If you're handy with tools and want to add greenery to your urban space, building your own planter boxes is a rewarding project. Start by gathering materials: untreated cedar or redwood lumber (resistant to rot), exterior-grade screws, a drill, a saw, a tape measure, and a staple gun. You'll also need landscape fabric and a waterproof sealant.
First, decide on your dimensions. A good starter size is 24 inches long, 12 inches wide, and 12 inches deep. Cut your lumber accordingly: two pieces for the long sides, two for the ends, and one for the bottom. Pre-drill holes to prevent the wood from splitting. Assemble the box by screwing the side boards to the end boards, forming a rectangle. Then, attach the bottom board from underneath.
Line the interior with landscape fabric, stapling it securely in place. This allows drainage while containing the soil. Apply a coat of non-toxic, waterproof sealant to the exterior to prolong the box's life, especially if it will be placed on a balcony or patio. Let it dry completely.
Finally, add drainage holes in the bottom if needed, fill with a high-quality potting mix, and plant your chosen herbs, flowers, or vegetables. These custom boxes maximize your limited space and provide the satisfaction of a self-built, functional garden feature.