If your urban planter box receives only four hours of direct sun, the ideal location is usually an east- or southeast-facing spot that catches gentle morning sun and falls into shade during the hottest part of the afternoon. Four hours of sun counts as partial sun rather than full sun, so the quality and timing of those hours matter more than the total alone. Morning sunlight is often better for planter boxes because it dries leaves and soil surface gently, reduces disease pressure, and avoids the intense late-afternoon heat that can stress plants in balconies, courtyards, and rooftop gardens.
Choose a spot that is open to the sky but protected from strong wind and reflected heat. A light-colored wall can bounce useful light into the box, but a dark wall, metal railing, or paved surface that radiates heat can make four hours of sun feel much harsher. Keep the planter slightly away from hot south- or west-facing walls in warm climates. In cooler climates, a south- or west-facing spot may be better if it captures warmer afternoon sun, but monitor soil moisture and leaf scorch.
Place the box close to a water source and within easy view, since partial-sun planters still dry out, especially in raised beds and windy urban sites. Avoid deep building shade, overhangs that block rain, downspouts, air-conditioning units, and narrow corners with poor air circulation. For balconies, confirm weight limits and use saucers or drip trays to protect neighbors below. A spot near a door or window makes watering and harvesting more reliable.
With four hours of sun, focus on leafy greens, herbs, and other shade-tolerant edibles rather than heat-loving fruiting crops. The ideal location gives your planter box the brightest, coolest, most accessible four hours available—usually morning sun with afternoon shade, shelter from harsh wind, reflected light without trapped heat, and convenient water access.