For a small urban planter box, the best herbs are compact, productive, and easy to manage in limited space. Basil is a top choice for warm, sunny spots; choose dwarf varieties and pinch off flowers to keep leaves coming. Mint grows quickly and tolerates some shade, but it spreads aggressively, so plant it in its own container or keep it in a separate pot inside the planter box. Thyme is low-growing, drought-tolerant once established, and works well along the edge of a box. Chives are neat, narrow plants that handle small spaces well and regrow after cutting. Parsley is another reliable option, though it needs a slightly deeper section of the planter box for its roots.
For best results, use a planter box with drainage holes and fill it with light, well-draining potting mix. Most culinary herbs need about six hours of sun, though mint and parsley can manage with partial shade. Space plants according to their mature size, water when the top inch of soil feels dry, and harvest often to encourage bushy growth. Avoid overcrowding, and group herbs with similar water and light needs together.