I was out in the main garden this morning planting some Roma tomatoes in one of my earliest raised beds built from using fence panels. Basically, I had a number of 4-foot-high wood fence panels that were not being used for anything, so I cut them in half down to 2 feet high and made these raised beds about 5+ years ago.
Now, I have mentioned that using framing on the outside of my pallet wood raised beds is a much sturdier design than having the framing on the inside. All my new pallet wood raised beds have the 2x4 framing on the outside for increased strength. What I am going to show you with the following pictures is what time and outward pressure can do to raised beds if you don't have the framing on the outside, like I did years ago when I built the raised beds with the fence panels.
First of all, let's look at a blowout. Here is what time and constant outward pressure can do to your raised bed without framing on the outside...
View attachment 3525839
That corner gave out because the wood inside the corner piece softened up and the screws holding that corner came out due to the constant outward pressure of the soil inside the raised bed. Mind you, this raised bed is just over 5 years old, and I can't complain too much about how long it has held up, but I think if I would have used framing on the outside of the build it would have lasted longer.
When I fix this problem, I think I'll just use some salvaged 2X4 wood and build a frame for the outside. The bed is 4X8 feet, so I need to use some of my longer salvaged wood or long pallet 2X4 to rebuild this raised bed.
In addition to the corner blowout, you might start to see sidewall pieces blow outs for the same reasons. This fencing panel that I cut in half does not have any sidewall pieces blown out - yet - but a few have rotted and will need to be replaced.
Another issue that I learned from building these first 4X8 beds is that you can get significant bow out in the middle of the 8 foot side. Here are some pictures of how, over the years, the sides of one of the raised beds is starting to fail...
View attachment 3525813
I put a straight rake handle in this next picture to give you a better idea of how much the sidewall is bowing out. The only way I know how to fix this problem is to rebuild the raised bed and add some cross support pieces at the half-way 4 foot mark.
View attachment 3525814
Well, lessons learned on all of these early attempts at making raised beds. I think my new designs using pallet wood and having the 2X4 framing on the outside has been a better idea to prevent blowouts and keeping each raised bed to 4X4 feet should eliminate the bowing out problem with the longer 8-foot sidewall.
Having said that, these fence panel raised beds are 5+ years old and my newer 4X4 foot pallet wood raised beds are only a couple of years old. So, time will tell if my newer designs with 2X4 framing on the outside will hold up better. I think they will.
Picture of my newest pallet wood raised bed design with framing on the outside, for comparison....
View attachment 3525817
If you have any thoughts or experience in your raised bed builds, I would love to hear your comments. I hope to learn from my mistakes, but it is always better to learn from others mistakes and not make the same ones. In that light, I offered my experience from building raised beds and I hope others will not make the same mistakes I made.