How to Build a Cedar Raised Garden Bed from Boards and Posts
By Greenes Fence Company: Cedar Raised Garden Beds ... | Published: 2026-10-19
Category: How-to Guides
Learn to build a cedar raised garden bed using boards and posts. Step-by-step assembly, height options, and tips for a sturdy, long-lasting bed.
Quick Answer
Build a cedar raised garden bed by connecting cedar boards with short or tall posts, stacking layers for height, and securing the structure on level ground.
Why Cedar Boards and Posts Work Well Together
Cedar boards and posts are designed to fit together simply: boards slide into the slots of the posts, and posts stack to add height. This modular system lets you customize the size and depth of your bed without cutting or special tools.
The 4 ft cedar board is the longest option available, making it ideal for building longer beds or expanding an existing one. Shorter boards can be used for smaller beds or to create corners and dividers.
Because the posts stack on top of each other, you can add height in 7-inch or 11-inch increments. This is useful for deep-rooted vegetables or for gardeners who prefer a raised bed that is easier on the back.
All cedar is naturally rot-resistant and untreated, so it is safe for growing edible plants. You can leave it to weather naturally or stain it to match your garden style.
Choosing the Right Height for Your Bed
The height of your raised bed affects both the plants you can grow and the amount of soil you need. A single layer of boards (3.5 inches) is quite low and may not be sufficient for most vegetables. Adding layers increases the depth, which is better for root growth and moisture retention.
If you plan to grow root crops like carrots or potatoes, aim for at least 11 inches of soil depth. Using tall posts (12 inches) with two 5.5-inch boards gives you 11 inches per layer. For even deeper beds, stack additional layers.
Keep in mind that taller beds require more soil, which can add cost. If you want to save soil, consider filling the bottom with organic material like logs or leaves before adding topsoil.
For accessibility, a bed that is 24 to 36 inches tall reduces bending and is easier to tend. You can achieve this by stacking multiple layers of boards and posts.
Step-by-Step Assembly
- Plan your bed dimensions: Decide the length, width, and height of your bed. For a standard bed, use 4-foot boards and choose short or tall posts based on desired depth. Sketch a simple diagram to visualize the layout. Common mistake: not leveling the ground beforehand—this causes wobbly posts and gaps.
- Prepare the site: Clear the area of grass and weeds, then level the ground as much as possible. Use a rake or shovel to remove high spots. If the area is very uneven, consider building a wooden frame base. Checkpoint: use a carpenter's level to ensure the base is even before assembly.
- Insert boards into posts: Slide the ends of the boards into the slots of the posts. For a rectangle, place a post at each corner and slide the boards into the slots. Ensure the boards are fully seated and the posts are upright. Common mistake: forcing boards into slots—if they don't fit, align them correctly and tap gently with a rubber mallet.
- Stack additional layers for height: If you want a deeper bed, place another post on top of the existing one and insert the next layer of boards. Tall posts add 11 inches per layer, short posts add 7 inches. Continue until you reach your desired height. Checkpoint: ensure each post is aligned vertically to keep the walls straight.
- Secure the structure: Use stakes or corner braces to anchor the bed to the ground, especially for taller beds. This prevents shifting during heavy rain or wind. You can also use screws to reinforce the joints, though the posts are designed to hold boards securely. Common mistake: skipping anchoring—tall beds can lean over time without support.
- Fill with soil and plant: Fill the bed with quality garden soil, leaving about an inch from the top. Water thoroughly and let it settle, then add more soil if needed. Plant your vegetables or flowers according to their spacing requirements. Checkpoint: test soil drainage by watering and observing how quickly it absorbs—adjust if needed.
Cedar Boards and Posts at a Glance
- Premium Cedar Tall Post 12 in x 2.5 in x 2.5 in RCTP: The Premium Cedar Tall Post is 12 inches high and holds two 5.5-inch boards, adding 11 inches of height per layer. Posts stack for quick expansion. Use tall posts when you want a deeper bed without extra assembly steps—each layer adds significant growing depth.
Premium Cedar Tall Post 12 in x 2.5 in x 2.5 in RCTP - Premium Cedar Short Post 8 in x 2.5 in x 2.5 in RCS: The Premium Cedar Short Post is 8 inches high and holds two 3.5-inch boards, adding 7 inches of height per layer. It stacks on tall posts as well. Short posts offer a lower-profile option for beds that need less depth or for creating tiered garden designs.
Premium Cedar Short Post 8 in x 2.5 in x 2.5 in RCS - Premium / Classic Cedar Board 4 ft x 3.5 in RCB48 RCB48EC: The Premium Cedar Board is 4 feet long and 3.5 inches tall, the longest board available. It fits both short and tall posts and can be stained or left natural. Long boards let you build longer beds with fewer joints, reducing weak points and giving a cleaner look.
