Building Raised Garden Beds

Landscaping for Small Yards

Raised flower bed
Ofer El-Hashahar / Flickr / CC By 2.0
  • 01 of 10

    Buying Lumber to Build a Portable Raised Bed

    These 1x3.5 boards will form the bottom or "floor" of the planting bed.
    David Beaulieu

    An oft-cited principle regarding construction in crowded areas is, if you can't build out, you have to build up. That same principle is, in part, the inspiration behind the present project for landscaping small yards. This tutorial deals with building raised beds in a portable "bench" style, which gives you a planting bed on top and a storage area below. This bed is easy to transport, but there are more conventional stationary garden beds as well. 

    Measurements and Buying Lumber for the Raised Bed

    The raised bed in this project stands 3 feet tall. But much of that height comes from the supporting legs. The planting bed itself has a depth of 14 inches. The raised bed is 5 feet long x 19 1/4 inches wide.

    Beyond needing 2 x 4s for framing, dimensions weren't important to us; we were shopping for price, and any boards with a 1 inch thickness (for the sides and bottom, and for the bottom shelf) would have been fine. We ended up with a mixture of widths: 1x3.5 and 1x6. That's just what happened to be in the "sale" bin. As you build your own raised bed, adjust your measurements accordingly, depending on the widths of your own lumber.

    Here's an approximation of the lumber that our project required, in terms of board feet:

    1. 39 board feet of 2x4s
    2. 6 board feet of 1x6s
    3. 50 board feet of 1x3.5s

    It's prudent to buy extra lumber, in case you make any mistakes during the cutting.

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  • 02 of 10

    Cuts for the Frame

    2x4s are cut to length and used to form the frame
    David Beaulieu

    Another advantage of the "bench" style of raised beds is that they're high enough to eliminate bending over altogether while you garden, a point that won't be lost on those who suffer from bad backs. In addition, installing a caster on each leg of the raised bed makes it portable.

    But the benefits of this style of raised bed don't stop there. Many of us landscaping for small spaces live in the city, also known as "the asphalt jungle." And asphalt simply isn't friendly to plant-lovers. The raised bed that we built for this tutorial dwells on asphalt, near the back door of an urban home. No other style of raised bed would make sense in such a location.

    Supplies Needed

    • Drill and attachments
    • Saw
    • Tape Measure
    • Screws
    • Paint and brush
    • Landscape fabric
    • Staple gun and staples
    • Lag bolts and ratchet wrench
    • 4 Casters
    • 4 finials (optional)

    Let the Cutting Begin

    Selecting boards from your 2x4 pile, cut 2 of them to a length of 3 inches, and cut two others to a length of 16 inches (see photo). The former will be the legs for one side of the raised bed; the latter will be the braces, which will join the legs together, forming a framing unit. Repeat this process for the other side of the raised bed.

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  • 03 of 10

    Bracing the Legs of the Raised Bed

    Brace being screwed to leg, using a drill
    David Beaulieu

    The raised bed in this project stands 3 feet tall. But remember, much of that height comes from the supporting legs. The planting bed itself has a depth of 14 inches. That means the top of the "floor" will lie 14 inches down from the top of the 2x4 frame. It is here, in Step #3, that you make that measurement and establish where the bottom of the planting bed will be.

    The floor will be comprised of 1x3.5 boards. You want the tops of those boards to lie 14 inches from the top of the frame. The floorboards will be supported by braces spanning the legs. To achieve the correct height, then, measure down 15 inches from the top of a 2x4. Mark the measurement. This is where the brace will be attached to the leg.

    Place the brace (one of the 16 inch 2x4s you cut) perpendicular to the ground. Now place the leg (one of the 3 foot 2x4s you cut) atop it, forming a "T" shape. The intersection will be where you made your mark. Using the drill, pre-drill a hole through the leg and into the brace.

    Again using the drill, join the leg and brace with a screw.

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  • 04 of 10

    Raised Bed Shelving

    The 2 legs for one side of the raised bed, joined by 2 braces
    David Beaulieu

    The brace on the prior page will support the floor for the planting bed. But now we'll attach a brace that will support the shelving under the planting bed.

    Measuring from the opposite end of the 2x4 leg now, measure up four inches. Mark it. Next repeat the process undertaken on the prior page (pre-drilling and screwing), attaching a second brace to the leg.

    Now position the second leg, so that you can attach it to the braces in the same fashion (pre-drilling and screwing). The result is shown in the photo above. You now have a solid framing unit, composed of four 2x4s joined together. Repeat the process for the other side of the raised bed. You are well on your way to finishing the frame for this project. 

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  • 05 of 10

    Installing the Floor

    The flooring for the planting bed spans the framing units
    David Beaulieu

    You now have two framing units, one for each end of the raised bed. Next, cut four 1x3.5 boards to a length of 5 feet. Set the framing units upright, 5 feet apart (propping them up with watering pails or anything you have handy).

    Lay the 1x3.5 boards across the framing units, spanning them. Space them slightly, to provide drainage and aeration. Work out from the center, as you'll want to leave 2 inches free at the sides (enough room to fit the 2x4 you'll be using in Step #8). Pre-drill holes through them and screw them into the supporting 2x4 braces in the framing units.

    You now have the "floor" or bottom of the planting bed. In Step #6 we begin on the walls.

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  • 06 of 10

    Installing the Ends of the Raised Bed

    Attaching one of the short walls of the raised bed
    David Beaulieu

    Raised beds have four walls. In this project, the raised bed is a long rectangle. So there will be two long sides and two short sides. Let's call the latter "ends," to distinguish them from the former.

    The photo above shows what one of the ends looks like. We used our 1x6 boards here. Again, the boards are spaced slightly apart, to promote aeration. Pre-drill first to avoid splitting the boards, then screw them in. Repeat on the other end.

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  • 07 of 10

    Installing the Long Sides of the Raised Bed

    1x3.5 boards are screwed onto the frame to form the sides of the raised bed
    David Beaulieu

    The photo above shows the raised bed after one of the longer sides has been installed. We used more of the 1x3.5 boards here (same dimensions as the floorboards). Again, the boards are spaced slightly apart, to promote aeration. Pre-drill first to avoid splitting the boards, then screw them in. Repeat on the other side.

    Note in the photo above that we've begun to install finials atop the framing units. Finials are optional, but they do dress up raised beds.

    Note also in the photo that we've begun to install boards to complete the shelf, on the lower part of the raised bed. The shelf boards need be only 17.5 inches long, so this is a good chance to use up any leftover 1x6 or 1x3.5 lumber, from the cutting you've done in prior steps.

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  • 08 of 10

    Installing More Braces for the Raised Bed

    The 2x4 with the "X" on it is toenailed into the frame, for added bracing.
    David Beaulieu

    At some point before completing your raised bed, you'll want to provide further braces. This is as good a place to discuss it as any, although you could have installed the additional bracing as early as Step #5 (right after finishing the framing units).

    The bracing that I'm referring to will serve two functions. First of all, it will solidify the framing units. Secondly, it will provide support for the flooring. The latter is especially helpful since the amount of soil in a planting bed of this size will weigh a significant amount.

    Begin by holding a 53 inch 2x4 parallel to the floorboards and toenailing it into the legs, spanning the length of the structure (see photo). Repeat on the opposite side.

    To proceed with this step in the easiest possible way, it's probably best to flip the raised bed upside-down at this point. Now attach three evenly-spaced 16-inch cross-braces (also 2x4s) to the two boards you just toenailed in, spanning them. The attaching can be done with lag bolts (using a ratchet wrench), which afford extra stability. In fact, now that you're finishing up, it wouldn't hurt to go back and throw a few lag bolts into some other key areas of the framing.

    While you've got the raised bed upside-down, install a caster on each of the four legs. The bigger the caster, the more weight you'll be able to move around.

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  • 09 of 10

    Paint the Raised Bed and Staple Landscape Fabric on the Inside

    Staple landscape fabric on the inside of the planting bed, to retain the soil
    David Beaulieu

    You can breathe a sigh of relief: the carpentry-phase of the project is over! The current step involves painting, then lining the inside of the planting bed.

    First, paint the entire raised bed, unless you'll be planting it with edibles. We'll be planting flowers in our raised bed, so we decided to apply paint. A coat of paint will help preserve raised beds, which will, after all, be subjected to a lot of moisture. We used a latex paint.

    Next, staple landscape fabric to the inside of the planting bed, to retain the soil. You'll probably have to overlap a few strips of landscape fabric to achieve complete coverage. We ran a strip of landscape fabric along the length of the planting bed first and stapled it (fold and staple in the corners as neatly as you can). Then we ran one strip perpendicular to this, to cover the left side of the planting bed, followed by another to cover the right side, stapling both in place.

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  • 10 of 10

    The Finished Raised Flower Bed

    The finished raised bed, filled with soil and planted with flowers
    David Beaulieu

    With the floor lined with landscape fabric, you're ready to add soil to the raised flower bed. The planting bed area has a depth of 14". That's a lot of space to fill, so you'll want to mix generous amounts of peat moss, perlite, or vermiculite into the soil that you're using. Any of the three will lighten your soil, allowing it to breathe better. Peat moss, perlite, and vermiculite also help your soil retain moisture.

    Perhaps you're wondering, "Why build a raised flower bed with such a deep planting area?" If you've ever had a container garden (which this raised bed could be classified as), you may already be able to guess at the answer. The soil in most container gardens has a tendency to dry out too quickly. That's because their soil lacks sufficient mass. As a result, you end up having to water frequently, which may be inconvenient for you. But the 14" depth of our raised flower bed affords us a soil mass that will retain water well.

    We had old styrofoam around and decided to recycle it as filler. I'd avoid using it in a planting bed for growing vegetables, but the structure for us is purely a raised flower bed. We broke up the styrofoam and put it down for a first layer, where it will provide good drainage and aeration.

    We then filled our raised flower bed with soil, which was mixed with peat moss to lighten it and with compost to enrichen it. As you can see from the photo above, we wasted no time planting in our new raised flower bed!