How to Build (nice) Planter Boxes Economically

I am building cedar planter boxes for my deck to create an elevated kitchen garden. You can build one too with a few easy steps!
First let’s take a look at the finished product. The beauty of this planter box design is that it can be built to any dimension that you choose with a few simple steps. The planter box I built took full advantage of the materials I used to produce as little waste as possible.
Step 1: Gather your materials and tools.
Step 2: Measure and cut the lumber for the basic box.
You will need:
(8) – 70″ planks for the front and back (long sides)
(8) – 23″ planks for the ends (short sides)
(6) – 22″ 2 x 4s
(2) – 69 1/2″ 2 x 4s (floor supports)
Step 3: Assemble the long sides.
Lay one plank on a 2 x 4 aligning the top edges. The plank should overlap the 2 x 4 by the depth of an end plank. In this way the corners of the basic box will be level and smooth. Attach a 2 x 4 on the other end of the plank. Continue fastening four planks to the 2 x 4s to create one long side. Assemble two long sides.
If you flip over the sides, you should have something that looks like this:
Attach a 2 x 4 piece to the center of each side for a brace. (This is where I made a mistake.)
Step 4: Attach the floor support.
Decide how deep you want the soil to be in your planter box. Then measuring down from the top, attach a floor support to each side. Use 2 1/4″ or 2 1/2″ deck screws. You may need to drill your holes first.
Step 5: Build up the short sides.
Line up the long sides. Starting at the bottom, attach a plank on each end. Build up the ends one plank at a time.
At this point, you could skip to Step 7 (cut your floor boards) and call it a day. This would reduce the cost of your planter by a little over $33. However, I chose to trim out the corners and top to make a more finished look.
Your planter box should now look like this (except for the center brace):
Step 6: Trim out the corners and top.
Measure and cut eight trim boards for the corners. Attach the trim boards with finishing nails.
Measure and cut trim boards for the top. Miter each corner 45 degrees for a polished finish. Use finish nails to attach the boards.
Step 7: Cut the floor boards.
With the remaining planks, cut floor boards measuring 22 1/2″ long. You will need 13 floor boards, however, the last board will need to be cut in width to fit your box. Using a hand saw or jigsaw, cut the floor boards to fit around the 2 x 4 pieces.
Step 8: Do your happy dance!
You have just completed a very attractive planter box at a fraction of the cost had you purchased it as a kit or fully assembled! You are a financial carpentry genius!
The finished planter:
For more details and a few tips, visit the blog:
My planter cost me just at $115.00 excluding tax. I did have a box of the longer (2 1/2″) deck screws that I did not have to buy. I purchased all of my materials at The Home Depot.
What’s next? I will be staining my box with a transparent outdoor stain…probably Thompson’s WaterSeal. This isn’t necessary, however, cedar does turn gray as it weathers and ages. I will be lining my box with a commercial grade landscaping cloth and filling it with good soil in preparation for planting those seedlings I hatched recently (see that post here) and planting more seeds.
Oh, don’t you just love spring!

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Have a question about this project?

3 of 5 questions
  • Gov31193198
    on Oct 9, 2017

    Lovely planter, but why no dranage holes?
    • Derik
      on Sep 1, 2019

      Doesn't need drainage holes because there are gaps between the floor planks that will suffice for drainage.

  • Olive harte
    on Dec 29, 2018

    how can I keep this waterproof as Ireland is damp in the garden all winter?

    • Carole
      on Jan 24, 2019

      How about Johnson's paste wax? I'm not sure if you have tried this works excellent on the boat. (Bowling alley wax)

  • Sha
    on Jun 13, 2019

    I used fabric spray paint on a fabric covered bench. It became stiff. Is there anything to use to soften it or does it need to be recovered?

Join the conversation

2 of 8 comments
  • RUSS
    on May 3, 2019

    I like this planter and your directions. I did add drain holes. Most plants do not need deep soil to thrive. One foot is more than enough. I lined mine with heavy gauge plastic (6mils). This protects the wood even though you are using cedar. I also added hidden wheels so the planter can be moved easily.

  • Jim Cox
    on Jul 23, 2019

    This look is so simple and clean. Between you and one of the HT peeps on Facebook, I don't see a planter but a great bench for my deck with storage! Grill tools etc

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