Building Raised Planter Boxes

Building raised planter boxes is very easy, and usually more cost effective than purchasing them. Follow this easy DIY raised garden box tutorial for an easy design, step-by-step instructions and cost breakdown.

This is one project that I got the most questions on when I shared in-progress photos and videos on social media. I am excited to have this tutorial ready for you! This really is a super simple and easy raised planter box design, perfect for garden boxes which is what I used it for.

The first thing you need is the right sized wood. Cedar is the best to use because it is the most durable, but I couldn’t find any cedar near where I live so I just used what I could find and built my raised planter boxes out of a “moderately durable” rated wood.

The size you want to purchase is going to depend on how high you want your finished boxes to be. You can purchase wood 6, 8, 10, or 12 inches high. Since the design I used was very simple and I wanted a higher side on my planter boxes, I used 10-inch high wood. The 12-inch would have been a great option as well, but I wanted the savings on building the boxes and filling them.

The length is also important. Using 8 foot long planks of the wood works best because it allows you to build boxes that are a reasonable size to work in once planted and make minimal cuts to the wood you’re using. Three boards makes up one box – two long side boards and then on board cut in half for the ends, the final raised planter box being 8 feet long and 4 feed wide.

I experimented heavily with box size when I was still using my DIY garden boxes I built from stacking rocks, and the 8×4 foot size is my favorite. You can reach the middle easily from the sides and it’s easy to get a rake or hoe across for working in the soil.

Since we build 20 boxes in all, I sorted out 40 pieces of wood for the straight edges and then cut 20 pieces of wood in half. It’s much easier to assemble the boxes if you make a straight cut. Here is how to get a good, straight measurement.

Measure 4 feet from one end of the board and make a mark close to one edge.

Do the same thing on the opposite edge of the wood so that you have two tick marks both at 4 feet.

Use a straight edge to connect both the tick marks. This makes sure your line across is nice and straight. But just because you have a straight line doesn’t mean your cut will be straight….ask me how I know. Ha! I’m not the best with the saw, but the great thing about this design is it’s very forgiving and even with my bad cutting skills the boxes went together easily.

We joined the edges of the boxes together very simply, with just three screws on each side. We used 3 1/2 inch screws so that the joint was strong enough. You’ll definitely need to drill pilot holes and have an extra drill battery on hand if you are building more than a couple boxes. They go together fast but drilling all the pilots and screwing the screws in uses a lot of battery power.

Since I am building this new garden area for my CSA, I wasn’t sure how many garden boxes I would need total until I closed share sales. As I mentioned before, we ended building 20 raised planter boxes, using 2 apple bins for potatoes, and building a strawberry planter {tutorial on that coming soon!}. I’ll definitely be updating this post at the end of the season with more pictures of things actually growing in the garden boxes. We stacked the raised planters until I decided where I wanted everything to go, it was quite the stack!

The other essential part of building raised planter boxes is filling them! You cannot just put any old dirt in your garden boxes and expect your plants to thrive. We actually have great soil here, but on our property, the rocks are so bad I can’t grow and pull carrots or any root vegetable successfully. And, since our property was unmanaged for more than 10 years, the weed-seed load is outrageous. I’m hoping to be able to minimize the weed seeds and manage weeds better by using these raised planter boxes.

I purchased a very high-quality sandy loam topsoil for the boxes and then added peat moss and pearlite {helps with soil compaction} to the top inch or so of each box. Later I will add more composted material, but since I moved our entire garden area I didn’t have a composting situation set up yet.

Here is a cost breakdown for making and filling 20 raised planter boxes {I’m in Utah, pricing will vary depending on your area}:

• Wood: Each plank was $12, I used 60 planks to build 20 boxes so the total cost for wood {after tax} was $780.
• Screws: I bought a contractor pack that was 5 pounds for $24.
• High-Quality Soil: I had 14 yards {1 giant dump truck load} delivered and it was enough for all 20 boxes and cost $380 after tax.
• We already had a skill saw, the drill, bits, and a truck to transport that much wood easily.
• Total cost to build 20 raised planter boxes: $1,184.
• If you wanted to calculate one box, it would be roughly $60 a box which is still much cheaper than purchasing a box, remember that total price included filling the boxes with dirt.

Now, is it in everyone’s best interest to build 20 raised planter boxes? Nope, probably not. If you have workable soil that you can manage it will be less expensive to just garden in the ground. But as I said before, I wanted the extra control of gardening in boxes and I like the way it looks. It’s also much easier for me to manage verticle growing, which makes the expanded space gardening in raised planters takes up worth it.

It’s going to be a great gardening season! I can’t wait to show you more updated pictures as the season progresses.