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Friday, May 5, 2017

The Time We Built Concrete Block Planter Boxes

A garden is important to me.  I like to grow fresh vegetables and I like to work outside with my children.  So when my husband and I bought our house at the end of April I made creating a garden area a priority.  Little did I know it would take us until the first week in June to actually move in (read about this experience here: The Time It Took Us A Month To Move In).  Of course, this is South Carolina, where planting season starts in the beginning of March, so I was already MONTHS behind getting my garden ready.  I started by planting seeds with my little ones in some small pots on the front driveway.  Squash, Zucchini, Green Beans, Tomatoes, Basil, Rosemary, and Bell Peppers we planted and I stepped away thinking I had plenty of time to get the garden ready.  I was wrong!

Our first seedlings for the house garden (that had yet to be built).
Apparently, in South Carolina plants grow much faster than they did back in Virginia (which was the climate I was used to).  The hot, humid, sunny conditions in South Carolina made our seeds germinate and begin to grow within the first week and soon I had seedlings that were in desperate need of a permanent home.

We had planned on building planter boxes in the side yard from the beginning.  But we hadn't decided what exactly how we were going to do it.  So, we did what any DIYer would do: we turned to Pinterest and YouTube for inspiration and tutorials.  Here are just a few of our inspirations (which you can find on our Yard Work Board on Pinterest):


In the end, we decided against wood planters because of the dangers of wood preservatives leaching into our garden soil AND because of our highly humid and hot climate (we were afraid that the wood would mold, rot, or deteriorate too quickly).  And we determined that we wanted larger deeper planters that could also serve as additional seating (remember my previous post where I said we wanted to throw parties in our back yard??) and would provide adequate depth for most of our plants (remember the previous post when I talked about the excessive sand and roots in our yard?).  We also wanted the ability to potentially turn these planters into mini green houses with covers so that we could still grow outside in the Fall and Spring (little did we know, you can do that in the Coastal South without using greenhouse covers).  

So, after we decided on measurements and calculated the needed materials we set off to LOWES mid morning one weekday.  Of course, just like any other project we didn't fully realize the scope of what we were doing.  At the time, we drove a Nissan Armada.  Big strong car, can carry lots of stuff... well apparently it CAN'T carry 96 concrete blocks, 20 bags of gravel, 20 bags of top soil, a roll of black plastic, and a roll of landscape fabric... We ended up making three trips (yes, THREE TRIPS of loading materials into the car then driving them home and unloading them, then going back and doing it again).  See, if it were just my husband and I doing this it would have been easy.  But remember: we have kids.  They needed to eat, they needed to run, and they don't like shopping.   Needless to say, it took us the entire day to get all three loads to our house and unloaded.

My plants needed somewhere to live, and fast.  So, we did what any exhausted set of DIYers would do:  built them that night.  That's right, as soon as the kids went to bed we set up our work lamps and got started building out planter boxes.

10 Steps to Build A Concrete Planter Bed:

1.  Level the Foundation.  We had a significant amount of roots and debris that we needed to clear before being able to begin the actual building process.  We used a level and made sure that the foundation for our planter beds was as flat as possible.

2. Begin to Lay Concrete Blocks.  Some DIYers will recommend laying a foundation of sand, then gravel before laying the concrete blocks.  This is mostly for drainage and stability.  We opted NOT to do this.  Remember, we live in South Carolina and the ground is mostly sand in the first place, so drainage isn't a real issue.  We decided not to lay gravel under because we wanted minimal settling (remember also that this ground was fairly solid because of dense root compaction, had we added gravel the concrete blocks would have settled more over time as the gravel settled causing it to become uneven).

Step 2: Laying the blocks.  We staggered the levels and stacked them 3 levels high.
3.  Lay Plastic Around Interior Sides.  In between the 2nd and 3rd layer of block lay black plastic down the side of the bottom layers (using the 3rd layer to hold it in place).  This will prevent leaching of moisture through the cracks of the concrete block.  You will probably have to cut the plastic to the appropriate size, making sure to overlap the corners and along the bottom for maximum coverage.

Step 3: laying the black plastic along the interior
 4. Lay Landscaping Fabric. along the bottom interior of the planter bed.  Laying landscape fabric at the bottom allows for infiltration of water (because unless you cover these they will accumulate water from rainfall) but protects the planter from getting growth up through the bottom, which is important in our area because of the tree roots).

5. Check, Recheck, Triple Check Level.  Make sure to check the level for each concrete block that you lay and adjust the ground under the block if it's not level.  Each block is slightly different so you may find that sections need to be re-leveled.

6.  Repeat Process for Multiple Planters.  If your building multiple planters, now is the time to build the next one.  Wait to fill your planters until they are ALL done.  This will save you time while pouring gravel and top soil in the end.

7.  Pour Drainage Gravel in the bottom.  We put enough drainage gravel in the bottom of each to have roughly 6 inches depth (roughly the height of 1 layer of block).  This is a sufficient depth in our area to allow maximum drainage.  Rainfall averages vary, so make sure to do some research on your local climate to find your optimum drainage gravel depth.

8.  Fill in Top Soil.  Fill top soil until the top of the 2nd row of block (about 6 inch depth.  Why leave 6 inches of space at the top?  Top soil will settle, so you'll have to fill in more after the first rainfall.  Plants will also need protection and that 6 inches helps provide that.  If your in an area like ours, rabbits and other small creatures will want access to your little veggie treats, so that 6 inches is like a natural fence to help prevent your plants from getting eaten.

9.  Cap the Tops of the Blocks.  This is something we didn't want to do at first.  We wanted to use each of those block openings for additional plants.  So for the first growing season our planters looked like this: 
The first season, we grew squash, herbs, and strawberries inside the block openings around the planter.

Sure, this gives you optimum space for planting, but do you see the problem it causes in this picture??  Yeah, leaching.  The soil from the perimeter plants ended up seeping through the bottom of the blocks (remember that layer of black plastic we put in there?) and caused a significant amount of staining.  If this doesn't bother you, then sure, use the small areas for planting, but if you find it as unsightly as we do we suggest capping the tops.  We capped them the next summer and were much happier with their usefulness as a seating area AND they stayed cleaner looking.  *you will also see below that we added our fence by that next season, so check out our future post on this!*

See how much more clean and finished they look with caps? 
10.  Plant your Seedlings and Watch them Grow!! Yey!  You've made it through with some beautiful concrete block planter beds!!  Now it's time to fill them with our favorite plants and watch them grow!! Make sure to monitor the water so that you they neither dry out or over saturate.
My two little ones planting rows of Green Beans, Peas, and Wax Beans

We got some great growth in these planters that season! This is just 3 weeks after planting seeds.
We planted our tomatoes in pots so that we could move them to the front yard,
check out my future post about my tomatoes!
Have you made DIY Planter Boxes?  What technique and style did you choose?  Please share your thoughts and stories below.  And don't forget to come back and see our future posts on the Fence, Tomatoes, and all of our other great DIY Fixer Upper Adventures!!


  1. This looks amazing! I have to share this with my mom. I know she would love to do something like this in her backyard :) Thank you for sharing.

    1. And it's a relatively easy project!! The only hard part is getting the concrete blocks to your house lol I definitely recommend delivery unless you have an SUV or a trailer

  2. I love the way it looks with the caps on! I could probably do something like this myself.

    1. It was super easy!! And it looks soooo nice in our yard!! The hardest part was getting the supplies to the house. Definitely get it delivered unless you have a truck, SUV, or trailer!