
A day or so ago, a member,
@Land of Lincoln asked me how many pallets does it take for me to build one of my pallet wood raised bed v2.0 designs? The short answer was about 3 pallets broken down and cut into correct sizes.

It occurs to me that some people maybe are looking for a simple design that uses less pallets. With that in mind, I would like to post a YouTube video that makes a nice, raised bed out of one pallet. Here is that video...
I think you could build a perfectly fine pallet wood raised bed that way. Obviously, the benefit of that design is it was an easy build with few cuts, he used 2X4's in the inside corners to strengthen the raised bed, and with a good pallet, he made a complete bed out of just one pallet. Considering the reduced time and effort for that build, I think you would get years of service out of it before it needed to be replaced. If that sounds good to you, then try it out.

Now, let me tell you a little back story of how I came up with my v2.0 design. I originally built some raised beds using the method in the above YouTube video. I added the 2X4's in the inside corners for extra strength. It was a fast and easy build. Let's call that pallet wood raised bed v1.0.
I was really happy with those v1.0 raised beds for a number of years. However, after 3-4 years, the wall boards started blowing out at the corners from the pressure of the heavy soil and the wood getting weaker. Your experience may be shorter/longer depending on your weather conditions.
In any case, I set out to strengthen my v1.0 design, addressing the issue of side wall panels blowing out, especially at the corners. That was the main point of failure in my v1.0 beds.
So, I decided to put the 2X4 framing on the outside of my v2.0 raised beds. And I used additional 2X4 pieces in the corners to really make those corners strong. The framing of my v2.0 design is rock solid. Now, to keep the sidewall boards from blowing out, I moved them from the outside of the frame to the inside of the frame. The soil pushes the wood into the framing, holding it into place. It's got nowhere to go. Again, extra strength for the walls.
With that in mind, here is a picture of my pallet wood raised bed v2.0 design that I currently prefer...
View attachment 4177717

I have had some v2.0 raised beds for about 4 years, and they are holding up just fine. No signs of structural weakness like I eventually noticed in the v1.0 design getting weak at the corners.
The only issue I have had with these pallet wood raised beds is that sometimes a wall board or two will warp in the middle of a board towards the inside of the bed. None of the soil in the raised beds has fallen out, but I have replaced a couple of boards for cosmetic reasons. I just dig down the side of the board, remove it, put in a new board with some brad nails, put the soil back, and repair job done! No problems with repairs that way.
I saw one guy comment on the warping of pallet wood in his raised bed. His solution was to add another 2X4 on the inside of the box, sandwiching the pallet wood wall boards between the inner and outer 2X4's, preventing any warping of the wood. If you get a lot of warped boards, keep that solution in mind. For me, it was just a lot easier to replace a couple boards, over 4 years, in the ~8 pallet wood raised beds I have built.
Here is a picture of a warped board that I replaced last year. You can see that the soil is still confined inside the raise bed. But I wanted to replace that board for both cosmetic reasons and to see how easy/hard it was to replace a warped/rotted board in the future. Turns out, it was an easy fix that only took a few minutes...
View attachment 4177831
My solution going forward is to leave a slight gap between the wall boards to allow for expansion, hopefully preventing warping in the future. After 4 years, that is the only issue I have noticed. That is not too bad considering the quality of some free pallet wood might not be the best.
Overall, I could not be happier with my pallet wood raised beds.