Creating Custom Poured Concrete Raised Garden Beds

Actually, these are garden beds made of concrete blocks that have surface bonding cement on top of them, but that title was too long. Ha!.

I wanted to put some berry plants next to our septic lines and along our fence, but I wasn’t sure how to do it. poop berries or a clogged septic system, so I had to figure out how to keep the berries off the ground for 10 feet.

Concrete block beds seemed like a good choice, but I didn’t want them to look like concrete blocks. I found this QuikWall product from Quikrete that not only makes the blocks look nicer but also sticks them together to make a strong, long-lasting structure. When I began this project last year, the only tutorials I could find were for small walls, so it was all a bit of a test. It made sense, though, that if this stuff could hold up walls, it could handle a garden bed that was eight feet high. And it did!

*I used 19 concrete blocks, 19 caps, and about 1. 5 bags of surface bonding cement per bed. I found my concrete blocks from Home Depot for $1. 45 a piece.

*I ordered QuikWall from my local tile shop because I couldn’t find it at my local big box store. I think some stores carry it.

**You want to use a gravel that can be compacted like what is used in driveways. There is “minus,” or gravel dust, that gets between the rocks and helps them pack down so that you don’t sink when you walk on them. Do not use pebble gravel or any gravel that has smooth rocks. This will not compact and will create an unsteady base for your blocks.

I put together a video tutorial below that documents what I did. It shows you how the mixture looks being spread on, which is probably the most helpful part. You should still read the written tutorial because it has a lot of information I left out of the video because it would have been too long.

I sometimes use the word “cinder” in place of “concrete” when describing these concrete blocks. These words are often used to mean the same thing, and I wanted to use words that would be easy for people to understand. I also used them interchangeably, not knowing there was an important difference, until I shared this post.

Older cinder blocks are made with fly ash and contain chemicals that can be harmful to your health. Newer concrete blocks that you can get at the hardware store do not contain fly ash. They are made of water, stone, and concrete and they are safe for food. If you are using these beds to grow food, please use new concrete blocks.

Raised garden beds made from poured concrete offer the ultimate in customization for gardeners. With poured concrete you can create raised beds of any shape size, or height to perfectly suit your space and planting needs. Follow some simple steps to build your own poured concrete raised beds from scratch.

Benefits of Poured Concrete Raised Beds

Compared to other raised bed materials like wood, poured concrete offers several advantages:

  • Total custom sizes and shapes – Build beds of any dimensions with curved or angled sides if desired.

  • Very durable and permanent – Properly built poured concrete raised beds will last for decades without rotting or deteriorating.

  • Integral drainage – Drainage weep holes can be installed in the concrete sides during construction

  • Decorative potential – Concrete can be stamped, painted, stained, or tiled for decorative visual appeal.

  • Contain spreading plants – The solid concrete sides prevent aggressive plant roots or seeds from spreading.

  • Height for accessibility – Concrete beds can be made taller than wooden versions, reducing bending and strain.

  • Weed prevention – Concrete won’t harbor weed seeds like soil beds.

While poured concrete requires more initial effort and cost than other materials, the results are long-lasting raised beds that become a permanent garden fixture.

Plan and Design Your Beds

Before pouring concrete, some key planning steps will ensure success:

  • Decide on location – Choose a sunny flat spot near a water source.

  • Determine shape and dimensions – Account for reach, height preferences, and planting plans. Common sizes are 2-4 feet wide and 8-12 feet long.

  • Maximize sunlight – Orient the length along the east-west axis to ensure 6+ hours of direct sun.

  • Incorporate curves or angles – Create interest with non-rectangular beds if desired.

  • Sketch plans – Draw your design with exact shapes and dimensions to follow.

  • Pick drainage method – Weep holes, gravel layers, and fill trenches can all assist drainage.

Thoughtful planning results in raised beds tailored to your space with the access and features you need for gardening enjoyment.

Prepare the Building Site

Constructing the raised beds involves first preparing the ground:

  • Level and clear the site of weeds/debris.

  • Dig trenches 12+ inches deep where beds will be located.

  • Fill trenches with gravel, pack down firmly.

  • Layer perforated drainage pipes on top of gravel.

  • Run drainage pipes away from bed locations.

  • Construct forms – Build wooden forms to desired dimensions.

This provides a stable gravel foundation for the beds with integrated drainage.

Mix and Pour the Concrete

With proper forms in place, it’s time to pour the concrete:

  • Mix concrete to a firm, workable consistency.

  • Place concrete in forms, tamp down to eliminate air pockets.

  • Smooth and level surface with a trowel or board.

  • Insert drainage weep holes if desired.

  • Allow concrete to fully cure for several days before removing forms.

  • Paint, stain, or stamp concrete if adding decorative finishes.

Allowing adequate curing time results in solid raised beds ready for soil and plants!

Add Soil and Plants to Complete

The final steps are to fill your custom poured concrete raised beds:

  • Loosen any compacted soil and add gravel for improved drainage.

  • Fill bed with quality potting soil up to 2 inches below the rim.

  • Consider installing drip irrigation.

  • Plant selections suited for raised bed growing.

  • Include a mix of vegetables, herbs, flowers, and companions.

  • Place taller plants towards the center or north end.

With plants in place, your hand-crafted poured concrete raised beds are ready to become a bountiful focal point!

Maintaining Poured Concrete Beds

A few simple maintenance tasks will keep poured concrete raised beds looking their best:

  • Weed regularly to prevent roots from compromising the concrete.

  • Replenish mulch annually to suppress weeds and retain moisture.

  • Check weep holes and clear any debris clogging drainage.

  • Remove a few inches of soil annually and amend with compost.

  • Repaint or re-stain concrete when needed to refresh appearance.

  • Repair any cracks or deterioration promptly to prevent further damage.

With routine care, properly constructed poured concrete raised beds will serve as a permanent garden bed for 30 years or longer!

Is the Effort Worth It?

Building custom poured concrete raised beds requires more labor and skill than using pre-fab kits or materials like wood. But the benefits often justify the extra effort:

  • Unique beds that become a stunning garden focal point

  • Completely customize size, shape, and height

  • No size constraints of pre-made options

  • Permanent beds that last for decades

  • Reduced maintenance without wood rot, pests, or weeds

  • Options like curves, tiles, or colors personalize beds

For gardeners willing to tackle the project, poured concrete is the ultimate medium to build their dream raised garden beds from scratch. The work leads to an enduring growing space providing year after year of planting and harvesting enjoyment.

poured concrete raised garden beds

Step Three: Add a gravel base.

Put down at least 1 to 2 inches of gravel where the blocks will go. Use a hand tamper to pack the gravel down and level it as you go. I had to add about 3–4 inches of gravel to some of my beds that were on a slope.

Don’t worry too much about how level the gravel is just yet because you will probably have to change how much you need in the next step.

Step Four: Add concrete blocks.

Now is the time to get picky about leveling. As you add your concrete blocks, ensure that they are perfectly level. You may have to add or subtract gravel to get this just right. Also, I suggest re-compacting any gravel that has been moved around. I didn’t always do this and later regretted it (I’ll explain at the end).

This step takes the most time, but it’s very important to do it right because it affects how stable the beds are and makes the next steps much easier.

The Best Raised Garden Bed Option for you!

FAQ

Can you use concrete for raised garden beds?

Raised beds can be placed on paved surfaces, including concrete and asphalt, with some modifications to support drainage and healthy plant roots. #2: How tall should raised beds be on concrete? Ideally, a raised bed on concrete should be 32 inches tall in order to give the roots access to nutrients and room to grow.

Is concrete safe for growing vegetables?

Beck says that concrete less than one year old can leach lime, affecting soil pH and suggests that lining the planter can prevent the lime from entering the soil.

How many cinder blocks do I need for a 4×8 raised bed?

Leaving a 1/4″ gap between every third cinder block, place the blocks hole side up. 20 blocks will give an interior bed area of 4′ x 8′.

How to start raised bed gardening on concrete?

Once you have selected the plants for your garden, it is time to move on to step two: preparing the concrete. Before starting raised bed gardening on concrete, you must prepare the concrete surface. First, remove any loose debris or dirt from the surface. Next, clean the concrete with a garden hose or pressure washer.

What can you plant in a concrete raised bed?

Plant trailing greenery – Let the concrete bed frame your garden view by training vines or trailing plants along the edges. Ivy, jasmine, vinca, and English ivy all work well. Use as divider – Position a concrete raised bed in your yard as a garden divider or border.

How much does it cost to build a concrete garden bed?

If you add up costs for materials, labor, tools and decor, building your own concrete raised garden bed typically runs $100-$500 depending on size. Pre-made concrete planters can range anywhere from $250 on the low end to $1000 or more for intricate designer raised beds. Here are the costs associated with a DIY concrete block raised bed:

What is a concrete raised garden bed?

concrete raised garden bed are becoming an increasingly popular choice for home gardeners. These raised beds are made of strong, long-lasting concrete. They let you grow flowers, herbs, vegetables, and more, and they look nice in your yard as well.

Can raised beds be placed on concrete?

Raised beds can be placed on paved surfaces, including concrete and asphalt, with some modifications to support drainage and healthy plant roots. #2: How tall should raised beds be on concrete? Ideally, a raised bed on concrete should be 32 inches tall in order to give the roots access to nutrients and room to grow.

How tall should a concrete raised bed be?

Decor potential: Concrete allows for tons of customization when it comes to color, textures, finishes. This allows your new garden bed to be an attractive focal point. Height: Concrete raised beds can be built taller than wooden versions, which reduces bending and strain for gardeners. Often 12-18 inches tall.

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