How To Make A Concrete Block Planter

After ripping out some overgrown bushes next to the house a few years ago, I found myself staring at a blank, ugly corner. While scouring the internet for inspiration, I fell in love with the idea of building a large concrete block planter, and knew I had found the perfect solution for my ugly corner!

Building your own DIY concrete block planter not only looks fantastic, but you can get super creative with it, and come up with your own unique design. It’s also versatile, so you can put it anywhere – and make it as small or large as you need to fill your space.

It’s also wonderful way to try your hand at growing vertically, and is excellent for adding height to a boring empty corner like mine.

Another thing I love about this project is that it’s a wonderful option for anyone who’s on a budget. Concrete landscape blocks (also called cement blocks or cinder blocks) are inexpensive to buy and easy to find at any home improvement store.

How Much Does It Cost To Build A Concrete Block Planter?

The cement blocks were only $1.00 each; which came to $16 total for my block planter design. I needed more dirt than I expected to fill the large planter, and the dirt ended up costing almost as much as the concrete cinder blocks (see my note about how to save a few extra bucks on dirt below).

But I still built the entire concrete planter for under $30, an amazing price for this large of a planter!

I saved money by using plants that I already had in my garden, so you’ll also need to factor in the price of plants if you’re working on your project budget. Otherwise, just do what I did and take divisions of plants from your garden to fill your cement block planter.

Inexpensive concrete blocks for planters

Building A Cinder Block Planter Is Heavy Work

Before getting started making your own concrete block planter, keep in mind the blocks are very heavy. I must have moved each cinder block at least ten times in the process of building my planter, and my back was sore the next day!

I wanted to be sure to mention this to you so you know what you’re getting yourself into. I didn’t think about this when I decided to make mine.

Also, if you need a lot of blocks, you’ll probably need a truck or trailer to transport them since they are so heavy (and be sure to bring work gloves to the store with you to save your hands when loading them up).

I was able to get mine home in my car with a few different trips to the store (which is less than a mile from my house so it was easy for me).

How To Make A Concrete Block Planter

Ok, now that you know what you’re getting yourself into here (and you’re still reading, so that’s a good sign that you’re ready to build your own!), let’s get started! Here are the step-by-step instructions for building a concrete block planter…

Supplies Needed:

• Concrete blocks
• Container potting soil (or you can make your own container soil with my recipe)
• Paver base
• Level
• Tamper tool
• Work gloves

Step 1: Figure out your cinder block planter design – If you have an eye for design or any artistic ability, then you can draw your planter design on paper before you even lift your first block.

Even if you’re not artistically inclined, it’s still a good idea to sketch something out on paper and take some measurements of the area so you have an idea of how many cinder blocks you’ll need to buy.

Step 2: Lay out your planter design – Once I got the everything home, the first thing I did was set up the blocks to create a design I liked. I was hoping to come up with a really cool design, and I wanted my cinder block corner planter curved so that made it more difficult.

I recommend taking the time to lay out your blocks in the design pattern before you build your planter. It’s heavy work, but it’s worth it to make sure you like it before you build it.

At this point, you’re just stacking the blocks to get your basic design laid out. Don’t fill any of the blocks with dirt yet, we’ll do that in a later step once the design is final.

Building a block planter

A quick note about different types of cinder blocks… Once I started putting the design together, I noticed the concrete blocks I bought weren’t all the same. Some have a flat end (bottom block in picture below) and some have ridges on both ends (top block in picture).

Two different types of cinder blocks

This didn’t affect the way the blocks went together, but I had to pay attention when I built my planter so the flat ends of the blocks faced the front of the planter.

If I build another cinder block planter, I will pay attention to the blocks when I buy them to make sure they are all the same so I don’t have to worry about which blocks go where.

Step 3: Take a picture of your design layout – I played around with different block placements until I figured out the basic idea of what I wanted my decorative concrete block planter to look like. Once you have your blocks laid out, be sure to take a picture of your final design layout.

I took a picture purely for the purpose of writing this blog post; and boy was I glad I did because I referred to it often as I built the planter. Here’s my initial design layout…

Cinder block corner planter design layout

Step 4: Lay the first row of blocks – Once the design was done, I disassembled the blocks and started building the planter.

The first row of block takes the longest to lay because the cinder block planter bottom must be completely level – so be certain to use a level as you lay the block. This is super important, so don’t rush or skip this step!

If your first row of blocks isn’t completely level, then your planter will be lopsided – and not only will that look bad, it could end up being very dangerous! You don’t want your planter falling on someone!

So take your time and make sure the bottom row of blocks is completely level. I recommend using a tamper tool to flatten the ground, which makes quick work of leveling the block (actually, I don’t know how you would even do it without a tamper)!  Once the ground is level, tamp down some paver base over the top of it to create a solid foundation for the bottom row of blocks.

Once you get the first row level, the other rows will go faster since they can simply be stacked on top of each other.

Step 5: Fill the planter blocks with dirt – Once the bottom row is in place, fill the planter blocks with dirt. I recommend waiting to fill the blocks with dirt until you’re done with the whole bottom row.

Cement blocks filled with dirt are a pain to move and re-level! Trust me, I learned that the hard way.

Cinder block planter bottom must be level

Another lesson I learned the hard way (and realized after I finished my planter) was that most of the blocks on the bottom won’t have plants growing in them. Of course, I bought high quality potting soil for filling the planter.

So, if there are blocks in your planter that won’t have any plants growing in them, save yourself a few extra dollars by filling those with cheap fill dirt rather than high-quality potting soil.

Related Post: Choosing The Best Potting Soil Mix For Container Gardening

Step 6: Add extra support under the corners – After adding the second level of block to my corner planter, I discovered that my curved design created gaps that made filling some of the planter holes impossible because the dirt would just fall out the bottom. Oops!

If your concrete block planter is square, you won’t have to worry about this step. But if you copy my design and build a curved corner planter, then you’ll need to figure something out for this step too.

Wire support over planter block corners to the hold dirt in

My solution was to take some wire garden fencing (chicken wire would work too) and lay it across the gap under the block for support. Then I laid landscape fabric over the wire fencing, and placed the block on top. Whew, that did the trick!

Step 7: Add plants to your concrete block planter – When my planter was done, I filled it with zone 4 hardy succulents. Once they fill the planter and cascade over the sides, it’ll look even more amazing.

Using Concrete Blocks As Planters

One thing to note about using concrete blocks for planters like this is that the cement can cause the soil to dry out very quickly.

The corner where I built my cinder block planter is one of the driest and hottest corners of our yard. So that’s why I filled my planter with hardy drought-resistant cactus and succulent plants.

You could paint the cinder blocks on your planter to help hold the moisture in (and add a nice decorative touch), or you could install an inexpensive drip irrigation system to your planter to help keep it consistently watered.

Whatever you decide to do, just make sure that you fill your planter with the right plants that will thrive in the spot where you build your planter.

Decorative concrete block planter complete

I am thrilled with the way my cinder block planter turned out, it’s perfect in the corner of my succulent zen garden, and does a great job of hiding the ugly corner!

I get tons of compliments on it, and it will last for many years to come. Plus, since the plants are hardy perennials, I won’t have to replant it every year!

Just remember, building a block planter isn’t difficult… but it does require heavy work. So make sure you are up for the manual labor, or recruit some muscles to help you (ehem, hubby?).

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More DIY Garden Projects

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• How To Make A Raised Garden Bed Using Concrete Blocks
• How To Paint Terracotta Pots Step-By-Step

Share you tips for building a DIY cinder block planter in the comments section below.