Outdoor Planters from Rain Barrels and Pallets-
I wanted a durable, deep, and urban chic way to grow hops in my little concrete backyard in Philly. I found that rain barrels can be had for cheap or free. With the rain barrel cut into a trough, it is a deep 22.5 gal basin that can withstand cracking apart in the cold winter and weight of gravel and dirt. Pallets can be nabbed up for free, and since they are all the styling rage, and I'm cheap, the only real cost of this project was pressure treated wood.
The reason why I had the gravel and dirt in the barrels as I built it is because I first had built a prototype without pressure treated wood. It didn't last long. I acquired more barrels and shifted the gravel and dirt around.
Step 1: Building a Frame
Rain Barrels used here are 22" diameter x 38" height. A frame built around them must have inside dimensions of 22" x 38", outside diameter is 25" x 41" using 2" x 4" lumber. I cut four 25" pieces to be the side tops and bottoms. The tops are joined to two 38" pieces to form a square. I picked a height of 18" and used a kregg jig to make pocket holes to join the top square to the leftover bottom 25" pieces. I picked a height that would be nice to have a ledge and sit on. Depending on your plant choices and landscape, you may want taller planters.
Step 2: Cut the Rain Barrel in Half, Mount to Frame
I cut the rain barrel in half so that I used the seam as a guide. The two openings in the top became bisected. I cut the lip off the top to help get the barrel flush to the frame. Use outdoor deck screws as they are weather resistant. Drywall screws are brittle and will rust apart.
Step 3: Drill for Drainage, Add Gravel and Dirt
After mounting to your frame, add holes for drainage. I used a small spade bit and made 10 holes in two rows at the bottom of the barrel. Then add gravel, and dirt. Hops require lots of water, but also lots of drainage.
Step 4: Top Ledge
I made 45 degree angle cuts with pressure treated 1" x 4". In hindsight, I would keep the ledge as straight and 90 degree angles. The 45 degree has separated due to shifting and expansion and contraction. I may put a small 90 degree angle bracket under the ledge at the corners.
Step 5: Add Pallet Wood As Facade
Tear apart some pallets and get screwing. For my yard I only did the outside facing front. I like to be able to clean underneath with a hose. Feel free to stain, paint, or polyurethane your wood.
Step 6: Plant and Decorate (LEDs, Gnomes, and Flamingos!)
Get it green! Run some ropes up to the roof for hops, add string lights, pour some beer and wine, and enjoy your yard.