How to Build a Planter Box on a Budget: Simple DIY Guide

Building your own raised garden beds doesn’t have to cost a fortune. With some basic lumber and simple tools, you can create functional and attractive planter boxes that transform your garden space. This guide shows you how to build a sturdy wooden planter box without breaking the bank, perfect for growing vegetables, flowers, or herbs.

Key Takeaways:

• Build substantial, budget-friendly raised garden beds using standard lumber sizes.
• Follow simple cutting lists for two common sizes (medium 5’x3′ and large 8’x4′).
• Use basic tools like a miter saw and drill for assembly.
• Learn a smart layering technique to fill deep beds and save on topsoil costs.
• Create durable planter boxes ready for planting season.

Have you been dreaming of a lush vegetable patch or a vibrant flower display, only to be daunted by the price tags on ready-made garden planter boxes? You’re not alone! It’s easy to get discouraged when faced with the cost of transforming your backyard into a productive oasis. But what if you could build your own durable, large garden boxes without spending a fortune? This year, we decided to take our garden dreams into our own hands and figure out how to build a planter box on a serious budget, and we’re excited to share just how simple it can be.

Our garden journey started a few years ago, and after tackling house renovations, it was finally the garden’s turn for attention. Last year, we used some old railroad ties for makeshift beds, which worked okay, but we craved something more intentional and uniform. We leveled a new area, fenced it in, and knew that sturdy, raised planter boxes were essential for the garden we envisioned. Discovering the high cost of store-bought options quickly led us down the DIY path – proving that building a planter box yourself is often the most economical and customizable solution.

Large wooden planter box being built in a garden area

Why Build Your Own Raised Garden Boxes?

Beyond the significant cost savings compared to purchasing pre-fabricated kits or assembled beds, building your own planter boxes offers complete control over size, shape, and materials. You can tailor them perfectly to your garden layout and specific planting needs. Plus, there’s a real sense of accomplishment that comes from seeing your handmade boxes take shape, ready to nurture your plants.

Overview of a leveled garden area fenced in, ready for planter boxes

For our garden, we decided on two main sizes to accommodate different types of plants: a medium size perfect for rows of veggies and herbs, and a large size ideal for sprawling plants like pumpkins and squash. By carefully planning our cuts, we aimed for minimal material waste, keeping the project firmly within our budget goals.

Gathering Your Planter Box Supplies

The beauty of this budget build is the simplicity of the materials needed. You’ll find everything at your local lumber yard or hardware store.

• (6) 2×6 Boards (Length depends on your box size)
• (4) 4×4 Boards (For corner supports)
• Exterior Grade Paint or Stain (Optional, for protection and aesthetics)
• 3-1/2″ Exterior Wood Screws (Choose screws designed for outdoor use to prevent rust)

Planning and Cutting Your Lumber

Before you start cutting, it’s a great idea to lay out your garden space using spray paint or stakes to visualize where your planter boxes will go. This helps determine the best size and quantity of boxes for your area.

For this project, we designed two sizes aiming for zero waste from standard lumber lengths where possible.

Cut List Per Planter Box:

Diagram showing cut lists for medium and large garden planter boxes

Medium Planter Box (Approx. 5’x3′ x 18″ Tall):

• (6) 2×6 boards cut to 36 inches (Short sides)
• (6) 2×6 boards cut to 60 inches (Long sides)
• (4) 4×4 boards cut to 18 inches (Corner supports)

Note: For the medium boxes, you can often get one 60″ piece and one 36″ piece from a single 10-foot 2×6 board, minimizing waste.

Large Planter Box (Approx. 8’x4′ x 18″ Tall):

• (6) 2×8 boards (using standard 8-foot length)
• (6) 2×4 boards (using standard 4-foot length)
• (6) 4×4 boards cut to 18 inches (Corner supports)

Note: For the large boxes, standard 8ft 2x8s and 4ft 2x4s mean very few cuts are needed besides the 4×4 supports.

Use a miter saw to make precise cuts according to your chosen size(s). The 18″ height for the 4×4 supports allows them to extend slightly above the box, which is perfect if you plan to add features like decorative caps or solar lights later.

Step-by-Step Planter Box Assembly

With your lumber cut, it’s time to assemble! Try to work on a flat, level surface if possible.

1. Assemble the Long Sides: Take one of your long side boards (60″ for medium, 8′ for large) and one 18″ 4×4 support. Clamp the 4×4 to the inside face of the long board, flush with one end. The edge of the long board should meet the face of the 4×4.

   Clamping a 4×4 corner post to a long side board of the planter box

2. Check for Square: Use a framing square to ensure the corner is at a perfect 90-degree angle before fastening.

   Using a framing square to check the corner angle of the planter box assembly

3. Secure the Corner: Drill pilot holes (recommended to prevent splitting) and use 3-1/2″ exterior screws to secure the long side board to the 4×4 support. Drive the screws through the side board into the 4×4.

   Screwing a long side board into a 4×4 corner post during planter box assembly

4. Attach the Second Corner Post: Repeat step 3 at the other end of the same long board with another 4×4 support.

5. Build the Second Long Side: Follow steps 1-4 to create the second long side panel assembly. You now have two long sides with corner supports attached.

6. Add the Short Sides: Stand one of your long side assemblies up. Take a short side board (36″ for medium, 4′ for large) and position it between the two 4×4 supports, at one end. The short board should cover the edge of the long board. Clamp it in place.

   Attaching a short side board between the 4×4 posts and long side board using clamps

7. Fasten Short Sides: Screw through the short side board into the ends of the long side boards (where they meet the 4×4). Use exterior screws. Repeat for the other short side at the opposite end. This completes the first layer (or the bottom layer) of your planter box frame.

   Screwing the short side board into the corner assembly to complete the first layer of the box

8. Add Additional Layers: Stack the remaining long and short boards on top of the first layer. Align the edges and screw them into the 4×4 supports from the outside. Continue until you have three layers of boards, creating a sturdy, deep planter box.

   The completed lower half of a planter box frame with two layers

Adding the Finishing Touches

Once the box frame is assembled, you can choose to finish the wood for aesthetics and longevity.

While optional, filling screw holes with exterior wood filler and sanding smooth creates a cleaner look, especially if you plan to stain the box. For painted boxes, this step is less critical unless you desire a perfectly smooth finish.

Applying a coat of exterior paint or stain is highly recommended to protect the wood from the elements and extend the life of your planter box. We chose a durable exterior paint in black, which offers excellent weather resistance. You don’t need to paint the entire inside; just painting the top board or two is sufficient as the rest will be hidden by soil. Apply at least two coats for good coverage and protection.

Exterior of a completed wooden planter box painted black

Filling Your Raised Garden Bed Strategically

Now that your planter boxes are built and placed in their final location (leveling them as needed), it’s time to fill them. Since these boxes are deep, filling them entirely with bagged topsoil can be very expensive. A smart layering technique saves money and provides excellent drainage and organic matter as materials decompose over time.

Here’s a common and effective layering method:

1. Bottom Layer: Fill the bottom third or half of the box with coarse organic material like branches, logs, wood chips, or straw bales. This takes up space and provides excellent drainage.
2. Middle Layers: Add finer organic materials such as cardboard (remove tape and labels), newspaper, grass clippings, dead leaves, or compost. This layer breaks down faster, adding nutrients to the soil.
3. Top Layer: Fill the remaining space (the top 6-12 inches) with a good quality mix of topsoil and compost. This is where your plants’ roots will primarily grow.

Cross-section view of a large planter box being filled with layers of branches, cardboard, leaves, and topsoil

This layering approach, sometimes called Hugelkultur (when using logs heavily) or simply “lasagna gardening,” not only saves on the cost of bagged soil but also improves soil structure and fertility over time.

Adding a layer of leaves and organic matter over cardboard and branches in a large planter box

Your New Garden Boxes Await!

Building these simple, budget-friendly raised garden planter boxes is a fantastic way to create a functional and beautiful garden space. It’s empowering to know you built the foundation for your garden dreams with your own hands.

Three black wooden planter boxes placed in a garden area, ready for planting

With the boxes built, layered, and ready, the exciting part begins – planting! Our garden is now one big step closer to being the vibrant, productive space we’ve always wanted.

Two black wooden planter boxes in a garden, one partially filled, showing the scale

Even with the boxes ready, there’s always more to do in a garden! Next on our list is adding vertical structures like trellises for climbing plants.

A planted large wooden planter box with small green plants growing

Building your own planter box is a rewarding project that makes gardening more accessible and affordable.

A large black DIY wooden planter box filled with soil, ready for planting

We hope this guide inspires you to build your own garden boxes!

Conclusion

Building your own raised garden planter boxes is a practical and cost-effective way to create the garden you’ve always wanted. By following these simple steps, selecting budget-friendly materials, and utilizing smart filling techniques, you can construct durable and attractive boxes ready for planting. It’s a rewarding project that lays the foundation for a thriving garden.

What do you think of this budget planter box build? Are you planning to build your own this season? Let us know in the comments below! If you found this guide helpful, please share it with your fellow garden enthusiasts. And be sure to explore other DIY projects on Thelittle.garden to enhance your outdoor space!