of hours over a few nights. Plus the impact it makes on your outdoor space and the clean lines are too good not to stare and admire. The cedar tongue and grove is easy to work with and can be found at most hardware or lumber stores. And having a planter prevents any soil and mulch from getting all over the place! We built our cedar planter large enough to plant hydrangeas inside them!

So let’s get down to the nitty gritty.

Supplies you will need:

Cedar tongue and grove (quantity and size depends on your layout)
Treated 4×4 or 6×6 posts
Spare 2×4 or whatever long length, strong wood you have laying around
Concrete mix
Small rocks
Galvanized Exterior nails
Nail gun (I use a Paslode)
Air compressor
Air hose
Tape measure
Compound Miter Saw
Table saw
Hammer
Shovel
Wheel barrel
Plants/flowers
Dirt and mulch

Step by step guide to make your own planter box:

First, clear the area of all plants, leaves and debris.
Measure your space to ensure you purchase enough cedar to build your box and the right amount of posts to secure that box. Note: you will want to build the box higher than the height of 1 piece of cedar (ours is 20 inches).
Mark post holes.
Begin digging each post hole. You will want to dig down at least 16 inches – you could go deeper, but this is a planter box, not a fence. I find that 16 inches is plenty deep and allows concrete to penetrate and hold.
Once each of your holes are dug, measure each of your posts right on prepare for cuts. Remember, you mark the 16 inches and THEN the height of the box itself…don’t cut yourself short!
Begin cutting posts.
Insert the first post. I like to cut small pieces of cedar to ensure I leave the perfect amount of space between the post and concrete so the full piece slides right in once posts are secure.
Insert the second post using the directions in step 7.
Once 2 posts are inserted, use your level to get everything plumb. Then take your 2×4 or spare wood and connect the 2 posts together. This step just adds support prior to adding concrete to each hole.
Repeat steps for all posts.
Once all posts are secure, triple check that they are level. Then open your bog of concrete and pour some dry mix in the hole and add water. Feel free to pre-mix concrete and water in a bucket, this is just the way I do it when working outdoors.
Allow posts to settle in. You may want to wait 24 hours…I started the next steps right away.
Remove your supporting wood pieces.
Measure your first side. I go from one side to the end of the post and cut a 45 degree cut at that mark. All of my corners are 45 degrees.
Take your nail gun (connected to air compressor, if applicable) and secure cedar to posts.
Repeat for all sides.
Repeat for the 2nd and 3rd rows (and if you add more, them too).
I added a cap/ledge across the top of the box to finish it. And it made a WORLD of difference. To do this, take your table saw and measure the depth of the tongue and groove on each side respectively. Set your mark and rip those sides off. Make sure to do this for enough pieces,
Measure your tops, cut the 45’s and secure.
Now your box is built and it is time to level out with dirt.
Add plants/flowers.
Add mulch.
Enjoy!