Garden Box! DIY Masonry Box #series
Updated: Jan 6, 2020
Part 3 of our #DIY #gardenbox series!
Hopefully you've read the first post in this little blog mini series talking about the pros and cons of building a masonry box versus a wood box. If you haven't, you can find it here for a quick little review.
There are a lot of masonry materials available out there with varying degrees of difficulty, and delivering different finished looks, so take the time to really consider what would look best in your space.
#Cinderblock: painted, with stucco, or with stone veneer
#Retaining wall blocks
Retaining wall blocks are probably the easiest method, but since these are usually dry stacked, there can be movement. You may want to consider using mortar or a landscape adhesive to cut down on the chances of these moving and ending up on someone's foot. #ouch
Some of these interlock as well, which is a nice alternative and cuts down on movement.
Some people don't love the look of retaining wall blocks and they have a tendency to lose their luster and color within a few short years unless you are diligent about sealing them.
Brick looks beautiful, and it can be an inexpensive option since you can often find brick for free or for inexpensive rates on BST sites like Craigslist. Just be aware that all bricks are NOT the same size, and this variation in size can cause HUGE problems for you when building. Make sure you pick one size brick and stick to it to make your life easier!
Drawbacks to brick:
The size of the bricks means more mortar.
It means it will take more time to put it together.
More rows are necessary to obtain a good height, which translates to more opportunities for getting off level.
The thickness of the brick and the pressure of the dirt up against it makes for a weaker finished product.
It will be more prone to crumbling at a sooner rate when compared to other types of masonry.
Cinder blocks may be the cheapest alternative, and since they are large, they go up more quickly than some of the other options available.
Cinder blocks aren't very glamorous though- so they require a little dressing up.
Depending on which method you choose for prettying up your cinder blocks you can increase the price of your project significantly, so keep this in mind!
To me, one of the greatest advantages to going with a masonry garden box is the fact that you can finish it off with capstones which really gives it a more polished and professional look, and which provides you with a nice sturdy place to sit while you enjoy your garden or while you tend to your plants.
What did we choose?
We debated long and hard about which material to use and ultimately we went with cinder blocks. We got the skinny ones which make them easier to handle, more cost effective, and take up less precious space in the garden.
This box was already going in a size restricted area, so we didn't want to give up any more gardening space to the width of the blocks. We got these.
They're the full length of a cinder block, but take up half the width.
Since two sides were butting up against our fence and would not be visible we decided to spruce it up with real #StoneVeneer.
We used a #quartz material, but there are tons of options out there to fit the look you're going for. We then topped it off with capstones.
I couldn't be happier with the completed look!
It's all about that base...
An important step to consider before beginning your project is what kind of base you will have for your box.
My husband likes to err on the side of caution and was concerned with the idea of sinking and settling, so he insisted on a concrete footing along the entire perimeter of our box.
It made for a nice level surface for laying our first course of cinder blocks, even though it was additional work up front.
If you opt to skip the concrete, I suggest you still dig a trench, fill it with several inches of crushed stone and sand and tamp it down really firmly before beginning.
*Quikrete and rebar or Crushed Stone and Paver Sand
*Cinder blocks
*Mortar
*Capstones
*Paint, Stone Veneer, or Stucco Materials
*Level
*CLEAN dirt ( I recommend filling the bottom of your box with raked leaves and compost which will break down over time, thereby enriching your soil, and reducing the amount of dirt you need to purchase.
*Scrap wood and screws for building your form for perimeter footing
The Details
Step One
Start with a level area of your yard.
If it isn't level you're going to want to rake it out and tamp it down as thoroughly as you possibly can. If you are planning on building in an area that slopes severely that's okay too, if just requires a little more work. We actually ran into this issue when building one of our boxes over our wine cellar, and it CAN be done, so don't fret!
Consider how you will water your plants!
If this area gets attention from sprinklers, than you are good to go, but if it isn't- this is the time when you should consider adding a drip irrigation system to your box.
If you have a spigot close by install a splitter with shutoff valves on it. I like this one.
Then install a water timer so that you can decide when and how often you would like your crops to be watered. Doing this will save you both time and money! I like this one.
Next attach a drip irrigation hose to it and bury it to the entrance of your box, leaving a LONG length rolled up.
You can cut it after you run it up and down your rows of crops.
I've used this kind for the last several years and been super happy with the results.
Step Two
Dig a trench around your perimeter for your footing. Your trench should be wider than your cinder blocks.
We used 4" wide cinder blocks and made our footing 6" wide.
You'll want your footing to be at least 4" deep.
We made ours 6" deep.
If this was a true footing for a home you would want to be below the frost line which can vary by location.
In our area of NY this is 3' deep. For a garden box though, this isn't necessary.
Make sure that your trench is wide enough to accommodate the wood forms you'll be building as well, with still leaving a minimum of 6" in between for your concrete.
Step Three
Stone & Sand: At this point if you've decided to go with crushed stone and sand you'll want to apply that now. Fill your trench 2/3 of the way with crushed stone and tamp it down thoroughly.
Then top it off with paver sand and tamp that down as well.
You may want to allow it to settle for at least a few days if possible and then top it off with more sand.
Concrete: If you've decided to go with concrete this is where you will build your forms. It's not a house, so you don't need to get too fancy. We just used scrap pieces of wood screwed together to create ours. If you find that you have any weak spots along your forms you can support these with a spare cinder block or two on the outside of your wood.
If you're going to add rebar, this is also the time to do that. We added some into the corners and along our longest walls.
It probably wasn't necessary, but again, my hubby likes to play it safe, lol. If you do this, make sure your rebar is long enough that you can tie it into your cinder blocks.
Now mix your concrete!
We like to make ours a little more liquid so that it self levels somewhat.
You'll want to work your way around the perimeter and make sure you use a stick or piece of rebar to jiggle all the bubbles out and make sure you smooth the top out as you go.
You'll also want to allow your concrete to cure at least overnight before removing the forms and back-filling your trench.
Step Four
Alright! Now you have a nice solid base and a perimeter footing of some sort to get started!
You're going to want to start in the farthest corner and work your way around.
As you go take your time and make sure that you're maintaining level and square.
This is not as easy as it sounds! Patience is key, take my word for it!!
Your mortar joints should be between 1/2"-3/4", finger width, and you'll want to make sure you clean these up as you go as well.
Apply your mortar to the bottom of your first cinder block, line it up and you're off!
I like to go ahead and position my perpendicular corner piece (going in the opposite direction from where you're beginning) to make sure my corner is nice and square.
When you apply your second cinder block you'll want to apply the mortar to the bottom and also to the one side that will be butting up against the previous piece.
If you need to add additional mortar to any of your joints do so right away.
Mortar dries quickly so you need to move efficiently.
This is definitely a job where it's helpful to have a second set of hands.
One person should be positioning each block and applying mortar and the second person should be checking square and level and cleaning up the joints.
Now, here's the tricky part.
Cutting cinder block is NOT fun.
It's dusty work, and they easily snap or crack on you, and never where you want them too, haha.
If you are awesome at working out dimensions and math, I'm sure you can work it out to where you can avoid cuts.
Particularly if you are not restricted for space.
You have to take into account that your cinder blocks measure 4" x 16" and theoretically you should be able to stagger each course and your corners in such a way to make this work.
I would definitely take the time to sketch up your plan on paper before beginning if this is your intention though.
You obviously don't want your seams to match up from one course to the next, as this will create a weak spot in your wall.
Additionally if you have opted to use blocks with center cut outs and rebar, you will have to contend with this as well.
All things to take into account as you plot your design.
In our case we WERE super restricted for space, so we just dealt the the need to make cuts and did this as we saw fit, making sure to stagger our corners and seams.
We used a diamond masonry blade on our chop saw. It worked just fine. Make sure to wear a mask when doing this so you don't breathe in those fine particles of concrete dust!
Remember to constantly check for level and square while doing this. It's amazing how quickly you can go from 1/8" off level to an inch or more!
Step Five
You should have worked your way all the way around once before beginning your second course. This is the best way to ensure that your level is good up to this point. If it isn't, go back and fix it now!
Repeat the process with your second, third and fourth courses until you've reached your desired height.
Allow your walls to cure thoroughly before continuing or before going above 4 courses of block.
Step Six
If you're planning on putting in a path, I suggest doing it now.
Capstones jut out and can get in your way in tight corners and if you're going to finish your walls in stucco or stone veneer it looks like a more nicely finished product if your path is already in. You can do this with pavers, bricks, stepping stones, crushed gravel, or just about any other material you like.
We grabbed one of these concrete stepping stone forms and made our path from that! We already had retaining walls in that area that were gray and decided not to compete with it, so we kept the natural gray concrete color, but they also sell these awesome dyes that you can add to your mix to create whatever color path you want!
Step Seven
Now you get to make it pretty!!
Capstones should go in before you add stucco or stone veneer so that you don't have gaps.
It creates a better looking finished product.
We went with these capstones because they looked nice with the quartz veneer we picked out, but there are tons of options available out there.
You should have a slight overlap when you apply these on top of your walls.
We used mortar to attach ours, but you can also use this landscape adhesive which is meant for these types of applications.
I feel that mortar works better, but the adhesive is a lot easier to apply, and it's easy to use if you ever have a stone get loose and you need to reattach it.
You may need to make some cuts to your capstones.
We used the same diamond masonry blade on our chop saw to make our cuts that we used for our cinder blocks.
Step Eight
If you're just painting, this is the easy part and you're done- yay!!
If you're going to apply stucco and then paint, then this is the time for that! We personally didn't feel confident in our stucco abilities, particularly with the freeze/thaw cycles we get in the winter on Long Island which is why we opted not to go this route.
We used this real quartz stone veneer for ours, and I absolutely love the finished look.
These pieces went up SO easily and they were relatively inexpensive.
We did apply a few coats of sealant to our finished garden box after we were done.
What do you think of our finished box?!? Share pictures of your boxes in the comments!
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