Back when we lived in Connecticut, I watched in horror as termites reduced my daughters' sandbox to a dusty mess in only two years. When it came time to build some raised beds in our new yard, it was essential to do something to protect the wood without putting nasty chemicals into the ground. Treated lumber still seems like a bad idea and I avoid it whenever possible.
To make the bed pictured here (better picture here) requires two 2 x 10 x 16 boards, 32 2.5 inch galvanized bolts, and about six feet of 4" PVC pipe (~$45). Prefab metal corners are fine for lower beds, but not real practical for a bed pushing 18" high. In the past, I've used 4 x 4 posts in the corners, but that just eats up space and gives the termites the mother lode if they crack your defenses. They're heavy and expensive, too, and finding scrap lengths of PVC is easy. Here's how I made it:
- Had the lumber yard cut the 16' boards into two 5' and two 3' lengths. This makes a 3 x 5 bed about 18 inches high.
- Added the thickness of the wood to half the width of the pipe, and drilled two holes on each end of the boards for the bolts, placing them off-center so I'd be able to reach into the pipe with my hand to get the nut on the bolt. Unless you have dainty hands, place the holes very carefully.
- Used a BioShield natural oil product to seal the wood. It's great stuff and easy to apply with just about anything.
- Cut four lengths of PVC to a height slightly lower than the bed. Drilled holes in them using the holes in the wood as pilots.
- Threaded all 32 bolts into place and tightened them.