Finding plans to build long, narrow planter boxes for your windowsill is easier than you think. For free, high-quality DIY plans, your best starting points are dedicated woodworking and gardening websites. Platforms like Ana White, Instructables, and DIY Network offer numerous free, step-by-step guides tailored for urban spaces. Simply search using terms like "narrow windowsill planter," "urban window box," or "balcony planter plans.
These plans typically provide a complete materials list, cutting diagrams, and assembly instructions. They are designed for various skill levels, often using common materials like cedar, pine, or even repurposed wood. When choosing a plan, ensure the final dimensions fit your specific windowsill's length and weight-bearing capacity. Building your own allows for perfect customization to match your space and style, turning a simple sill into a thriving green oasis for herbs, succulents, or flowers. Remember to include drainage holes and consider a protective liner for the longevity of both your planter and your windowsill.