Choosing the right liner for your wooden urban planter box is crucial for plant health and the longevity of the box itself. While not always mandatory, a liner serves two main purposes: protecting the wood from constant moisture and soil contact, and helping to contain the soil. Here are the best options.
A heavy-duty plastic liner is a popular and effective choice. Use a polyethylene sheet or a pond liner. Ensure you puncture several holes in the bottom of the plastic liner to align with drainage holes in the wooden box. This prevents wood rot while allowing excess water to escape, preventing root rot. Always use a food-safe plastic if growing edibles.
For a more permeable option, use a layer of landscape fabric. It allows water and air to pass through while holding soil in place. It protects the wood from abrasion but offers less moisture protection than plastic. It's ideal for improving drainage and is often used in conjunction with a plastic liner that has been holed for drainage.
In some cases, you can use no liner at all. This is suitable for rot-resistant woods like cedar or redwood. To protect the wood, apply a non-toxic sealant on the interior. Use a high-quality potting mix and ensure excellent drainage with a layer of gravel or pebbles at the bottom below the soil.
Regardless of your choice, never let soil sit in soggy conditions. Always drill adequate drainage holes in the bottom of your wooden planter before adding any liner or soil. A proper liner strategy will keep your planter box beautiful and your urban garden thriving for seasons to come.