A few years ago, when I was researching raised gardens, I stumbled upon the “keyhole” method of raised beds. This traditional gardening approach involves a circular mound with a central composting area that naturally enriches the soil. That got me thinking—could I apply this idea to a raised planter? The answer: Absolutely!
Living in the city, we constantly battle squirrels and rabbits that ravage backyard plantings. However, compost seems to deter them. Combined with companion planting, like mint, we’ve seen our plants flourish while keeping pests at bay. Let’s dive into how you can build your own elevated keyhole garden planter.
Why This Plan Works
- Built-in Composting: The integrated compost bin adds nutrients directly to the soil, eliminating the need for constant fertilizing.
- Pest Resistance: Compost deters small critters, while mint naturally repels squirrels.
- Space-Saving Design: The raised bed structure fits well in urban settings and protects plants from ground pests.
- Durability: Made with pressure-treated wood and cedar, this planter is built to last.
- Efficient Drainage & Soil Aeration: Proper spacing and bottom supports ensure healthy plant growth.
What You Will Need
Materials & Supplies
- (8) 2x4x96 Pressure-Treated Boards
- (14) 6′ Cedar Fence Pickets
- (1) 4x4x8 Pressure-Treated Post
- (2) 1x6x6 Pressure-Treated Boards
- (1) 7/8″ Dowel Rod
- (4) 24″ x 2″ Pieces of Steel Angle Iron
- (1) Roll of 3ft x 50ft Weed Block Landscape Fabric
- (12) 2″ Zinc-Plated Lag Screws
- 2-1/2″ Kreg Blue Kote Exterior Screws
- 1-1/2″ Decking Screws
- 7/8″ Forstner Bit or Spade Bit
Tools Used
- Kreg Pocket Hole Jig
- Circular Saw with Diablo Steel Demo Blade
- Drill/Driver
- Miter Saw
- Clamps
How to Make
Step 1: Cut Lateral Frame Supports
Trim four of the straightest 2×4s to 96″ to serve as the lateral frame supports.
Step 2: Cut Cross Braces
Cut 16 pieces of 2×4s to 19.50″ each. Pre-drill a pair of 1-1/2″ pocket holes on both ends using your Kreg Jig. On two of these cross braces, add inward-facing pocket holes to secure the center post.
Step 3: Cut Vertical Spacers
Cut eight 2×4s to 7″ for vertical spacers, pre-drilling pocket holes into each end.
Step 4: Assemble the Frame
Using pre-drilled pocket holes, assemble two rectangular frames with the lateral supports and cross braces, securing them with 2-1/2″ Blue Kote Screws. Ensure the pocket holes face outward for easy assembly.
Step 5: Assemble Inner Frame
Attach 12 pre-drilled 19.50″ cross braces to the inner frame using 2-1/2″ screws. Maintain proper spacing: outside boxes at 15″, middle boxes at 15.75″, bottom frame spacing at 3.50″, and top frame spacing at 7-1/2″.
Step 6: Connect Frames
Flip the bottom frame so the cross braces are flush with the ground. Attach the top frame to the bottom frame using 7″ vertical spacers with outward-facing pocket holes.
Step 7: Add Legs
Sand and spray-paint the steel angle iron to prevent rust. Drill pilot holes and secure each leg to the frame using 2″ lag screws.
Step 8: Attach Cedar Siding
Cut 41 pieces of cedar fence planks to 14.25″ each. Pre-drill holes to prevent splitting, then attach them to the frame with 1-1/2″ decking screws.
Step 9: Install the Center Post
Cut a pressure-treated 4×4 to 60″. Center and secure it to the cross braces using pre-drilled pocket holes and 2-1/2″ screws.
Step 10: Add Post Spacers
Use scrap 4×4 to cut two 2″ spacers. Attach them between the top cross braces and the center post using a level for alignment. Secure with screws.
Step 11: Add Bottom Supports
Cut four cedar fence pickets to 44″ and attach them to the bottom cross braces using 1-1/2″ screws for liner support.
Step 12: Add the Liner
Cut and double-layer the garden liner, securing it with screws, staples, or roofing nails to cover the planter’s bottom.
Step 13: Add Bin Dividers
Cut 12 cedar fence picket pieces to 12″ and attach them to the dividers using 1-1/2″ screws. Cardboard can be used to create a temporary compost bin partition.
Step 14: Attach Hanging Basket Support
Cut two 1×6 pressure-treated boards to 70″. Drill 7/8″ holes for the dowel rod. Attach the supports to 5-1/2″ 4×4 blocks and secure them using decking screws and lag screws.
Step 15: Install the Final Hanging Basket Support
Attach the remaining support piece using lag screws. Insert the dowel rod through the holes and trim any excess.
Step 16: Set Up the Compost Bins
Use cardboard to divide the bins, then layer gravel, sticks, leaves, and compost. Regularly stir to maintain a nutrient-rich environment.
Note: Ensure proper composting by following guidelines on what materials can and cannot be added.
Other Details Display
- Planter Depth: 14″—suitable for lettuce, kale, carrots, squash, peppers, and zucchini.
- Pest Prevention: Mint plants deter squirrels; mosquito plants in hanging baskets repel insects.
- Hanging Basket Options: Tomatoes or strawberries can thrive in the overhead space.
- Compost Materials: Include fruit peels, vegetable scraps, coffee grounds, and yard waste while avoiding dairy and meat.
Summary
This elevated keyhole garden planter combines efficient composting, pest prevention, and urban gardening convenience. By incorporating raised bed gardening principles with a self-sustaining compost system, it ensures healthier plants and a productive harvest.
With a depth of 14 inches, it supports a variety of vegetables, while hanging baskets maximize space for additional crops. Try this method for a hassle-free and eco-friendly backyard garden!
This plan is a contribution by [LazyGuyDIY]. Project Via Instructables – Get the PDF Instructions here.