How to Build a Raised Bed with Retaining Wall Bricks

Freestanding garden beds built above ground are known as raised beds. “Raised” indicates that the bed’s soil level is higher than the soil around it. The term “bed” suggests a space that is manageable without really entering the planting area. For structural stability and erosion control, raised beds are frequently encased in box-like frames.

Brick, rot-resistant lumber, landscaping timbers, or concrete blocks are some of the materials that can be used to build raised bed frames. For gardeners who prefer not to bend over while working, beds can also be raised.

🧱 Why Use Retaining Wall Blocks for Raised Beds

Better drainage: Blocks let water drain easily and allow roots to aerate the soil
Warmer and easier access: Beds retain heat longer and reduce the need to bend, which is ideal for gardeners with mobility concerns
Low maintenance and attractive: Blocks come in many shapes/colors and don’t leak harmful chemicals like old railway sleepers might.

🚧 Build Plans: Common Sizes

Raised bed sizes you wanted to build:

2′ × 8′ × 1′
4′ × 4′ × 6″
4′ × 6′ × 1′
4′ × 8′ × 1′
2′ × 6′ × 1′

🛠 How to Build a Bed with Blocks & Boards

Based on reliable DIY designs like the “puzzle” method:

Materials:

Concrete planter wall blocks (e.g. Oldcastle 7.5″ × 7.5″ × 5.5″)
Pressure-treated or kiln-dried wood boards (e.g. 2×6 or 2×10)
½″ rebar (for corner stability)
Level, hammer, saw, and drill

Steps:

Measure and mark the bed layout.
Place blocks at corners (and optionally midpoints for longer beds).
Cut boards to fit, then slide them into slots on the blocks.
Insert rebar vertically through block holes to secure corners before filling with soil.
Keep bed level and square, adjust before adding soil.
Fill with enriched soil, compost, and plants.

⚙ Comparing Railway Sleepers vs. Blocks

Railway Sleepers:

✅ Heavy, strong
❌ Release tar when hot, rot over time, and are hard to level or move

Retaining Wall Blocks:

✅ Lightweight, clean, easy to install and level
✅ Drain well, modular, long-lasting
⚠ May need rebar or adhesive for taller beds

If WoodBlocX had been available earlier, it could be a smart alternative—modular wood system with dowel-fit assembly. However, reviews note it can be pricey, requires careful leveling, and can be hard work to hammer in dowels.

💬 What Gardeners Say

“Looks like a very expensive way of building very basic wooden structures… if it’s going to be built and left in place then it’s not worth it.”
— Reddit user on WoodBlocX durability and cost

“Super easy raised bed” method using four concrete blocks and boards costs under $50 and needs just basic tools .

✅ Pros and Cons Table

Feature	Railway Sleepers	Retaining Wall Blocks / Wood-Board System
Weight	Extremely heavy	Light to moderate
Installation	Very difficult	Fast “puzzle” stacking or modular building
Drainage	Poor, may trap moisture	Excellent natural drainage
Rot / Chemicals	Tar leaching & rot	Clean, safe with proper material
Longevity	Susceptible to deterioration	Blocks and wood last 10+ years
Cost	Variable, often cheap	Low cost for blocks; WoodBlocX higher priced

🔧 What You Need for Your Sizes

For a 4′ × 8′ × 1′ bed:

~4–6 corner/mid blocks
2×6 pressure-treated planks cut to length
Rebar pins at corners
Soil and compost

For shorter beds, just use corner blocks and straight boards.

How to Build a Raised Bed with Retaining Wall Bricks

Breakdown of The Steps to Build a Raised Bed with Retaining Wall Bricks

Step	Description
1	Excavation Dig a level trench approximately as deep as the height of one of the bricks. Make it level with a square shovel. If needed, tamp the bottom of your trench for stability. Particularly if there’s sod, it is harder to prepare the ground.
2	Lay the First Course Use commercial grade landscape fabric in the trench, with excess towards the interior. Lay the first course on the fabric to hold it in place. Line the interior of the bricks with fabric to prevent dirt from leaking out. Do minor grade adjustments to keep it level using a trowel.
3	Lay the Remaining Courses Use landscape block adhesive between the courses to add stability. Squirt adhesive and lay blocks on top of it. Level the second row on top of the first, using a hammer and chisel for any size adjustments. Scoring the brick for cuts should be done around the brick edges.
4	Finishing it Up Backfill the bed after the final course is laid. Plant and fold remaining fabric inward, securing it in place. Top with mulch for neatness.
Materials	Square Shovel Commercial Grade Landscape Fabric Landscape Fabric Pins Retaining Wall Bricks Landscape Block Adhesive Dirt for backfilling Masonry Chisel 3-Pound Sledgehammer
Tips	For a long, curvy wall, a design can span 500 feet along a fence. Experiment with multiple tiers or add smaller beds within a larger layout. Retaining wall bricks are preferred due to their design for stability. The project can be completed within a few hours for small beds or a weekend for larger beds.

What Is the Difference Between a Raised Bed and A Retaining Wall?

Retaining walls must be sturdy enough to support both soil and water. They are typically constructed of reinforced concrete, concrete blocks, or wood. Drainage is often necessary to alleviate the accumulation of water behind the wall. Raised beds don’t have to be as hefty or robust as retaining walls. Both kinds serve to harmonize your garden style by adding structure or screening.

I was the one who constructed all of the raised beds when I originally started my garden consulting business, which was called Rooted Garden by me. As someone who is not very skilled in carpentry, I devised a straightforward method for constructing a raised bed made of wood by utilising only a drill and a bolt tightener. My decision to have the boards cut at the hardware shop was made so that I would not have to use a saw.

Cedar is a very long-lasting timber that will continue to function well for many years to come, which is one of the reasons why I enjoy working with it. Another option is to make use of pine, cypress, redwood, hemlock, or any other species of wood that is easily available in your region and does not deteriorate in a short amount of time. Regardless of the type of wood you are working with, you should steer clear of boards that have been treated with chemicals that could potentially seep into the soil (and consequently into the food that you are going to consume). You should choose a stain that is of good quality, favourable to the environment, and resistant to the elements if you do decide to stain the exterior.

Additionally, I suggest purchasing boards that are as thick as you are able to afford, preferably at least two inches in thickness. If you allow yourself to resist the urge to get anything that is only one inch or so thick, you will be able to get more use out of your raised beds and enjoy them for a longer period of time. The majority of the raised bed kits that are currently available for purchase on the internet are built of wood that is just not strong enough to last for an extended period of time. This is the reason why I offer a buyer beware warning.

📌 Final Thoughts

Retaining wall blocks offer a clean, durable, and DIY-friendly approach to raised beds and low retaining walls. They’re far easier than railway sleepers and safer than some modular systems without proper alignment. If you’re gardening in small spaces or with poor soil, this method gives you flexibility, good drainage, and curb appeal.

In this piece, you learned what raised beds are, the step-by-step process to build a raised bed with retaining wall bricks, the materials and tips needed for construction, and the difference between a raised bed and a retaining wall. For more informative guides, stay connected to Buildersviller.