Building raised planting beds

My Memorial Day project was building some more raised planting beds for the garden. We use a lot of them; it makes more sense to prepare some intensive growing places than work a huge plot, then not use 100% of it.

My goals was something easy to build, strong, that would last many years, and not be too expensive. My first two choices were redwood or cedar; they are naturally resistant to rot and hold up well. I wanted to avoid anything that had been painted, made of plywood (nasty chemicals in the glue), or especially pressure-treated wood (they use arsenic among other nasty chemicals, hardly what you want for anything you'd ingest).

We've been doing this for a long time, and have tried all sorts of shapes and materials. The ideal size seems to be about three feet on each side, and one or two feet high. Any smaller and they get too hot, and if they get bigger, they require more expensive materials and seem to be more of a problem to keep weeded. One foott high is fine if you have ground that the roots can work their way through. Our gardens are located where horses had been pastured for 20 years, and the soil underneath was on its way to being a nicely fertilized and aerated. Most of the rest of the yard is hardpan "adobe" clay and difficult to work with. By extending vertically a few feet with some rich soild, we have a great situation.

I scoured the local salvage places, but nobody had anything suitable. I ended up at Home Depot; decent prices and selection, and they are everywhere. I got some six foot 1x6 dog-eared redwood fence boards for $1.97 apiece, quite a deal. It's rough and has a few knots, but no weaknesses; perfect for beds.

Cut them into two three foot lengths. The easiest way is a radial arm saw or table saw, but a Skil saw or hand saw will work well but will take a little longer. I do all my cutting at once, to get it over with.

To hold it together, I put a one foot length of 4x4 in each corner (or two feet, if you are making them that high; these directions are for one foot beds). I used Douglas Fir, which isn't as rot-resistant as redwood, but is a third the price. They are nice solid posts with no defects, and should last many years. At the right, you can see the first step. I laid a couple of one foot post sections on a work surface and screwed the first plank down with a single screw, then used a carpenter's square to set it at 90 degrees, and put two more screws on each end. Then the second board goes on, three screws at each end.

I've been using some 2 1/2 "composite deck screws" I got at Home Depot. I like 'em because they are dipped in Rustoleum (less likely to rust and stain). They also have a square head, so your driver is less likely to slip off and strip them. I use a hefty variable-speed power drill, the kind you plug in. It takes an expensive portable drill to get the torque you need, and with the battery, it would be heavier.

I also picked up a few extra #2 square drive tips; they do lose their squareness after a while and can start slipping. They slip into a magnetic sleeve Stanley makes that goes into the drill chuck. Drive the screws down to where they dig into the wood a bit, they will be flush with the surface.

These boxes get pretty heavy to move around, so I built a small four foot square work table close to the garden, of of some free pallets. If you plan on building more than a few of these, you can tack some short pieces of 2x4 on the top as a template to position your posts, and save a little time.

Now here's the tricky part, it helps if you have a friend who can help hold things in position when you assemble the last two sides. If you're by yourself, lean one side up against your workbench. This should be one on a flat surface, so if you're out in the garden, put down a four foot square of plywood. First, position the side pieces. Even though the planks are 1x6, in reality they are more like 5 1/2 inches, so one corned is going to stick out a bit. Position them so the flush side is facing you, and the planks are on the outside. Lay a plank on top, roughly square it up, and drive a single screw in the center. Now use your square to get it nice and plumb, then drive the other two screws. Now go to the other end of the plank and repeat. Then put the second plank on. Beautiful!

Carefully turn the box 180 degrees, so the planks you just put on are down. Repeat what you did; first plank, square it off, screw it in, second plank. Be sure the planks on both sides all meet the top of the post. The other end, with a little bit of post sticking out, goes down in the dirt; you'll never notice it.

Now haul them off to the garden, carefully positioning them so you'll have a four foot path between them for the wheelbarrow. Fill them with a soil mixture. I use screened dirt, composted vegetation, and composed horse manure mixed with rice hulls. You can adjust draining and retention with pearlite and sand, if needed. The trick is constantly having your own compost piles, and shredding up all your organic waste. If there are folks with horses in your area, most of them are happy to give you all the manure you want, and you can get it delivered much cheaper than buying it by the sack at the garden center. Just be sure to let it set for a few months to cold down and turn to compost.

Materials list for two raised beds:

1 - Eight foot 4x4 post, fir or redwood.

8 - Six foot 1x6 dogeared redwood fence planks

1 pound 2 1/2" deck screws (they give you a driver tip, but pick up some extras)

When you get the posts, have them cut them into two four foot sections (no charge), easier to transport.

If you plan on making a lot of these, get 5 pound boxes of deck screes, you save about 30%.

You'll also need a saw, a drill, a collar for the driver tips, a square, and something to mark with.

I was able to build eight of these in about 2 1/2 hours, cost per bed was $17.