Today I’ll show you how to build a DIY Raised Planter Box. We’ve been wanting to have some type of elevated planter for a while so we can grow herbs in a small controlled area. I also make a Patio Cooler Grill Cart Combo a couple years ago and it’s a great match on our back deck.
I’m partnering with RIDGID Power Tools for this build for Father’s Day. You can get the DIY Raised Planter Box Plans and build your own too! Huge thanks to RIDGID and I hope you can build one and enjoy it with your family as well.
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How to Build a DIY Raised Planter Box
- Build the Leg Assemblies
- Assemble the Main Planter Box
- Make the Lower Shelf
- Make the Top Frame
- Install the Bottom and Drainage
- Apply Finish and Final Assembly
- Install the Liner and Plastic Sheet
1. Build the Legs for the DIY Planter Box
I started off by making the planter box leg assemblies. Each leg is made from two 1x4s joined at a right angle. Since I’m using a butt joint, one side of the leg assembly would be ¾” wider than the other without any modification. So I cut ¾” off the width of four legs and each side of the assembled leg will be 3-½” wide.
I’ll be joining the legs together with a combination of pocket hole joinery and glue. I only made holes where they would be covered by the legs or the lower shelf.
Next I put glue on the edge of the narrow piece and clamped it to a full size leg part and secured it with exterior pocket screws. I used a small f-clamp to clamps the parts together while the glue dried. I repeated this process for all four legs and set them aside to dry.
Then I moved on to cutting the front, back and side boards for the DIY planter box. I laid out my cuts so I get two fronts and four sides from a 12’ board. This will give me a consistent color wrap around the box. I cut the long boards first then moved my stop block in and cut the shorter side boards.
Next I put a small chamfer on the edge of each of the boards that make up the box with my router. This adds a nice little detail to the planter box. Since I’m not gluing the boards into a panel this will also help to hide any gaps between the boards.
Before assembly I sanded everything to 150 grit with my cordless sander so it will be ready for finish after it’s assembled.
2. Assemble the Main DIY Planter Box
First I laid two of the leg assemblies out and used side pieces at the top and bottom as spacers to make sure everything was parallel. Then I put down a nice bead of glue where the boards would go and attached the the side panels one by one with exterior screws. I repeated this process on the other side and had my two planter box side panels done.
After that I clamped down a scrap of plywood to my bench as a straight edge reference to join the sides together and form the main planter box. Then I butted the sides against it and laid down some glue and put the top and bottom boards in place. I used a long clamp on the top and bottom of the panel to position the panels while I attached them with 1-1/14” exterior screws.
Finally I finished off the other side by flipping the assembly over and repeating the process.
3. Make the Raised Planter Box Lower Shelf
Next I went back to the miter saw stand and cut boards to size for the lower stretchers and for the front and back battens. Each of these pieces is 1-½” wide so I cut them to size on the table saw.
I laid out the position for the lower shelf stretchers and glued and screwed them to the legs on each side.
While the planter box was still on its side I attached the front and back battens. I centered each batten then secured it to the top and bottom boards with screws then put a screw in each board to hold them all flush in the same plane.
Next up I cut eight slats all the same size for the DIY planter box lower shelf. To keep the slat edges from chipping and to add a little detail I put a small chamfer on the top edges of each board with my router. When routing all the edges of a board do the end grain first then the long sides. The ends are more prone to tear out and a second pass on the sides will help clean up any tear out that may happen.
I’ll be screwing down the slats to the stretchers so I predrilled holes on the end of each board. To get the consistent spacing and a nice clean look (which you guys know I love) I used a little plastic cabinet hardware mounting jig and drilled an extra hole in it. It worked great and gave me exactly repeatable holes..yay, OCD!
To align the slats on the bottom I started off using some scrap spacers, but ended up just lining them up by eye since my spaces ended up a little under ¾”.
4. Make the DIY Planter Box Top Frame
Next up I cut the parts for the top frame. It’s a simple mitered frame from full sized 1x4s. I started by cutting 45’s one of the short parts to size. I used that part to mark the cut for the second short piece to cut it the same length.
For the long frame parts I got a little smarter and made a 45 on two boards then stacked them together and cut the other sides at the same time. This made getting the same length a lot easier.
I drilled pocket holes on the underside of each end of the short pieces to give the mitered joints a little reinforcement.
For assembly I laid out the parts upside down on my bench and applied a liberal amount of glue to the short boards. I used a web clamp to pull everything together and referenced each of the corners with a machinist’s square before screwing them together with pocket screws.
Okay, be honest. Who realized my DIY planter box in the thumbnail had a 4 board front panels vs the 5 board panel you see here? Well this was the exact moment I decided the look of the planter box was off. The fifth board made it look way too chunky and the drainage system I figured out didn’t need the extra space anymore.
So I swallowed my pride and took a lesson in failure and setbacks. Luckily I’d not glued the pieces together as a panel, so I was able to use a flush cut saw and remove the panels pretty quickly. Unfortunately the ends were still glued and it took quite a bit of time and persuasion to remove the bits with a chisel. But in the end I’m glad I did it.
5. Install Bottom and Make the Drainage System
The last piece of the elevated planter box was the bottom and the hidden drainage system. The bottom is split into two sides and I cut four cleats to hold the bottom slats.
I laid out marks for the cleats so they had a ½” slope from the outside to the middle of the planter box. Then I predrilled each cleat and secured them to the sides with screws.
For the bottom boards I used the worst of the boards I’d picked up from the lumber yard. I cut them to size then predrilled a hole on each end and laid them in the planter on the cleats.
One thing I’d not seen in other DIY raised planter box plans was a good drainage option. So I wanted to try something different. The heart of the hidden drainage system is this 2”x3” PVC downspout. I positioned the inner bottom boards then secured the boards to the cleats.
Then I just evenly spaced out the rest of the bottom boards and secured them to the cleats as well. I marked off some lines on the PVC that would let the spout stick out past the planter. Then I cut that section out using some tin snips.
After that I cut the piece sides at an angle and to allow for runoff drainage. But before I attached it in place I wanted to apply my finish and attach the top frame.
Since I forgot to cut pocket holes in the top of the panels earlier I did them before I finished the planter.
6. Apply Finish and Final Assembly
For the finish on the raised planter box I brushed on two heavy coats of spar urethane. I really love how the spar brings out the warm tones of the cedar. And it protects well outdoors.
When the finish was dry I went back and installed the hidden drainage. I just predrilled some holes in the downspout and attached it to the sides of the bottom boards. I’ll show you how it works after I install the liners.
Before putting in the liners I installed the top with pocket screws in the holes I drilled earlier.
7. Install the Liner and Plastic Sheet
The second part of the DIY raised planter box drainage system is a combination of landscape fabric and plastic sheeting. I started by covering the bottom with a layer of the landscape fabric. You really only need a small piece but I covered the whole bottom anyway stapling it in place and made a little trough right over the downspout.
The fabric will keep the soil from clogging the drain. The main part of the planter box liner is the black plastic sheeting. I used a 3.5mil sheeting since it seemed like the most heavy duty but not expensive.
I unrolled and worked the plastic liner into the planter box, stapling it at the very top under the frame. Then I poked four large holes in the plastic right above the downspout to let the water escape out of the elevated planter box.
Of course I had to test out my contraption to see if it really worked. The planter drained right out the back just like I’d planned and will keep that bottom shelf clean and dry.
We took the planter box to the yard and filled it up with potting soil and plants. This is a great Father’s Day project to use the planter box to garden with your family. We plan on growing some herbs and veggies and letting the kids care for them.
Remember you can get the DIY Raised Planter Box plans for your own raised planter box build. Let me know if you make it!
If you liked this DIY Raised Planter Box you can check out some of the other outdoor projects I’ve built at my Outdoor Projects page.
RIDGID provided me with product and/or monetary compensation as a sponsor of this build.