How to build a raised bed from discarded shipping pallets
Story and Photos by Sue Hughes
Planting a garden in raised beds has several advantages:
• Warms up faster in the spring
• Easier to weed and maintain
• Better control over the soil mixture (since you add it yourself)
• Improved drainage
• Prevents soil compaction
While you can purchase materials at a hardware store or even use a raised bed kit, you can also make your own for next to nothing using free shipping pallets! While most business owners are happy for you to cart some off, make sure you ask permission first.
These days, most pallets have been heat treated or fumigated with methyl bromide for pest control, as indicated by their marking. The standard is a 2-letter country code (xx), a unique number (000) assigned by the National Plant Protection Organization, and then HT for Heat Treatment or MB for Methyl Bromide, and DB to signify debarked.
While chemical treatments are good for pallets, they’re not good for plants so, for any pallet project intended for plants, provide a barrier between the pallet and the soil to prevent chemicals from leaching into the soil, and to prevent the pallet from decay. We used layers of cardboard and plastic as a barrier, but metal sheeting also works.
Keep in mind that the taller and longer your bed, the more media it takes to fill. You’ll need potting soil for at least the top 6 six inches, but below that you can fill your raised bed with any compostable materials: logs, branches, leaves, straw, shredded paper or newsprint, garden trash, and kitchen scraps – the more varied the mixture, the better.
For this raised bed, we used:
• 6 pallets
• Circular saw
• Wood screws
• Power drill
• 2 ft 4 x 4 lumber
• 18 ft 2 x 6 lumber (treated or untreated)
• Large cardboard boxes, flattened out (optional)
• Paint (if using untreated wood)
1. Cut pallets to the desired height of your raised bed. A raised bed should be at least 12 inches high, allowing plenty of room for roots, even if the raised bed sits atop concrete rather than earth. I like mine taller so I don’t have bend over or kneel, and I like to be able to sit on the raised bed’s ledge to do my work, so mine are 2-3 feet tall. For this project, we started with 40-by-48-inch pallets, and then cut the shorter side to 22 inches, retaining the center rib.
2. Arrange the pallets to your desired configuration. The length and width of your raised bed are up to you, but neither should be more than 4 feet, which would make it too hard to reach. Position the side with more planks on the inside of the bed. We made ours two pallets long and one pallet wide.
3. Join the pallets. To build the long sides, we butted two pallets together and joined them at the top and bottom using leftover pallet planks from the part we cut off. For the corner, we screwed the inside plank of the end piece (which was the top of the original pallet) into the side wall (the end from the original pallet).
4. Once all the sides are up, insulate the inside walls by stapling a layer of cardboard and then plastic. This step helps retain soil that would otherwise leak through the planks. It also prevents moisture from decaying the pallet wood, and isolates chemicals or pesticides in the pallet wood. The cardboard helps keep the plastic from ripping due to nails or the wood’s rough surface. We used cut up leaf bags for the plastic layer in this raised bed.
5. Add a railing to the top of the raised bed. For stability, ensure the rails on the long sides extend to the outside edge of each end wall. We used untreated lumber for this, which means we’ll have to paint this railing before considering it done. If you use pretreated lumber, or wood such as redwood, you can skip the paint. We added a 4×4 block to the end of ours to give us something for the rail to attach to.
6. If your raised bed is on grass, cover the grass with several layers of cardboard. Ensure the cardboard extends to under the sides of the bed. This deters grass and weeds from growing through and around the bed.