When setting up urban planter boxes, this common gardening question deserves careful consideration. While small, lightweight containers might temporarily sit directly on paved surfaces, most planter boxes benefit significantly from proper bases. Direct ground contact creates several issues - soil becomes compacted, drainage gets restricted, and wooden boxes rapidly deteriorate from moisture exposure.
For optimal plant health, consider these approaches. Elevating boxes 2-4 inches using simple feet or a frame creates crucial air circulation underneath. This prevents waterlogging and discourages pests. Alternatively, placing planter boxes on a layer of gravel or crushed stone creates a natural drainage base that protects both your plants and the surface beneath.
The material matters greatly. Wooden planters absolutely require elevation to prevent rot, while metal and plastic containers can tolerate more ground contact if proper drainage holes exist. Remember that soil becomes incredibly heavy when wet - a 4x4 foot planter can weigh over 800 pounds. Distributed weight through a proper base prevents surface damage and stability issues.
Urban gardeners should also consider mobility. Even large planter boxes occasionally need moving for cleaning, rearranging, or seasonal changes. Integrated wheels or a separate dolly base provide this flexibility while maintaining the drainage advantages of elevation.
Ultimately, investing in a proper base system extends your planter's lifespan, improves plant vitality through better drainage, and protects your patio or balcony surface. The minor additional effort during setup pays long-term dividends for your urban garden's success.