Yes—strawberries are one of the best edible crops for an urban planter box, provided the box gets enough sun and drains well. For a productive setup, choose a planter at least 8–10 inches deep (12 inches is even better), with drainage holes and a light, rich potting mix. Strawberries are shallow-rooted, so they do not need a huge container, but they do need consistent moisture and good airflow. Place the box where it receives 6–8 hours of direct sun. Day-neutral or everbearing varieties are usually the best choice for small urban spaces because they produce fruit over a longer season; June-bearing types can work too if you want one main harvest.
How many plants fit depends on the planter’s length, width, and the variety. A simple rule is to space plants about 6–8 inches apart in containers, with a little more room—8–12 inches—if your climate is humid or your box is crowded. For a single row in a narrow planter, divide the inside length by 6–8 inches. For example, a 36-inch-long box can hold roughly 4–6 plants in one row. If the box is at least 16–18 inches wide, you may fit two staggered rows, but do not overcrowd them; airflow is important for preventing mold and disease. A typical 36 x 12-inch balcony box is safer with 4–6 plants, while a 48 x 12-inch box can hold about 6–8 plants. A very small 24-inch box is best with 2–3 plants.
Plant with the crown—the point where leaves emerge—at soil level, not buried. Water regularly, especially as fruit develops, and feed with a balanced or strawberry-friendly fertilizer according to the label. Mulch can help keep moisture even, and removing runners will direct energy into fruit instead of new plants. In urban settings, pollinators may be limited, so gently shaking the flowers at midday can improve pollination. With good sun, drainage, and sensible spacing, an urban planter box can give you a surprisingly generous strawberry harvest—even on a balcony or patio.