03/25/2026
For anybody planning on building a raised bed from wood, please read this. I have built several over the years with great results. And I am planning on building a couple more.
Never, ever use pressure treated lumber for a raised bed that will ever see food grown in it.
First of all, if you're planning it for longevity I'd recommend using red cedar lumber. This will cost a lot of pretty pennies, actually hundreds of dollars, but the wood itself looks great when new and it ages well, so you get an ornamental use too.
Secondly, if economy is more important than longevity I will tell you that untreated lumber is an option. Maybe a five year lifespan, but options are plenty. Any naysayers probably read it in a book or bought junk lumber.
The following is true for either type of lumber.
Never paint, stain or apply any preservative to the inside of the bed if you are going to grow anything to eat from it. The outside can be treated, actually decorated, there wouldn't be any connection to your veggies or fruits.
Only buy quality lumber, the type you'd want to use if picking lumber to build your forever home with. Small knots are okay, stay away from any center cut lumber. That stuff will fall apart faster than rot into oblivion.
I refer to the wood used for raised beds as lumber because I'm talking only about "2 by" thickness lumber. From a lumber yard it will measure one and a half inches thick and be 2x6, 2x8 or 2x10. The prices are different so you may save money by choosing different widths to get the height you want. Rough cut lumber will actually be 2" thick and that may look better than commercial lumber. My beds are built from two or three separate boxes that get stacked upon each other. The soil and the corner supports keep the boxes alligned.
When I built my first two raised beds I copied what I had seen how shipping crates for heavy granite blocks and also steel tools were built. I had acquired several empty ones of those and removed the bottoms. They were built of "2x" lumber with reinforced corners. They lasted for years as starter beds. That is where the strength to resist pushing apart from freeze thaw cycles will be.
I use simple butt joints to assemble the beds. On the outside at the corners I have the joints reinforced with "L" shape lumber. The only fasteners I use are screws, at least two 3" deck screws to pass through one piece of lumber and draw tightly into the other piece. Deck screws are treated to prevent rusting. Never use drywall screws as they would fail either by rust or snap from the freeze thaw cycle. Plan to be generous using the screws.
Just a note to think about hardware cloth. I put 1/2" galvanized hardware cloth on only the bottom box to deter voles from tunneling in for meals. I first staple it with an Arrow stapler to hold it in place and follow up with poultry fence staples to last the life knowing the Arrow staples will be rusting away soon.
My need for raised beds really began when we moved into this 55+ community. The 1" of soil is hardly enough for a lawn to grow. Most plants need a half foot of soil to grow good but the roots would go deeper if the soil would allow. We also have only underground utilities.
If we dig down to replace the gravel with soil we are required to call Dig Safe. I've heard of that failing way too many times and disaster. So by building up I can avoid that drama. I get the benefit of setting a chair alongside to w**d or thin plants or use the bed to push against as I struggle back up from kneeling.
I'm going to show my two beds built in '22 and '23 and I'll show you in another post what I did last fall to modify my corners. Keep in mind the '22 bed has seen four freeze thaw cycles and the '23 has seen three. The joints are still better than most contractors call good for just built home construction. You can do this too.
Press the photos for captions.