Growing lettuce in an urban planter box is a fantastic way to enjoy fresh greens. The most critical factor for healthy growth is providing enough space. For most lettuce varieties, a planter box should be at least 12 inches (30 cm) wide. This width allows you to comfortably plant lettuce in rows or a staggered pattern, giving each plant the 6-8 inches of space it typically needs to form a full head or lush leaves without excessive competition for water and nutrients.
Depth is equally important; aim for a container 6-8 inches (15-20 cm) deep for leafy varieties and 10-12 inches for larger heading types. A wider box, around 18-24 inches, offers more flexibility for companion planting or successive sowing. Ensure your planter has adequate drainage holes and is placed in a location that receives at least 5-6 hours of sunlight. With the right width and care, you'll be harvesting crisp, homegrown lettuce in no time.