This planter would work great for succulents, grasses, flowers, or strawberries. I chose to use succulents of the Sedum variety but there are a lot of different options.
To have success planting in cinder blocks you will want to use alkaline loving plants. Your also want to plant in a nice flat area. A concrete driveway or deck works well.
20 half-cinder blocks
alkaline loving plants
Find a nice flat spot to layout your cinder blocks. The half cinder blocks work great for this type of project.
If you plan on stacking higher than 3 high, you will want to run some rebar so that it doesn't topple over if someone bumps it. Even with a shorter version like mine, I would recommend using a little liquid nails to attach the 2nd and 3rd row of blocks.
Once you have your layout set up, put gravel in the bottom of all the planters. Make sure to leave room for 6 inches of soil.
Fill the blocks the rest of the way with soil.
Then put in your favorite alkaline loving plants.
I like to refer to this as our Qbert planter, since it reminds of the old video games (see below).