A raised cinder block raised bed can be a really budget-friendly way to construct a garden if your woodworking skills aren’t quite up to par. Read on to learn about how I built mine, and how you can make your own raised beds, quickly and easily.
To build my first basic bed, I visited a local home and garden recycling/wholesale center for blocks, and paid around $0.25 each. This was great compared to the $2.00-$6.00 that they would have cost at the hardware store.
Once I was comfortable with using cinder blocks, I built upgraded concrete and lumber beds using planter wall blocks. These are as tall as three feet high! It’s so nice being able to maintain the beds and harvest veggies while standing up.
Ideas for a Cinder Block Raised Bed
I got my ideas after talking to a neighbour who’s quite the gardening master. Cinder blocks are especially ideal for creating garden beds, because they serve several purposes. You can plant pretty much whatever you like in the main bed, and then tuck herbs and smaller plants in the spaces around the bed’s periphery.
Picture a bed of Roma tomatoes, bordered by thyme, basil, and rosemary. Mint is also a great choice for these spaces, since it stays contained. Otherwise, it’ll spread and take over gardens in no time flat. Obviously, you’re not limited to edibles, as your block garden is open to whatever you can dream up.
As mentioned, you can develop your bed with a mixture of blocks and lumber to create a single or a modular framework. Alternatively, just use blocks to build a basic square or rectangular bed.
So Many Options to Explore
A cinder block raised bed is also wonderful because there are so many options available. You can really go down a rabbit hole and build your garden into any configuration you like. Unlike a standard rectangular bed, you can build it up to save on space.
You can arrange the blocks in a geometric pattern, for example. Paint or stencil designs on the blocks to really dress up the space. If you’re so inclined, you can also rig up an irrigation system using some of the hollows.
There are tons of images available online to help jump-start your creativity. Dig around, and find ideas to build the perfect design for your space. As you search, make notes of the following:
Height: Do you want your beds to be of various heights or all uniform?
Space: How much yard space do you have to work with?
Location: Where’s the best location for the plants you’d like to grow? Will you build against a fence/wall, or in an open space?
Extras: Do you want to add a hoop cover, cold frame cover, or any irrigation?
Planter wall blocks: These 7.5″x 7.5″ x5.5″ blocks look great, and provide a solid framework for a lumber/stone hybrid bed. We built our permanent beds using this method and they get tons of compliments. Ours are built up at varying heights to suit everything from potatoes to garlic.
These blocks have center holes, which are ideal for adding hoop covers for protection from animals and the elements. It’s also really simple to just slide in 2’x6′ boards to build up the walls. Our toddler loved helping to slide the boards in, no nails required! We built a set of three beds, which can be seen further below.
Concrete bricks: Unlike clay bricks, red concrete bricks will stand up to the elements. This makes them a very budget-friendly alternative to build with. At around $0.30 per brick, these 4″x2″x8″ blocks make building a cost-effective garden bed a snap. You may want to use a thick layer of mortar, as bricks slip and settle more than heavier blocks.
Concrete blocks: These heavy-duty blocks are typically used for building concrete walls. At around $1.00 each, they’re a good middle-of-the-road option. Super durable, these 8″x8″x16″ blocks will help you build a strong, secure bed.
Two large cavities in each block provide ample space for border plants. They’re especially good for varieties that need to be contained to avoid taking over the entire bed (e.g. lemon balm, fennel). I keep a few of these on hand for various types of mint plants, and tuck them in beside the gardens, rather than having pots all strewn about.
Concrete Block Benefits
Unlike lumber, cinder blocks will never rot, and the beds are only as permanent as you want them to be. They’re simple to build with, and you’ll likely note some toned arms by the time the project is complete. In addition, they don’t need mortar or adhesives if you’re building a two-foot bed or lower.
A bonus of using concrete blocks is the fact that they have holes. These are great for holding support posts for fencing, cold frames, or hoop covers. The blocks are also easily replaceable when they do eventually wear down. They also tend to hold heat better, and keep the soil warmer year round, with better drainage.
Concrete Block Cons
There aren’t many cons, but consider that the lime that can leach from actual cinder blocks (not concrete blocks) can alter your soil’s pH level over time. Of course, they’re also pretty heavy, which might make this method off-limits for some.
In drier climates, it can take more effort to keep the soil moist due to the increased drainage. Some people might even find them less than attractive at first. Really, once the beds are filled with beautiful greens, what’s not to like?
How to Build Your Bed:
For my very first bed, I built a smallish round structure out of “rocket”-shaped blocks. It was all I really needed at the time to separate plants from grass. I found that the key for a nice, sturdy bed was to make sure the ground was levelled first. Don’t skip this step, or you’ll wind up with a wobbly bed that’ll need constant adjusting.
Use marking paint, chalk, or twine/stakes to measure and mark out where you want to place your bed. Next, dig out the area with a good shovel until it’s as even as you can get it. If you’ve got nice, workable soil, you can get away with skipping the next step.
If you’ve got bedrock or an altogether uneven landscape, you’ll need to even out the surface with gravel or paver base. Build it close to a water source, and make sure it gets lots of good sunshine.
Work Slowly and Carefully
Lay out your blocks, making sure each is level to the ground, and to the next block beside it. You’ll probably want gloves for this step to help you keep a good grip. Wear close-toed or steel-toed shoes to protect your feet. Build up the first layer, then start on the second.
If you like, you can use mortar or construction adhesive to really hold it all together. This is especially important if you’re using smaller, lighter blocks like bricks. Since I knew my flower bed border (above) would be a temporary solution, I opted to skip the mortar.
Work slowly and carefully. It’s tempting to rush through this step and get on to the good stuff, but the more time you spend, the more even and uniform your bed will be, especially if you’re using an adhesive substance.
And Now, The Filling:
Once all the blocks are added, layer cardboard or newspaper thoroughly inside the perimeter to stop weeds from springing up.
Next, add your soil. Alternate soil with organic compost, fertilizer, and manure until the bed is completely filled, since it’ll settle over time.
The amount of soil you need will vary depending on the size of your cinder block raised bed. If you’re unsure, provide the garden center or supply yard with your bed’s measurements and they can help. Depending on depth and dimensions, you might only need a wheelbarrow full, or you might use up several pounds of soil.
Fill the perimeter holes with the same rich mixture. Plant flowers, veggies, or berries in the main garden section, and plant seeds or seedlings around the periphery. There are so many options at this stage.
Try planting tomato-friendly marigolds in some spaces, and savory herbs in others. Strawberries are quite happy in these hollows as well, and their blossoms would add contrast to the rest of the greenery. For a low- maintenance border, succulents or trailing perennials add a lot of visual interest.
Whatever you choose, your garden is sure to be beautiful and productive as long as it’s sturdily built and properly cared for. This makes a great project for nearly any time of year and for any type of landscape, whether you’re envisioning flower beds, veggie beds, or a clever mix of both.