Raising the Bed | Engineering Notes
15 October 2007 at 0:00 by DrewAt long last, here are the promised photos of the new raised bed. I built one of these this Spring using some 2×4’s that I had lying around and all measurements were done to work with the boards I had. The latest bed was built using 2×4 pine studs (slightly less than 8 feet long) and were done to match the dimensions of the first bed. There was a little waste, but not too much.


When we bought the house, there were a number of raised beds already built. These were taller than the ones I built, but were not as large. A few years of experience with these beds led me to make a few changes when I built my own.
First off, I was careful to use untreated wood. The original ones appear to have a few pressure treated boards. There is some evidence that some pressure treated woods can leach pollutants (like arsenic) into the soil and from there into your food crops. For such small beds, the plants are never far from the boards, so that is something to avoid.


It is true that the boards will eventually rot and the beds will fall apart. In fact, this has been happening for a few years with the original beds. The biggest problem is that the upright supports are concealed inside the bed, in direct contact with the wet soil. When I moved some of the old beds to make way for the expanded patio, I found that these pieces were in fairly bad shape.


When I built the new beds, I moved these supports to the outside, so that they would avoid contact with the wet soil. The horizontal pieces are in no more danger than in the original design but at least will be held in place until the day that they rot all the way through. This is not as clean of a look as the previous beds, but makes more sense from an engineering standpoint.
Another thing that I did was to make the beds larger. While I did not know it at the time, it turns out that the original beds were too small for some of the helpful plant groupings that we wanted to do. Having slightly larger beds allows for more flexibility in growing companion plants. Next year we hope to take better advantage of that in the new beds.
Despite that, I think that, when the time comes to replace some of the old rotting beds, I will go back to tall beds. These low beds do still require a fair bit of stooping. They also do not provide adequate discouragement to our dog.

Still, for less than US$20, I was able to build an 8 foot by 3 foot raised bed that should last us for several years. Not too shabby.
And one last thought on this project. You will notice in some of the photos that the new beds are surrounded by bare earth and weeds. That is what happens when you are not aggressive enough in reseeding after you remove a big pile of dirt. I still need to pull weeds and reseed before the first snow in hopes of reestablishing grass there in the spring.
Tschuess.