A few readers have asked for more specific information about building raised beds, so here’s an addendum to my last post.
I’m writing this with a bit of a caveat, because these raised beds were made with no plan and no research, using only scrap and salvaged materials. There could easily be a design flaw that I won’t discover for a month or two. Then again, this has got to be the simplest woodworking project you could undertake, so it doesn’t seem like total failure would be a big risk here.
Each bed is basically a big frame set on the ground. The dimensions are roughly three feet by seven feet, and the sides are about a foot high. We didn’t have enough wide boards so some of the sides are made by stacking two thinner boards.
The only slightly tricky part is joining the boards together at the corners. Here sections of 4×4 post were used, each cut a little longer than the sides of the beds. We drilled the boards into the posts and this kept the frames square.
Altogether we made five beds, and we placed them two feet apart, enough space to get a wheelbarrow in between the beds. The frames were filled with a 50/50 mix of compost and topsoil which was delivered from a nursery. The soil compacted once it rained, so we should have added a little more soil in the beginning.
The only caution I can think of is not to use older pressure-treated lumber, which can leach arsenic into the soil. Soilborne contaminants and heavy metals can get taken up in plant tissue so you want to keep these far away from anything edible.
Good luck if you try this project! And definitely let me know how it goes.