Why Your Wall Is at Risk
Vertical gardens, by their very nature, involve soil, water, and plants in close contact with a wall. Every time you water your plants, excess moisture can seep out. Even with careful watering, constant dampness in the soil creates a humid microclimate
right against your wall's surface. This is a perfect recipe for problems. Without a protective barrier, this moisture can lead to peeling paint, unsightly water stains, and the growth of mould and mildew, which can affect indoor air quality. In more serious cases, persistent dampness can compromise the structural integrity of plaster and drywall, leading to costly repairs far beyond the expense of the garden itself.
Choosing Your Waterproof Backing
Selecting the right waterproof material is the most critical step. Your choice depends on your budget, DIY comfort level, and the specific type of vertical garden system you're using. The goal is to create an impermeable layer between the garden and the wall. Common options include heavy-duty plastic sheeting, such as 6 mil polyethylene, which is affordable and easy to find. Another excellent, more durable option is a pond liner, often made from EPDM rubber, which is designed for constant water contact and is highly puncture-resistant. For a more rigid solution, you can use corrugated plastic panels, which are lightweight and provide an additional air gap. Some pre-made vertical garden kits even come with a built-in waterproof backing, simplifying the process.
A Simple Installation Guide
Once you have your material, installation is straightforward. First, prepare the wall by cleaning it thoroughly to ensure a good seal. Measure the area your vertical garden will cover and cut your waterproof backing to be slightly larger—an extra 5-6 inches on all sides is a good rule of thumb. Affix the backing to the wall. For flexible sheets, a strong construction adhesive or a staple gun can work, but be sure to seal over any punctures. Use a high-quality waterproof construction tape or silicone sealant around the entire perimeter of the backing. This is a crucial step to prevent any water from creeping in around the edges. Ensure the barrier is smooth and flat against the wall before you hang your planters.
Beyond the Barrier: Extra Protection
While a waterproof backing is non-negotiable, a few other strategies can help manage moisture. Creating a small air gap between the backing and the planter system can improve circulation and allow any condensation to evaporate. You can do this by using small wood spacers or specialised mounting hardware. Also, consider your watering technique. Drip irrigation systems, while an investment, deliver water directly to the roots with minimal runoff. If watering by hand, do so slowly and allow the water to be absorbed before adding more to prevent overflow. Finally, choosing plants appropriate for your indoor conditions will lead to a healthier garden that requires less intensive watering.
