DIY Large Wooden Planter

by Sarah
4 Materials
4 Hours
Last post I shared my recent deck refresh. Now I’d love to share with you how I made this DIY large wooden planter to go on our newly updated deck! It is super easy and looks pretty great once it’s finished!
I was hoping to make this large wooden planter out of cedar, but my local stores don’t seem to carry much cedar product. I was bummed, but assured that I could use pressure-treated wood in place of the cedar so I decided to give that a shot.For the horizontal boards on the sides, I purchased four 8 foot long 1×6 pressure treated boards. These boards were all cut to just about 24 inches in length. You will need a total of 16 pieces cut to that size (4 for each side).
AssemblyOnce the side boards are cut, a 2 x 2 pressure-treated board was used to attach them together. This piece was cut to about 22 inches, or just about the height of the 4 horizontal boards. I lined the horizontal boards up together on the ground and put the 2×2 on top of it. This was then screwed into the horizontal boards from the backside using two 2″ spax screws per board.
Because of the way these are attached, the outside horizontal boards will overlap a bit in the corners (butt joint). The easiest way to figure out how to overlap, is to make four separate panels first each with the 2 x 2 on the same side. I attached my first 2 x 2 on the left side and then as I assembled all the panels. If you mess up the overlap and overlap the corners differently on each side, it will not create a square. So keep this in mind with your assembly.
TrimOnce the box is assembled, it is ready for trim pieces to pull everything together! The smallest pressure treated boards that I could find were 1x4s. Originally I thought I would rip them down and make them smaller, but since my box is about 24 x 24″ around, it is pretty bulky and substantial. I decided to go ahead and use the 1x4s as is and really like the chunky appearance it creates.
These boards were cut to 24 inches in link and create a little foot at the bottom of the horizontal pieces. Again they overlap at the corners in a butt joint and you will want to arrange yours to make sure it looks good visually. I attached these with wood glue and 2 inch nails.Last bit of trim to apply is the top edge. These were added on to make things look nice and finished and cover up the seams and 2x2s on the inside. These were cut with a small overlap on each edge of the planter. They were attached using butt joints, wood glue, and nails. Miter joints would look great here, but with the elements, the wood will expand and contract a lot and I didn’t want to deal with the appearance of big gaps if my wood decided to wiggle around.
Inside SlatsOn the inside, after the piece was assembled, I added a couple of additional 2x2s to the sides in order to place some internal bottom slats. You’ll need the slats to help keep the soil in place. I placed the 2x2s about halfway down inside the planter. You could choose whatever depth works for you and the type of plants you want to put in.Then slats were added inside, just using scrap pieces I had around the garage. The slats were nailed in with my nail gun. A weed barrier liner was stapled in, more than anything just to keep the soil from falling through the slats. If you are putting another pot inside the planter, you could definitely skip this step. Sorry I forgot to take pics of this step!! 
FinishLast part to this project is finishing it up! I ran my palm sander over it lightly just to get off any extra dirt and debris and smooth things out a tiny bit. This is an outdoor piece so it doesn’t need to be perfectly smooth. I then applied Verathane black classic stain, with a satin polyurethane mixed in. I applied one coat with a clean sock, my go to method, and the piece was done!Fair warning, this large wooden planter uses a lot of soil! We added in several buckets of dirt, a whole big bag of potting soil, and some additional compost just to fill this baby up. If you want something a little bit more shallow, just raise up your side pieces and slats and you won’t have to use quite so much soil.
Hope you enjoy this beautiful DIY large wooden planter! It really looks awesome and I promise goes much quicker than reading this post! We decided to add some herbs to this planter and I can’t wait to use them this summer!
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  • Rhonda Walls Puckett Rhonda Walls Puckett on May 06, 2020

    Hi Sarah,

    The planters are absolutely beautiful! Would you mind to tell me the type of polyurethane satin stain that you used and what the mixture ratio was. I'm looking forward to building some of these planters and also LOVE the color. I'm thinking of staining my side porch this color as well and would love to use the boxes as accent areas in front of the porch to tie them all together!! Thank you so much!

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  • Beverly Beverly on Jan 21, 2020

    I was able to find wooden crates from a store that were free and used them as planters, I used dollar tree drop clith inside for to seal it so soil didnt fall out then added my big lillys and tulips and soil, my question was about how you painted yours but you answered it thank you

  • Larry wallace Larry wallace on Jan 04, 2021

    Not a question but a tip, next time you are looking for cedar, try wood fence lats they are sold individually and they only usually cost much less than treated lumber. These are usually made of cypress or cedar and won't rot. just a thought.

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    • Sarah Sarah on Jan 21, 2021

      I looked everywhere for cedar but couldn't find it! I'll definitely try fence lats next time! Great tip!

      2 winters in and my pressure treated lumber is still holding up beautifully though!