DIY Raised Concrete Garden Bed

When we moved into our house years ago, I built a simple square firepit in the backyard. I think it is time for an upgrade! This DIY Raised Concrete Garden Bed has been such an improvement to my backyard!

Prep Work Process

The first thing I have to do is get our utilities marked so I know what to watch out for. Once these are marked, I am beginning to dig up sod! I am building this in the corner of my fenced-in backyard. To get the ground leveled, I strung a line and dug out roots and rocks until it was 4″ down.

Building the Base of the DIY Raised Concrete Garden Bed

For most of the area, I laid down class 2 crushed granite as a stable substrate. Where I want to build the concrete planter, I am compacting a paver base 2-3 inches thick. I got a huge delivery of all the cement blocks and bags of mortar from Home Depot. I am hiring my neighbor with professional concrete experience to help me. His mixer was very helpful to have as we worked together to lay blocks. We are measuring the corners of the L-shaped planter and then stringing a line to keep our course straight.

Each block is set in mortar and has mortar between. I struck each mortar joint and broomed them off. We measured with a laser level to ensure the wall was level across every time we set up our line for a course. After three courses, I pounded down a 4 ft rebar in the center of a block core roughly every 3 feet. Then, I core filled with concrete. This will stabilize the wall and prevent cracking from Minnesota’s extreme freeze and thaw cycle. I then laid the fourth and last course of blocks with a paver style. I did this so there is more space for soil in my planter at the top.

Finishing Work

To finish my DIY raised concrete garden bed I am coating the cement blocks in water with my sprayer. Then, I go in with my stiff bristle brush to take off any excess mortar and imperfections. I am doing this because I am doing a feather finish using Surecrete Sure Broom. This is a concrete product that I have left over from when I did my steps. This product is meant to be used when refinishing concrete. It was a little difficult to use this on a vertical surface as it is very thin, I ended up pouring cups of it on and then spreading it out with a squeegee.

When that is dried, I put pieces of plywood over the holes of the cinderblocks that are inside the planter. I am dropping the extra concrete blocks into the hollow center of the wall. In addition, I am dropping in the rocks that I dug up and pieces of trees that I have cut in the past. Once all of the fill is in, I am covering it all with dirt. I am using 10-12 inches of soil.

Now that all of the soil is in place, it is time for the fun part: plants! All of the plants are native species to Minnesota. I am excited to have a raised garden bed because it will help me control and care for them adding to this have them in a so they don’t spread all over.

Facing Some Issues

I should have stopped at this point, but it was really bothering me that the thin coat of Sure Broom was allowing me to see all of the block lines. It did not give me the smooth finish I had envisioned, so I went to the store and picked up a crack-resistant surface bonding cement. I mixed it up and applied it to the wall, it was thicker and smoothed out all of the brick lines. There was a downfall: there was fiberglass in this product, so when it dried, it looked like it had fuzzy hairs in it. This made it look worse!

I have to figure something out to make it look better! You can’t win them all, stay tuned to see the final result of this entire project and what I did to resolve the concrete issue!