When we first moved into our home twelve years ago, I created a large fenced area for our veggie garden – 100′ x 50′ – and built raised beds out of 12″ boards and 4″x4″ corner posts for veggies and flowers. Even pressure treated wood doesn’t last forever, though, and by this spring, the beds were all but falling apart. On the spur of the moment, I decided to rebuild all of the beds before planting this spring.
The first step was to demo out all of the old beds – no small trick, since the dirt has to be shoveled out and set aside and the beds broken apart and disposed of. I decided on a different layout for the new beds, so all of the irrigation had to be rerouted, as well.
I wanted to build more durable, larger raised beds, so that they wouldn’t rot out quickly and I wouldn’t have to bend over so far. I decided to use pressure treated lumber for the frame and galvanized metal for the sides. I built 12 beds 4’x8′ and 2′ tall. For each bed, here are the supplies you’ll need:
* Six 8′ 2×4 boards (cut two of these boards in 4′ lengths, so you have four 4′ lengths and four 8′ lengths)
* Three sheets of 8’x2′ galvanized metal (these are available at Home Depot) (cut one sheet in half so you have two 8′ sheets and two 4′ sheets)
* One 12′ 4×4 post (cut into six two-foot pieces)
* One 12′ 2×4 board (or two 6′ 2×4 boards) (cut into eight pieces, each 16.5″ long)
* One 4’x8′ sheet of wire mesh
* Roofing screws
* Metal screws
Tools are, as I find for almost all projects, a key to making this project uncomplicated and professional-looking. You’ll need a chop saw (or something similar) to make all of the wood cuts, a rotary saw that’s designed for cutting metal to cut the galvanized sheets (we had to buy one at Home Depot, the cost was a little over $100), and a good drill with the right attachments for screwing in the wood and metal screws. Safety is also an important factor – you will definitely want safety glasses when using the saws, particularly the metal saw because it throws up little metal pieces, and we also used ear plugs when cutting the metal because of the screeching noise. One note: the Home Depot sign said that the metal sheets were 24″ wide, but when we got them home, they were at least 6″ wider (go figure), so we had to cut them lengthwise, as well as cut some of them in half.
1. Cut all of your materials to the dimensions listed above (see information on tools and safety).
2. Create the frames for the two long sides – lay down three 4×4 posts, approx 45″ apart. Place two of the 8′ 2x4s over the top and bottom of these posts. Use a square to make sure that your corners are all square; use the drill to screw in two wood screws per corner, and two each at the top and bottom of the middle 4×4. Repeat for the second long side.
3. Lay one of the 8′ metal sheets on top of the completed long side frame – if you have a sharper cut edge (as we did, since we had to cut off some lengthwise), make sure that’s at what will be the bottom of your frame (it’s okay if this extends a little beyond the frame, because it will be in the ground). Line up the metal approx 1″ below what will be the top of the frame, so that the metal doesn’t come right up to the top of the wood (you don’t want any chance of cutting yourself on the sharp metal edge when you’re working in the veggie box). Use the drill to screw in the metal screws (four on the top, equally spaced, and the same on the bottom). Repeat for the second long side.
4. Have someone hold the two long sides on their ends, parallel to each other and approx 4′ apart (just as they will be when the box is finished), making sure that the length you designated as “bottom” is on the ground for both sides. Use the drill to attach the two 4′ 2x4s to the top and the bottom on each end of the frame (two screws in each corner).
5. Take four of your 16.5″ 2x4s and slide them into the gap between the metal and the end of the long frame on all four corners (this is necessary because otherwise there will be a gap here when the box is completed). If you need to trim them down a little in order to get them to slide into place, go ahead and do so. Use metal screws to attach the long ends of the metal to these “gap-fillers” (don’t worry that the gap-filler isn’t screwed to the wood frame, this won’t matter).
6. Take the remaining four 16.5-inch 2x4s – line them up on the inside of the 4×4 posts on each end of the frame (so that they cover the gap-fillers you just screwed in). Again, you may need to trim them down just a little bit in order to get them to fit between the top and bottom frame boards. Attach these by using a wood screw to screw these pieces into the gap fillers (this will cover the gaps that would otherwise exist between the frame and the short metal sides).
5. Slide the 4′ piece of galvanized metal on the inside of the box on the short end and push it into place (you may have to pound on it a little with your hand to get it to push in flush with the 2×4 frame – don’t worry, any dents can be pounded out afterwards). Remember to line up the top end about 1″ lower than the top of the bed. Screw in place with two metal screws on each side.
6. We just laid the 4’x8′ wire mesh sheet in the bottom of each box, but if you want, you could attach it with staples (you’d need to flip the box over to do this, and the wire mesh sheet would have to be slightly larger than 4’x8′ so that there was some overlap onto the edges of the box). You may not find this step necessary, but on our farm, as many pests (like voles) come up through the soil from underneath, as climb into the beds over the top!
The great thing about these beds is that they’re tall enough so that you can garden in them without bending over much. Also, their height keeps out some of the things that eat the crops (like rabbits), along we find that the mice and other rodents still climb right on up (sigh). You’ll need 64 cubic feet of soil to fill each bed; make sure that you purchase soil that is specifically meant for filling garden beds (NOT compost alone, or just mulch, or potting soil). Because we needed so much soil to fill all of our beds, we ordered it delivered from Valley Landscaping, a local company that had the perfect three-way blended topsoil (a mix of soil, compost, and sandy loam).
In addition to twelve 4’x8′ beds, we also built four 2’x8′ beds – they may look a little strange because they’re so narrow, but I set them approx six feet apart and then used 2x4s and 4’x8′ sheets of cattle fencing to build these trellises:
I can’t wait to grow climbing beans, peas, and other veggies on these trellises this summer – by the time they’re entirely covered with vines, it will make a tunnel of greenery!
The photo example I used as the inspiration for these boards had countersunk the 2×4 framing boards into the 4×4 posts – if you did that, you wouldn’t need the gap-filler boards in steps #5 and #6 (something we didn’t figure out until we got to those steps and had to think creatively to address the gaps we hadn’t anticipated!) However, making the cuts for the countersinking would be complicated – in my mind, more difficult than using the gap-filler boards. And, I don’t think that the extra framing does anything to detract from the box’s appearance.
My last step is going to be to using copper flashing to cover the tops of each of the 4×4 posts – this is both for appearance and practicality, as these exposed ends will rot out more quickly if they’re not protected.
If you’d like help building beds like these and you live in the Portland area, contact Casey Beatty with CMB Properties, LLC at (503) 310-0870.
ETA: In the spring of 2015, we capped the beds with 8″ boards to improve the appearance, eliminate any risk of the beds bowing out, and give us a nice place to lean while planting, weeding, or harvesting (see pics here).
ETA: In response to inquiries about how the metal and the pressure treated lumber is holding up, here’s how the boxes look this spring, five years later: