As winter approaches, protecting your urban planter boxes is crucial for ensuring they last for many growing seasons to come. The primary enemies are moisture, freezing temperatures, and the destructive freeze-thaw cycle. Here’s a natural guide to winterizing them.
First, remove all spent plants and soil. Old roots and debris can harbor disease. Give the empty boxes a good scrub with a mild vinegar solution to disinfect them. For wooden planters, this is the perfect time to inspect for rot or loose boards and make repairs.
The most critical step is ensuring excellent drainage to prevent water from pooling inside, freezing, and expanding, which can crack materials. Tip boxes to drain fully. For permanent boxes, consider raising them slightly with bricks or "pot feet" to keep the base dry.
Protect the material itself. For wooden planters, applying a fresh coat of sealant or linseed oil in the fall helps repel moisture. You can also add or check a durable plastic liner for extra protection, ensuring it has drainage holes.
If possible, move lightweight containers to a sheltered location like a garage or shed. For heavy or fixed boxes, group them together in a sheltered spot and consider wrapping the sides with burlap or horticultural fleece to buffer them from wind and extreme temperature shifts.
Finally, if leaving soil in, cover the surface with mulch or burlap to prevent erosion and soil compaction from rain and snow. Come spring, your well-prepared planters will be ready for a fresh start, having survived the winter in great shape.