This is a common and excellent question for any urban gardener. The short answer is: it depends. Many commercially available urban planter boxes, especially those designed for functionality, do come with pre-drilled drainage holes. However, a significant number of decorative pots and boxes, particularly those made from materials like ceramic, metal, or certain woods, may not have them. The presence of drainage is non-negotiable for plant health; without it, water accumulates at the bottom, leading to root rot, fungal diseases, and ultimately, dead plants.
If your planter box lacks drainage, you absolutely need to add it. For materials like plastic, fiberglass, or wood, you can carefully drill several holes in the bottom using an appropriate drill bit. For ceramic or clay, a special masonry bit is required. If drilling isn't an option, a popular alternative is to use the planter as a "cachepot." Simply place a smaller, plastic nursery pot with its own drainage holes inside the decorative planter. This allows you to lift the inner pot for complete drainage. Always use a high-quality potting mix, not garden soil, to ensure proper drainage and aeration. Remember, successful container gardening in the city starts from the bottom up—ensuring your plants have a way to escape excess water is the first and most critical step.