Short answer: not automatically. A wooden urban planter box can be better in some situations, but a plastic one can be better in others. The right choice depends on where you garden, how much maintenance you want, your budget, and whether the material is safe for growing food.
Wooden planter boxes are often the better choice for serious food growing if they are made from untreated, rot-resistant wood such as cedar, cypress, redwood, or heat-treated pine. Wood looks natural in an urban setting, has good insulating properties, and is less likely to overheat in strong sun than thin plastic. It also lets the soil breathe slightly, which can help with moisture management. However, wood is heavier, costs more upfront, and can rot over time. It may also need a food-safe liner to separate the soil from the wood, especially if the wood is not explicitly food-safe. Avoid old pressure-treated timber, creosote, or unknown reclaimed wood for edibles.
Plastic planter boxes are practical, lightweight, affordable, and easy to clean. They can be a smart option for balconies, rooftops, and small urban spaces where weight matters. Good-quality food-grade HDPE or polypropylene plastic is generally considered safer for food growing than unknown recycled plastic. Plastic holds moisture well, but it can heat up in full sun and degrade under UV exposure over time. It also lacks the breathability and natural look of wood, and cheaper plastic may crack or become brittle.
For growing food, material safety matters more than the wood-versus-plastic debate. Choose food-safe materials, add drainage holes, use a quality soil mix, and make sure the box is deep enough for what you want to grow. Herbs and lettuce can do well in shallower boxes, while tomatoes, peppers, and root crops need more depth.
If you want a durable, attractive, long-term urban food garden and you are willing to maintain it, a wooden box with a food-safe liner and good drainage is often the better choice. If you need something light, budget-friendly, easy to move, and low-maintenance, a food-grade plastic box may be more practical. In short, wood is not always better than plastic for growing food, but a well-built wooden planter can be an excellent choice when it is safe, properly lined, and well drained.