Adding a liner to your wooden urban planter box is a crucial step for longevity and plant health. It protects the wood from constant moisture and soil contact, preventing rot and extending the planter's life. The key is to ensure excellent drainage while containing the soil.
For most situations, using a heavy-duty plastic liner (like HDPE or pond liner) with pre-drilled drainage holes is highly effective. Poke several holes in the plastic bottom aligned with holes in the wooden box. This creates a moisture barrier while allowing excess water to escape. Avoid lining only the sides, as trapped water at the bottom can cause rot.
A popular alternative is permeable landscape fabric. It allows water and air to pass through while holding soil in, offering a good balance between protection and drainage. For an eco-friendly option, consider a coco coir liner, which is natural and biodegradable but may need more frequent replacement.
Never use non-porous materials like solid plastic without drainage holes, as this will waterlog the soil and kill plant roots. Similarly, avoid materials that break down quickly, like garbage bags.
Regardless of your liner choice, always add a layer of drainage material (e.g., pebbles or broken pottery) at the bottom of the liner before adding soil. This simple step prevents the drainage holes from clogging. A proper liner safeguards your investment, ensuring your wooden planters remain beautiful and functional for seasons to come.