Build Your Own Garden Beds

With spring around the corner, I’m thinking of my family’s garden and our plans to add new garden beds. I’ve built many different garden beds over the years, trying to strike a balance between an elegant design and simple construction. I thought I would share my favorite design and some tips along the way.

In my mind, a good garden bed design fulfills three important criteria: it’s functional, simple to construct, and pretty. A raised bed should reduce the need to bend over or kneel while gardening and should not be so wide that you cannot easily access the center of the bed. Garden beds need to be made from a simple, and relatively cheap construction because of their limited lifespan. And, because I want my yard to be an attractive space, the bed has to look good. I have designed this garden bed, with these factors in mind.

The box is constructed from 2 by 6 sides and 4 by 4 corner posts. An optional 2 by 6 trim board is added to cap the design. The following details will help you build a 4ft by 8ft bed, but the design can be easily customized to accommodate your space. You will need a measuring tape, a pencil, a drill, a speed square, and a circular saw or miter saw. Additionally, a set of sawhorses will make your life easier. The cheap plastic folding ones are my go to choice. The bed is built from ten 2 by 6’s and one 4 by 4, all in 8’ lengths.

Materials:

·         2 by 6 by 95” x 4

·         2 by 6 by 44” x 4

·         4 by 4 by 11” x 4

·         2 by 6 by 8’ (With 45o Miter Cut) x 2

·         2 by 6 by 4’ (With 45o Miter Cut) x 2

·         About 100 3” Coated Deck Screws

·         Exterior Construction Adhesive (Optional)

Material choice is important when it comes to building garden beds. There are three real options for wooden beds in the NW. Cedar, Pressure Treated Fir, and Untreated Fir. Cedar is the best choice if your budget will allow for it. It’s pretty, rot resistant, and easy to work with. You’ll want to buy tight knot cedar, often labeled TK, not the more expensive clear cedar for your garden beds from a local supplier. I recommend staying clear of big box stores as the material tends to be of lower quality. You may also consider pressure treated (PT) wood because it will last longer in contact with the soil than untreated wood. If you choose PT, make sure to purchase ground contact rated material as it will last a long time and it is relatively cheap. Before using PT, I would encourage you to do your own research on the topic and decide for yourself if that’s something you want in your garden. The chemical used to treat the wood can be harmful if ingested. But don’t worry, there is a third option, untreated fir. At about a third of the price of cedar, fir is non-toxic and will last nearly as long as cedar. It’s untreated, but for something that will need to be replaced regularly, a cheap material can be a good option.

Now that you have your material, it’s time to start building your bed. Keep your trim boards set aside for later and start cutting your side and corner material to length. More helpful tips on cutting material can be found at the end of this article. You will want to assemble your ends first and then add the longer sides. Place two 4 by 4 sections on a flat surface. Then set two end boards on top. Start by attaching to the board that will be placed at the top edge. Make sure that the top of the 4 by 4 is flush with the edge of the board. Put 2-3 screws through the face of the board into the 4 by 4 at each end. If you have trouble with the 4 by 4 shifting, try predrilling first. Then attach the other board in the same manner. Its edge should be flush with the bottom of the 4 by 4, but if it’s long, that’s not a problem because this will be the bottom edge. If it comes short, you can add a small gap between the boards. Repeat for the other end.

Now attach your longer sides to the end assemblies. Start by attaching the top board, keeping it flush to the top edge and end of your assembly. Screw thought the face into the 4 by 4. Like the ends, attach the bottom board next. Do this for both sides. At this point you have the main section of your garden bed built. You may want to set it in place now or install the top trim now depending on your situation, and where the beds are going.

Next, square your box. Take diagonal measurements, outside corner to outside conner. Your box is square when both diagonals measure the same. This will ensure that your 45-degree miters sit nicely. Now cut your trim material to length. The cut list should be correct for your boxes, but if they came out a little off, simply measure the length and width of the box and add an inch. This will give you the long measurement for your trim. It’s always easier to measure to the point instead of the obtuse edge of an angled cut. Now install the trim. It should overhang the side by half an inch, but the obtuse inner corners should also line up with the inside edge of the 4 by 4 corner posts if that is easier to line up. As an optional step to attach your trim more securely, add a quarter inch bead of construction adhesive, like Liquid Nails subfloor adhesive, to the top edge of the bed. Then screw through the trim, into the top of the 4 by 4’s and into the sides about every foot. Congratulations, you have built a garden bed.

Now set your bed in place. If the ground is especially uneven it may be necessary to dig a small trench for it to sit in. This is easier than leveling the whole area. If you want, you can also add weed cloth to the inside of the beds. This can be secured effectively with t50 staples. My mother, who’s an expert gardener, recommends filling your garden beds with a planting mix or 4-way mix from your local landscape supplier.

Modifying the Design

            As great as these garden beds are, you may want to make your own changes. These beds can be made taller, longer, or smaller. Here are some things you may want to watch out for. If you make your beds longer, add another 4 by 4 in the center of the long span to stiffen the side board connection. When changing the height, take into consideration that 2 by 6 material is 5 ½” wide. Atler your design by adding this amount, or maybe instead, add a 2 by 4 band in the center for a smaller adjustment. If you’re altering the length, keep in mind the availability of materials. 8’, 10’ , 12’, 16’ length are readily available. Your top trim needs to be an inch longer than your sides to overhang nicely. I recommend keeping these details in mind as you make alterations.