A hexagonal herb planter brings a unique geometric charm to any garden while offering practical separated compartments for growing several herbs side by side. This design, demonstrated by general contractor Tom Silva on Ask This Old House, uses a clever double-hexagon structure that creates distinct growing zones within a single attractive frame. Whether you have some workshop experience or are just getting started with woodworking, this project rewards careful measurements and patience with a stunning result. Before diving into the cuts, take a moment to review essential outdoor building practices in our guide to building a cedar window planter box, which covers sizing and assembly fundamentals that apply to this project too.
Choosing the Right Materials and Tools
Selecting quality materials is the first step to a durable planter that will withstand outdoor conditions for years. Cedar is the preferred choice for this project because of its natural resistance to rot, decay, and insect damage. It also ages gracefully to a soft silver-gray patina. If cedar is not available in your area or exceeds your budget, pressure-treated lumber works well as an alternative. Just allow it to dry thoroughly before assembly to minimize future shrinkage. You can explore more ideas on selecting the right containers and planters for your outdoor space in our article on designing a stunning container garden.
According to the project published in This Old House Magazine (Spring 2024), the streamlined materials list requires only two cedar boards measuring 2 by 8 by 10 feet, along with thirty-six 3-and-a-half-inch exterior-grade screws. This keeps both costs and waste to a minimum. Optionally, pick up exterior wood glue for added joint strength and a wood sealer or exterior paint for additional weather protection.
Essential Tools Checklist
- Miter saw with bevel capability (30-degree setting required)
- Tape measure and pencil for marking
- Drill with a countersink bit for pilot holes
- Clamps or a helper to hold pieces during assembly
- Sandpaper in various grits for smoothing cut edges
- Safety glasses and hearing protection
- Work gloves for handling lumber
If you do not own a miter saw with bevel adjustment, consider renting one from a local hardware store for the day. The saw only needs to cut at a single 30-degree bevel angle throughout the entire project, so the rental cost is modest.
Cutting the Hexagonal Frame Pieces
The frame is the backbone of your planter, and accurate cuts are essential for a tight fit. Start by setting your miter saw’s bevel angle to exactly 30 degrees. This specific angle, when repeated six times, creates a perfect hexagon. Do not let the geometry intimidate you. Once the saw is set, every cut follows the same process. For an overview of similar planter construction techniques, check out this resource on DIY planter box construction.
Follow these steps for each of the six frame pieces:
- Make a bevel cut on one end of your first cedar board.
- Rotate the board so the opposite edge rests against the saw fence.
- Measure 20-and-1-eighth inches from the outer tip of the first cut.
- Make your second bevel cut at that mark.
- Repeat this sequence until you have six identical pieces.
The 20-and-1-eighth-inch measurement represents half the desired diameter of the finished planter. If you want a larger or smaller bed, adjust this number accordingly. The 30-degree bevel angle stays the same regardless of the planter size. For consistency across all pieces, attach a stop block to your saw’s auxiliary fence. This ensures every board is cut to precisely the same length, which is critical for a symmetrical hexagon.
Dry-Fitting and Assembling the Outer Frame
Before driving any screws, dry-fit the six frame pieces on your workbench. Arrange them so the mitered ends overlap to form the hexagon shape. At each corner, make two pencil marks on the outside faces of the boards. These marks should sit 7-eighths of an inch in from the end and 1-and-three-quarters inches from both the top and bottom edges. They will guide you when drilling pilot holes later. If you enjoy repurposing materials for outdoor projects, take a look at this guide for building a custom outdoor grilling station from repurposed planters.
Verify that all six pieces fit snugly together and that the hexagon is symmetrical. Adjust any gaps before moving to assembly. When you are satisfied with the fit, hold each corner tightly together to prevent shifting. Use your countersink bit to drill pilot holes at each of the pencil marks. Angle the bit slightly so it enters at the center of the rear board. This creates a stronger mechanical connection between the pieces.
Secure each corner with the 3-and-a-half-inch stainless steel screws. Stainless steel is recommended over standard coated screws because it resists rust and corrosion in outdoor conditions. Drive the screws carefully and avoid over-tightening, which can split the cedar. A good practice is to stop turning once the screw head is flush with the wood surface.
Cutting and Installing the Internal Dividers
The internal dividers give this planter its distinctive compartmentalized design. Keep your miter saw’s bevel angle at 30 degrees. Cut six divider pieces, each measuring 18-and-3-eighths inches long. As with the frame pieces, start with a bevel cut on one end, rotate the board, and make the second cut. Each divider’s long face should match the length of a frame piece’s short face, ensuring a perfect fit within the hexagonal frame. Achieving tight joinery requires the same precision as other detailed fabrication projects, such as this DIY soapstone countertops fabrication guide.
| Component | Quantity | Length | Bevel Angle |
|---|---|---|---|
| Outer frame pieces | 6 | 20 1/8 inches | 30 degrees |
| Internal divider pieces | 6 | 18 3/8 inches | 30 degrees |
| Stainless steel screws | 36 | 3 1/2 inches | N/A |
| Cedar boards | 2 | 10 feet each | N/A |
Place the dividers inside the assembled frame so that one end meets the frame wall and the other butts against an adjacent divider. This arrangement creates a smaller inner hexagon with six triangular compartments between each divider and the outer frame. These triangular pockets are perfect for different herb varieties. They also keep plants separated so aggressive spreaders do not overtake more delicate neighbors.
Fasten the dividers to one another and to the frame using the same 3-and-a-half-inch exterior screws. The inner connections require some creative drilling because the compartments are tight. A right-angle drill and driver attachment is extremely useful here. A standard-size drill often cannot fit inside the assembled compartments, so having the right tool makes this step much smoother.
Finishing and Positioning Tips
Once all dividers are securely fastened, your hexagon herb planter is structurally complete. However, a few finishing touches will extend its lifespan and improve its appearance. Sand all cut edges with medium then fine-grit sandpaper to remove splinters and soften sharp corners. This is especially important for a planter that will be handled regularly during planting and harvesting. Managing debris and material waste during construction is also important. Our article on temporary trash can solutions for construction sites offers practical cleanup strategies that work for any workshop or job site.
- Apply an exterior wood sealer or outdoor paint to protect the cedar from moisture and UV damage. Reapply annually for best results.
- Drill several drainage holes in the bottom of each compartment so water does not pool around herb roots.
- Line the inside bottom of each compartment with landscape fabric to prevent soil from washing out through the drainage holes.
- Place the planter in a location that receives at least six hours of direct sunlight daily for most culinary herbs.
- Elevate the planter on paver stones or pressure-treated feet to promote airflow underneath and prevent ground contact rot.
Cedar left unfinished will naturally weather to a silver-gray color over time. If you prefer the original warm tone, apply a UV-resistant clear sealer before placing the planter outdoors. Either way, the natural rot resistance of cedar gives you years of reliable service with minimal maintenance.
Planting and Maintaining Your Hexagon Herb Garden
With the planter complete, it is time to fill the compartments and choose your herbs. The six triangular sections are ideal for a curated herb collection. Each compartment holds a different variety, making harvesting straightforward and organized. Place taller herbs such as rosemary or dill in compartments that will not shade shorter plants like thyme or oregano.
Suggested herb combinations for the six compartments include basil, chives, cilantro, dill, oregano, and parsley. This selection covers the most common culinary herbs and provides a good mix of sun and watering needs. Water the planter evenly, focusing on the soil rather than the foliage to reduce the risk of fungal diseases. A weekly deep watering is usually sufficient unless you experience a heat wave.
With the right structure and finishing details in place, a hexagonal herb planter becomes both a practical gardening tool and a centerpiece for your outdoor space. The same craftsmanship that goes into this project applies to other useful workshop builds. For example, this DIY rolling paint caddy platform follows similar principles of precise cutting and sturdy assembly for a mobile workshop helper.
Building a hexagon herb planter is a satisfying weekend project that combines basic woodworking skills with creative garden design. The double-hexagon structure is visually striking and highly functional, giving you six defined growing spaces in a single footprint. With quality materials, accurate cuts, and attention to the finishing details, your planter will serve as a productive herb garden for many seasons. Gather your cedar boards, set that miter saw to 30 degrees, and enjoy building something that looks as good as the food it will help you grow.