
I have a new house. It’s natural at this time of year to want to plant things, I think. But our ground to is slanted, sloped Rowan the north, covered by a lot of trees, and not well suited for vegetable gardens. As a result I’m building planter boxes. I used this tutorial for inspiration.

Originally, these boxes were going to be 4×8, for what’s known as “square foot gardening”. Most plants have pretty standard placements: four to a square foot, twelve to a square foot, one to a square foot, and so on. Planters of known sizes and depths make it easy to estimate these numbers (allegedly).
However, due to questions of movability and sunlight analysis, I wound up chopping down my 16’ boards into 4’ boards. I have only two places that I can put 4×8 beds easily, and both get little sunlight. I have 6-8 places I can put 4×4 beds. (It does alarm me that each 4×4 bed can hold 13 cubic feet of dirt — at going prices, that might set me back $300-400. Yikes!)

The design of these boxes is pretty simple. Each is a 2×10 (nominal— milled, they’re down to 1.5×9) — cut into 4’-sections. The corners are screwed into each other, producing a box. Then, sections of 2×4 are screwed down to the top to provide strength and a “sitting place” while weeding, inspecting, pest-controlling or harvesting. You can use hugelkulture techniques here, filling the center part of the box with twigs, sticks and split logs which will rot and turn to soil (reducing the amount of dirt you need to fill in on top).
You can also line the bottom with cardboard and shredded paper, to create a layer of fast-mulching materials and to prevent weeds and grass from growing upward.

On the interior of the box, cleats made of 2×4 scraps help stabilize the box, and give an extra layer of support to the ring of 2x4s around the top. One scrap goes in each corner, and in the middle of each of the “long” sides of the box — that is, the sides that are 4’ long plus the two “end caps” of the 2x10s.

The result is a pleasant-enough looking garden box. These are made of untreated lumber — because if you use treated lumber, you will kill your plants (or worse, they’ll survive, and you’ll wind up poisoning yourself). Use untreated lumber.
It’s worth saying that for this project I used a measuring tape, a carpenter’s square, a Stanley hand saw, and a Makita power drill and bits. You can also see the two saw benches that I built five years ago (rather poorly, I’m sorry to say). The tool set I used to build this would cost about $150 new today; the wood and screws and so on probably set me back another $120 for four of these boxes ($67.50 apiece, roughly… or $30 apiece since I already had the tools — but I still have to fill them with dirt!)
It’s the “dirt” part that’s upsetting me right now. As the saying goes, “for all our vaunted technology, human civilization is still dependent on 3 inches of topsoil and the fact that it rains.” My four $70 boxes may cost $1200 to fill with soil. And I still haven’t eaten a single homegrown cucumber. Alas.
That’s a lot of money for soil.
Was it always that expensive in your area, or is this a first sign of mounting inflation?
If soil is super-expensive but lumber isn’t too bad you might consider modifying one of the boxes to operate as a large-scale cold frame in the off seasons.
For lumber preservation, here is a raised-bed maker called Gronomics that has an allegedly non-toxic wood preservative for their frames.
While I think of it, see if your state has any virtual garden shows. For the two cubic meters you would need you can probably get some kind of discount.
It is a lot of money for soil. I don’t know that it was always expensive in our area, but it’s not exactly cheap. And it may be that I’m just operating off of a couple of numbers I saw at a local big-box gardening store, rather than what can be had at a reasonable rate.
The point about cold frames is a good one. I think that I’m going to make two of these small 4×4 boxes, and then build a cold-frame for a full size 4×8 for next year. The cold frame design I’d do, I think, is this one, which is simpler and easier to build around here than one with glass windows.