How To Build Tall Raised Beds For Your Garden
Make gardening easier on your back and give roots more room to grow.
By Oscar H. Will III
So you’ve heard or read about the advantages raised beds offer to organize and tend your garden, but why not raise them high enough to keep the aches and pains at bay? Some tall raised beds are set up on posts or legs, but we suggest that you build your containers right on the soil to avoid the need for a superstructure that could fail. Plus, your plants get to be in contact with native soil, and your deep-rooted vegetables won’t get cramped roots!
You can build your beds about any size you wish. Our plan calls for roughly 3- x 5-foot dimensions with a depth of 30 inches, but feel free to modify based on the most efficient use of the material you source. We chose Douglas fir—untreated, since we’re growing food—because it has fair rot resistance above-ground, is easily obtainable and relatively inexpensive. If a six- to seven-year lifespan is not sufficient for you, then you might opt for Western red cedar, which can last for as long as 10 to 15 years.
- Using your tractor’s loader and/or grader blade, create a level area for your bed(s). Leave at least 3 feet between the beds for pathways, and plan ahead so you can expand to more beds in the future.
- Cut your boards to the lengths indicated in the materials list or to suit your modification of this plan.
- With a helper, stand two of the 3-foot lengths of 2 x 8 vertically, and place a 5-foot length of 2 x 8 across the top of them, aligning the ends. Using your drill, drive two screws through each end of the 5-foot 2 x 8 and into the end grain of the vertical 3-footers.
- Carefully flip the structure over so it resembles a “U,” and set another 5-foot 2 x 8 across the two vertical boards. You might need to rack or twist the structure slightly to get the ends to line up. Screw the 5-footer in place as above.
- Carefully lay the rectangle down and square it up, measuring the distance diagonally from corner to corner in both directions. When the distance is the same, the rectangle is square.
- Stand a 3-foot length of 2 x 4 in one of the corners of your rectangle so the long (4-inch nominal) dimension is flat against the 3-foot side and the edge is against the 5-foot side. Secure the 2 x 4 with at least three screws from the outside of the box into the edge of the 2 x 4 and three into the flat side of the 2 x 4, being sure to avoid existing screws!
- Repeat step 6 with the other three corners of the rectangle.
- Repeat steps 3 and 4 to make a second rectangle, and carefully drop it over the exposed ends of the 2 x 4s, then screw into place. The 2 x 4 will help square up the second layer; don’t be afraid to use a hammer to get it all to fit.
- Repeat steps 3, 4 and 8 to create the remaining two layers of the box. You should now have a box with sides about 30 inches tall, an outside length of 5 feet and an outside width of about 39 inches (36 plus the thickness of the side boards times two). Use the remaining
2 x 4 extending above each corner as a support for trellises or row-cover frames, or to locate another rectangle layer of sides to make it taller.
- Flip the box upside down and, using a pneumatic or manual staple gun, fasten the hardware cloth to the bottom of the box using two lengths of 36-inch-wide material about 39 inches long, overlapping the excess in the middle. The purpose of the hardware cloth is to keep moles and rodents from burrowing up into your raised bed from below, yet still allowing roots to grow down into the soil below.
- Set the box, hardware cloth side down, in your garden, and fill to the top with your favorite compost or garden soil mix. Pure topsoil should be avoided. (We use 2-year-old compost.)
Treat your raised bed as you would any garden, and don’t forget to trellis or cage vegetables that require support. Don’t be afraid to plant more densely in these beds since you can so easily weed and thin. You can also connect an irrigation system to your beds and make it your easiest gardening season ever.
You can haul materials or level off a spot for your garden projects with a Massey Ferguson GC1700 Series tractor and loader. Yet, you’ll find 100-plus other uses for it too, like mowing the lawn, tilling a spot for the rest of the garden, smoothing out the driveway or moving snow in the winter.