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Building your own elevated garden bed is a simple and rewarding project. First, choose a suitable location with plenty of sunlight. Then, gather materials such as wood or cinder blocks to create the frame. Assemble the frame, ensuring it is sturdy and level. Next, fill the bed with a mixture of quality soil and compost. This will provide a fertile environment for your plants to thrive. Finally, choose the appropriate plants for your garden bed and start planting! Regular watering and maintenance will ensure a successful and bountiful harvest. Enjoy the benefits of fresh homegrown produce from your very own elevated garden bed.
Raised garden beds have numerous benefits, even if they are placed at ground level. However, these advantages increase when you build an elevated garden bed that places the soil level at waist height or higher. This is particularly beneficial for older gardeners or individuals with physical limitations, as it eliminates the need to stoop while gardening. Whether you’re planting herbs, vegetables, or perennials, this method of gardening is more enjoyable and rewarding. Additionally, raised beds allow you to use a customized growing medium that is free from weed seeds and pathogens commonly found in regular garden soil.
Instead of purchasing a pre-made elevated garden bed, which can be quite expensive, it is possible to build your own DIY version. The materials required for this project cost significantly less, and the end result is a sturdy and durable bed.
Understanding the Design
This design utilizes standard 2x cedar lumber for most of the construction, which can be easily obtained from any major home improvement store. The design is straightforward, making it perfect for beginners in woodworking, and the dimensions can be adjusted to create a larger or smaller elevated garden bed.
The elevated planter is essentially a basic box made of 2×6 and 2×4 cedar lumber attached horizontally to four vertical 4×4 cedar posts. This forms an elevated planter with the top roughly at waist level. For a more decorative appearance, the edges of the cedar side boards can be rounded using a router before attaching them to the posts.
At the bottom of the box, three joists made of cedar 2×4 lumber span the width, providing support for a floor made of 5/4 x 6 cedar planks. This floor, supported by the joists, offers ample strength to hold the potting mix, even when saturated with water.
This DIY design has a significant advantage over many commercial elevated planters. Commercial planters often use narrow cleats on the inside of the box to hold the floor, which is not sturdy enough to support water-saturated soil. This can lead to the planter collapsing under the weight. It is disappointing to spend a large sum of money on a raised planter only for it to fail.
The dimensions provided in this guide will result in an elevated planter bed that is approximately 3 feet wide and 4 feet long, with the top of the planter standing at around 4 feet above the ground. If you decide to alter the dimensions, it is recommended to create simple sketches of the side, end, and top views of the planter to accurately determine your own measurements. For wheelchair-bound gardeners, a height of 24 to 30 inches is ideal for the elevated bed.
Important Information about Wood
A raised garden bed is commonly constructed using pressure-treated pine lumber, which is known for its durability. Some gardening experts advise against using lumber treated with pesticides for planters that will grow edible plants, as they are concerned that the toxins may be absorbed by the plant roots. However, modern pressure-treated lumber no longer contains the highly toxic chromate copper arsenate that was once used. Today’s pressure-treated lumber is considered safe for growing edibles, although it may be a good idea to line the inside of a pressure-treated planter box with heavy-grade plastic sheeting for added safety.
This particular planter is made from cedar lumber, which naturally resists pests and decay. It is an excellent choice for a vegetable garden or for growing your own food. The inside of the box is coated with a water-based penetrating sealer, and synthetic landscape fabric is used as an inner liner to prevent soil from leaking out through cracks and drainage holes.
Materials You Will Need
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(4) cedar 4×4 posts, each measuring 4 1/2 feet long
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(4) cedar 2×6 side boards, each measuring 4 feet long
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(4) cedar 2×6 end boards, each measuring 3 feet long
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(2) cedar 2×4 side boards, each measuring 4 feet long
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(2) cedar 2×4 end boards, each measuring 3 feet long
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(3) cedar 2×4 floor joists, each measuring 33 inches long
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(6) cedar 5/4 x 6 decking boards, each measuring 36 inches long
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1/4 x 3-inch Torx-drive zinc-coated lag screws with washer heads
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(6) galvanized joist hangers for 2×4 joists
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1 1/2-inch metal connector nails
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Clear water-based wood sealer
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(4) cedar post caps (optional)
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Synthetic landscape fabric
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General-purpose potting mix
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Tape measure
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Circular saw or power miter saw
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Router (optional)
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Hammer
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Drill with spade bit
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Jigsaw
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Paintbrush
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Utility knife
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Utility stapler
Image Credit:
Wayfair
How to Construct a Raised Garden Bed
This list provides the final measurements for the components that will be used to build the raised garden bed. It is recommended to purchase lumber in standard 8- or 12-foot lengths and then cut the necessary pieces from those boards. For instance, all four 3-foot-long boards can be cut from a single 12-foot-long board, and the four 4-foot-long boards can be cut from two 8-foot boards. However, if desired, most home centers offer lumber cutting services for a small fee.
Step 1: Cut the Pieces for the Planter Box
If you have purchased lumber in standard lengths, use a circular saw or power miter saw to measure and cut the posts, side boards, and end boards to the desired length. Do not cut the floor joists or 5/4-inch flooring boards yet; wait until the rest of the box is built to measure and cut these pieces to fit.
If desired, you can use a router to round over the top and bottom edges of each side and end board, giving the planter walls a more decorative appearance.
Step 2: Connect the Side Boards to the Posts
Place two of the 4 1/2-foot posts horizontally on a working surface and then position and attach a 4-foot-long 2×6 side board, followed by a 2×4 side board, and then another 2×6 board so that they align with each other as they extend across the posts. The side boards can be level with the tops of the posts or slightly lower if you plan to add decorative caps to the posts. The ends of these side boards should be perfectly aligned with the outer edges of the posts.
Secure each side board to the posts using Torx-drive lag screws and a power drill. If desired, you can first create counterbore holes to recess the screw heads below the surface of the boards. The bottom boards will bear a significant amount of weight, so they should be anchored with three lag screws at each end, driven into the posts.
Repeat the process with the other two posts and three additional side boards. You now have two side assemblies that are ready to be connected to the end boards to complete the basic structure of your planter.
Step 3: Connect the End Boards
Stand the side assemblies upright and position them 3 feet apart. You can use an assistant or secure a brace made of scrap wood across the tops of the posts to keep the assemblies upright.
Attach a 3-foot-long 2×6, followed by a 2×4, and then another 2×6 to the front face of the posts at each end of the planter. Ensure that the ends of the boards cover the end grain of the side boards and are flush at the corners. Use a pair of screws at each end to join these end boards to the posts, following the same method used for attaching the side boards.
You should now have a basic structure elevated by corner posts that run through the inside corners of the planter.
Step 4: Install the Joist Hangers
Attach three evenly spaced joist hangers on each side of the inner surfaces of the bottom side boards. The bottom edges of the joist hangers should be level with the bottom of the side boards. Place the outer joist hangers next to the posts, with the third joist hanger positioned in the exact center of the planter. Use 1 1/2-inch metal connector nails to secure the hangers to the inner surfaces of the side boards.
Step 5: Attach the Joists
Measure and cut three 2×4 cedar joists to span the width of the planter. Insert each joist into a pair of opposite joist hangers and fasten them with joist-hanger nails.
If you have constructed a significantly larger elevated garden bed, you may need to install additional joists for better support. Ideally, the joists should be spaced no more than about 16 to 18 inches apart. For example, a 5- or 6-foot-long planter should have at least four joists.
Step 6: Cut and Install the Floor Boards
Cut six 5/4-inch cedar decking planks to fit the length of the floor, placing them on the joists from one end of the planter to the other. (A larger planter box will require more floor boards.) Use a jigsaw to notch the outer floor planks to fit around the corner posts.
Check the fit of the flooring boards. If there are small gaps between the boards, that’s okay because it allows excess water to drain through the planter box. However, if the seams between the boards are very tight, you’ll need to drill two or three 1/2-inch drainage holes in each board.
There’s no need to permanently attach the flooring boards to the joists. They can simply rest on the joists, making it easier to remove the boards for future maintenance or replacement.
Step 7: Apply a Water-Based Sealer to the Wood
Use a paintbrush to apply a water-based sealer to the wood. It may be easier to temporarily remove the floor boards for this step. While not necessary, sealing the wood will prolong the lifespan of your elevated garden bed. Some gardeners prefer to remove the soil from the planter box after each planting season to clean and reseal the wood for the next season, a maintenance routine that can extend the life of a cedar planter for many years.
If desired, you can also stain the exposed outside surfaces of the elevated planter with a color of your choice. However, it’s best not to stain the inside of the box. Instead, use a nontoxic water-based sealer for the inside surfaces.
Step 8: Add Decorative Post Caps (Optional)
If you’d like, you can add decorative post caps to the tops of the four corner posts. If you’re using cedar caps, seal them with a clear wood sealer before attaching them. This is a good choice if your planter is built in such a way that the posts extend above the sides of the box, but it’s not necessary if the posts are flush with the top edges of the box. Post caps can be nailed in place or secured with outdoor adhesive.
Step 9: Install a Liner
Cut a piece of synthetic landscape fabric that is larger than the planter box and attach it to the inside faces of the box using a utility stapler. The corners of the fabric should be folded tightly into the corners to match the shape of the box, but it doesn’t have to fit perfectly. This liner will protect the wood and prevent potting soil from falling through cracks or drainage holes in the floor of the planter box.
If you used pressure-treated lumber for your planter, it’s best to line it with heavy plastic to ensure that no chemicals leach into the soil and are absorbed by plant roots. However, the plastic liner will need drainage holes punched in it.
Step 10: Add Growing Mix
Finish your DIY raised garden bed by moving it to your desired location in the yard and filling it with a growing medium of your choice. A general-purpose potting mix is suitable, but you can also save money by making your own mix using equal parts of peat moss, vermiculite or perlite, compost, and sterilized topsoil. If desired, you can also add some granular time-release fertilizer.
Like any container garden, it’s best not to use ordinary garden soil in your elevated garden bed, as it may contain weed seeds and pathogens that can be problematic in a planter box. Using a purchased or DIY potting mix is a better option for successfully growing plants in an elevated garden bed.
