How to Build a Tiered Garden Planter Box

This Spring has been such a tease. Every time it felt like we were turning a corner, BOOM, more snow. Or just cold rain. And don't get me wrong, we live in a major potato farming community (classic Idaho, amirite?) and I'm happy that the farmers will have plenty of water this year, but sometimes I just need to see that sun and feel its warmth on my skin! Which I guess is when you take a trip to Hawaii. But! This past week has been exquisite. A little rain here and there but mostly sunny, warm, and perfect for buildin' stuff! And what better Spring project is there than making some planter boxes?

Some of our long, long time readers may recall our planter boxes from our last house. They were great and all, but they also were going to take up a large portion of the yard and an even larger portion of our time to keep weeded and tended to. I mean, I have plans of one day being this master gardener with the north side of our backyard filled with organically grown fruits and vegetables, but for now I have a hard enough time remembering to water my basil plant in our kitchen. And it sits next to the sink. Where all the water comes out. So we wanted to ease ourselves into the world of horticulture with a few tiered garden boxes for the back deck.

A tiered garden box presents a few challenges. In essence, we decided to build 3 separate garden boxes where each is structurally designed to support the other. You also need to plan for drainage, to prevent mold and fungus, and make the planting areas deep enough to allow space for the plants you plan to plant (yeesh, that's a mouthful) to catch root. Here's a little rudimentary drawing we did:

One minor change - the boxes (we built two) ended up being about 39in tall instead of 36. The rest of it stayed pretty close, though not exact and I'll explain why in a bit.

Materials Needed - Total Cost: $170
• Redwood 2x2x12 Deck Baluster - 9
• Cedar 5.5x6 dog ear pickets - 25
• 1lb box of 2.5in decking screws - 2 boxes
• 1.5inx.25in finishing pneumatic staples - 1 box

Tools Needed
• Measuring Tape & Pencil
• Impact Driver w/bit set
• Miter Saw
• Table Saw or Circular Saw
• Pneumatic Stapler
• Air Compressor w/hose

You may also want to have a pry bar, hammer and some needle nose pliers handy.

First let's talk choice of wood. Cedar is pretty common for garden planters because it's naturally weather and bug resistant, and develops beautiful patina and weathering over time. Unfortunately, cedar can be pretty expensive. For a standard 1x6x8 cedar board you're looking at $14 each, and that's if you get a good deal. With how much cedar we'd need, that would be nearly $300 just to have enough cedar for one planter. For that reason, we used cedar pickets.

Now I want to set proper expectations on this. Cedar pickets are not some miraculously versatile yet untapped product that is just as good as the milled stuff. There are compromises you make when you use cedar pickets, and if you aren't ok with a finished product that has a bit of... we'll call it "character," then you should plan on spending a bit more money. You'll often find boards that are bowed two or three different ways, and getting that to look uniform can be tricky. The edges can be uneven and even the width of the planks themselves can vary by up to a quarter inch. This makes for an interesting project, BUT it saves a lot of money, it stays put once it's stapled in place, and Jules and I both love the way it looks when finished. I don't want you to think that using this product will yield a garden box that looks like a 3rd grade child's sculpting project, but it is something to be aware of. Just take your time picking through the lumber pile and get as many flat boards as you can.

For the actual frame of the planter box, you want to keep the whole thing pretty light weight, so a 2x2 works best. Unfortunately, pine 2x2 studs are notoriously prone to warping and aren't very weather resistant. So I suggest splurging a little and getting redwood deck balusters. They warp much less, and redwood is also weather resistant. But, since it's a 2x2 you end up with a much lighter planter box that is still sturdy. So, let's take this step by step. Your measurements may vary, depending on how wide you want your planter box to be. Adjust as needed for your situation.

Base Tier Construction
Note - all framing is done with screws, all planks are added with pneumatic staples. When screwing the frame together, always predrill with a 1/8in drill bit to prevent the wood from splitting.

To find the dimensions of the frame, take the desired size of the finished box and subtract the thickness of the cedar planks x2 for each axis. For example, we want our finished box to be 56in wide. The thickness of the cedar planks is 9/16, and since there will be planking on each side, you double that to 1 1/8in. Subtracted from 56 you end up with a frame that is 54 7/8in. We do the same for the depth, coming up with 26 7/8, giving us a frame of 54 7/8x26 7/8.

Cut two pieces of the redwood 2x2 to 54 7/8 for the front and back base frame pieces. Now for the side frame pieces - subtract the combined width of the front and back 2x2s from 26 7/8. the 2x2s are actually only 1 3/8in thick (2x2 is predried dimensions), so that leaves us with 24 1/8in. Cut those two pieces and screw everything together in a box (remember to predrill).

Now build the top frame of this bottom section, which will match the dimensions of the bottom of the second tier. This is the same width as the bottom frame, with a finished depth of 18 7/8 (20in subtract 1 1/8). Set the top frame on top of the bottom, with the back sides aligned.

Mark on the bottom frame where the front of the top frame ends. Measure and cut a 2x2 to fit inside the bottom frame, and position it so the back of it lines up with the front of the top frame (where you drew the lines).

Now you need to calculate the height of the bottom section and cut the studs. Again with the math - the cedar planks are 5.5in wide. Our bottom section will have three (3) cedar planks, giving us a height of 16 1/2in. Subtract 2 3/4 (the combined width of the top and bottom frame) and you're left with 13 3/4. Cut ten lengths of 2x2 to 13 3/4in. Set four pieces aside for now. Attach four of the remaining six to the bottom frame, where the four corners of the top frame line up.

Cut two additional 2x2 lengths to 15 1/8 in (the total height of the bottom segment, minus the thickness of the top frame) and screw these, evenly spaced, to the bottom of the front piece of the top frame (got all that?) and the back side of the middle support of the bottom frame. Then attach the two 13 3/4 pieces, evenly spaced, along the back of the frame.

Measure the width of the area from the front of the bottom frame to the back of the middle support of the bottom frame. Cut 10 lengths of cedar planking to that length and attach, leaving about 1/8 of an inch between each to allow for drainage. The last plank will need to be trimmed down on your table saw or with a circular saw.

Add planking to the sides and back of the bottom segment. Measure the sides to extend all the way to the front of the bottom frame. Mitering the corners is more difficult with cedar pickets, but looks nicer when finished if done correctly. If you'd rather not miter the corners, simple cut the sides to the exact depth of the frame, and allow the front and back planks to overlap the sides so the seam is not visible from the front.

Plank the current front side of the bottom frame before adding the rest of the front frame. This is important, because the pneumatic stapler won't fit into the space once the front is on, so that's why we wait to put that on last. The bottom plank will need to be run through the table saw or cut with a circular saw so its top lines up with the tops of the two bottom side planks. This will keep your spacing even.

We don't want 2x2 sticking out of the dirt, so we're going to miter cut our front 2x2 supports (the four 13 3/4 pieces we set aside earlier) at a 55 degree angle.

Predrill and attach these to the front of the frame, with two in each corner and the other two spaced evenly in the middle.

Once in place, use the stapler to attach the side panels into the newly added supports. Then finish paneling the front.

You still with me? Whew, that was a process, huh? But now look what we have! The back section is of course the base of the second tier, and we have our front portion for planting. The inside of the planter area of each tier will be lined with landscaping fabric, and we'll pour about an inch or so of gravel in the bottom to allow draining while keeping the soil from being washed out over time.

Ok, back to it.

Second Verse (tier), Same as the First (except smaller)

Rinse repeat, only adjust the measurements. so this time, your base frame will be the same size as the top from of the previous segment we made. Also, this tier is shorter - only 11 inches tall, the combined width of two cedar planks.

Attach the 2nd tier to the bottom tier with screws around the perimeter, including the front in the bottom of the planter area.

The Top Tier

This is the easiest one, since there's no supportive section. It's just a planter box. Build the base, which has the same dimensions as the top frame of the 2nd tier, and add the cedar plank bottom.

Attach the angled supports, evenly spaced.

Once those are in place, simply add your planks and attach to the top of the planter box.

And you're done! Well, unless you're like me and you need to make two of these. Then you're only halfway done. But still, yay! Good job! Of course once they were finished we had to move them in place.

Jules and I went directly to the nursery after finishing these and picked up a bunch of plants. That's what we'll be working on today and we hope to show you what they look like, all greened up, on Thursday. My guess is, they'll look awesome.

Now if only we can get the rest of the trees to finish filling in and finally get our privacy back. ;)